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  Subjects -> BIOLOGY (Total: 2979 journals)
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    - ZOOLOGY (133 journals)

ZOOLOGY (133 journals)                     

Showing 1 - 133 of 133 Journals sorted alphabetically
Acta Herpetologica     Open Access   (Followers: 6)
Acta Theriologica     Full-text available via subscription   (Followers: 6)
Acta Zoologica     Hybrid Journal   (Followers: 6)
Acta Zoologica Cracoviensia     Free   (Followers: 2)
Acta zoológica mexicana     Open Access  
Advances in Zoology and Botany     Open Access  
African Invertebrates     Open Access  
African Journal of Herpetology     Full-text available via subscription   (Followers: 4)
African Journal of Wildlife Research     Full-text available via subscription   (Followers: 2)
African Zoology     Hybrid Journal   (Followers: 6)
American Journal of Zoological Research     Open Access   (Followers: 1)
Animal Behaviour     Hybrid Journal   (Followers: 142)
Animal Biology     Hybrid Journal   (Followers: 8)
Animal Biology & Animal Husbandry     Open Access   (Followers: 4)
Animal Biotelemetry     Open Access   (Followers: 1)
Animal Genetics     Hybrid Journal   (Followers: 8)
Animal Migration     Open Access   (Followers: 1)
Animal Studies Journal     Open Access   (Followers: 6)
Annales Zoologici     Full-text available via subscription  
Annales Zoologici Fennici     Open Access  
Annals of Animal Science     Open Access   (Followers: 1)
Annals of the Ditsong National Museum of Natural History     Full-text available via subscription   (Followers: 3)
Annual Review of Animal Biosciences     Full-text available via subscription   (Followers: 4)
Anthrozoos : A Multidisciplinary Journal of The Interactions of People & Animals     Hybrid Journal   (Followers: 6)
Applied Animal Behaviour Science     Hybrid Journal   (Followers: 17)
Applied Entomology and Zoology     Partially Free   (Followers: 2)
Aquatic Mammals     Full-text available via subscription   (Followers: 8)
Aquatic Sciences     Hybrid Journal   (Followers: 12)
Arquivos de Ciências Veterinárias e Zoologia da UNIPAR     Open Access  
Arthropod Management Tests     Hybrid Journal   (Followers: 2)
Asian Journal of Animal and Veterinary Advances     Open Access   (Followers: 8)
Australian Journal of Zoology     Hybrid Journal  
Bangladesh Journal of Zoology     Open Access  
Bioacoustics : The International Journal of Animal Sound and its Recording     Partially Free   (Followers: 2)
Biodiversidade     Open Access  
Bird Study     Full-text available via subscription   (Followers: 25)
Brazilian Journal of Veterinary Research and Animal Science     Open Access   (Followers: 8)
British Birds     Full-text available via subscription   (Followers: 24)
Bulletin of the Museum of Comparative Zoology     Full-text available via subscription   (Followers: 2)
Canadian Journal of Animal Science     Full-text available via subscription   (Followers: 4)
Canadian Journal of Zoology     Full-text available via subscription   (Followers: 17)
Canadian Zooarchaeology / Zooarchéologie canadienne     Open Access  
Contributions to Zoology     Open Access   (Followers: 3)
Current Zoology     Full-text available via subscription  
Der Zoologische Garten     Full-text available via subscription   (Followers: 2)
Ecology of Freshwater Fish     Hybrid Journal   (Followers: 18)
European Journal of Taxonomy     Open Access   (Followers: 3)
Euscorpius     Open Access  
EvoDevo     Open Access   (Followers: 3)
Fish and Fisheries     Hybrid Journal   (Followers: 29)
Frontiers in Zoology     Open Access   (Followers: 7)
Graellsia     Open Access  
Herpetology Notes     Open Access   (Followers: 5)
Hystrix, the Italian Journal of Mammalogy     Open Access  
i-Perception     Open Access   (Followers: 3)
Iheringia. Série Zoologia     Open Access   (Followers: 1)
In Vitro Cellular & Developmental Biology - Animal     Hybrid Journal   (Followers: 1)
Integrative Zoology     Hybrid Journal  
International Journal of Odonatology     Hybrid Journal   (Followers: 1)
International Journal of Zoological Research     Open Access   (Followers: 1)
International Journal of Zoology     Open Access   (Followers: 2)
International Studies on Sparrows     Open Access  
International Zoo Yearbook     Hybrid Journal   (Followers: 3)
Invertebrate Reproduction & Development     Hybrid Journal   (Followers: 3)
Italian Journal of Animal Science     Open Access   (Followers: 2)
Italian Journal of Zoology     Hybrid Journal   (Followers: 1)
Journal of Agrobiology     Open Access   (Followers: 3)
Journal of Animal Ecology     Hybrid Journal   (Followers: 61)
Journal of Animal Physiology and Animal Nutrition     Hybrid Journal   (Followers: 5)
Journal of Apicultural Science     Open Access   (Followers: 2)
Journal of Applied Animal Research     Hybrid Journal   (Followers: 3)
Journal of Basic & Applied Zoology : Physiology     Open Access   (Followers: 2)
Journal of Experimental Zoology Part A: Ecological Genetics and Physiology     Hybrid Journal   (Followers: 4)
Journal of Experimental Zoology Part B : Molecular and Developmental Evolution     Hybrid Journal   (Followers: 2)
Journal of Freshwater Ecology     Hybrid Journal   (Followers: 14)
Journal of Herpetology     Full-text available via subscription   (Followers: 12)
Journal of Morphology     Hybrid Journal   (Followers: 5)
Journal of Threatened Taxa     Open Access  
Journal of Venomous Animals and Toxins     Open Access   (Followers: 3)
Journal of Venomous Animals and Toxins including Tropical Diseases     Open Access  
Journal of Wildlife Management     Hybrid Journal   (Followers: 34)
Journal of Zoological Systematics and Evolutionary Research     Hybrid Journal   (Followers: 4)
Journal of Zoology     Hybrid Journal   (Followers: 21)
Laboratory Animals     Hybrid Journal   (Followers: 13)
Mammalia     Hybrid Journal   (Followers: 6)
Mastozoología Neotropical     Open Access  
Memorias de la Conferencia Interna en Medicina y Aprovechamiento de Fauna Silvestre, Exótica y no Convencional     Open Access  
Monographs of the Transvaal Museum     Full-text available via subscription  
Natural History Sciences     Hybrid Journal   (Followers: 1)
New Zealand Journal of Zoology     Hybrid Journal   (Followers: 4)
Papéis Avulsos de Zoologia     Open Access  
Parasite     Open Access   (Followers: 4)
Polish Journal of Entomology     Open Access   (Followers: 4)
Primate Biology     Open Access   (Followers: 1)
Protist Genomics     Open Access   (Followers: 1)
Redia : Journal of Zoology     Open Access   (Followers: 1)
Remote Sensing in Ecology and Conservation     Open Access   (Followers: 16)
Research in Zoology     Open Access   (Followers: 2)
Revista Brasileira de Reprodução Animal     Open Access  
Revista Brasileira de Zoologia     Open Access  
Revista de Biología Marina y Oceanografía     Open Access  
Revista de Educação Continuada em Medicina Veterinária e Zootecnia     Open Access  
Revista de Zoologia     Open Access   (Followers: 1)
Russian Journal of Herpetology     Full-text available via subscription   (Followers: 3)
Scientific Journal of Animal Science     Open Access   (Followers: 4)
Scientific Journal of Zoology     Open Access   (Followers: 3)
SHILAP Revista de Lepidopterologia     Open Access   (Followers: 2)
Skeletal Muscle     Open Access   (Followers: 2)
South American Journal of Herpetology     Full-text available via subscription   (Followers: 5)
Sri Lanka Journal of Aquatic Sciences     Open Access   (Followers: 1)
Travaux du Muséum National d’Histoire Naturelle “Grigore Antipa”     Open Access  
Tropical Zoology     Partially Free   (Followers: 3)
University Journal of Zoology, Rajshahi University     Open Access  
Veterinária e Zootecnia     Open Access  
Waterbirds     Full-text available via subscription   (Followers: 9)
Wildlife Society Bulletin     Hybrid Journal   (Followers: 9)
World Rabbit Science     Open Access  
Zoo Biology     Hybrid Journal   (Followers: 9)
ZooKeys     Open Access   (Followers: 5)
Zoologia (Curitiba)     Open Access   (Followers: 1)
Zoologica Poloniae : The Journal of Polish Zoological Society     Open Access   (Followers: 1)
Zoologica Scripta     Hybrid Journal   (Followers: 3)
Zoological Journal of the Linnean Society     Hybrid Journal   (Followers: 11)
Zoological Letters     Open Access  
Zoological Science     Full-text available via subscription   (Followers: 2)
Zoological Studies     Open Access   (Followers: 1)
Zoologische Mededelingen     Open Access  
Zoologischer Anzeiger - A Journal of Comparative Zoology     Hybrid Journal  
Zoologist (The)     Full-text available via subscription  
Zoology     Hybrid Journal   (Followers: 6)
Zoology and Ecology     Hybrid Journal   (Followers: 5)
Zoomorphology     Hybrid Journal   (Followers: 3)
Zoosystematics and Evolution - Mitteilungen Aus Dem Museum Fur Naturkunde Zu Berlin     Open Access   (Followers: 1)

           

Journal Cover Journal of Animal Ecology
  [SJR: 3.359]   [H-I: 119]   [61 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0021-8790 - ISSN (Online) 1365-2656
   Published by John Wiley and Sons Homepage  [1589 journals]
  • Personality, immune response and reproductive success: An appraisal of the
           pace-of-life syndrome hypothesis
    • Authors: Karine Monceau; François-Xavier Dechaume-Moncharmont, Jérôme Moreau, Camille Lucas, Rémi Capoduro, Sébastien Motreuil, Yannick Moret
      Abstract: The pace-of-life syndrome (POLS) hypothesis is an extended concept of the life history theory that includes behavioural traits. The studies challenging the POLS hypothesis often focus on the relationships between a single personality trait and a physiological and/or life history traits. While pathogens represent a major selective pressure, few studies have been interested in testing relationships between behavioural syndrome, and several fitness components including immunity.The aim of this study is to address this question in the mealworm beetle, Tenebrio molitor, a model species in immunity studies. The personality score was estimated from a multidimensional syndrome based of four repeatable behavioural traits.In a first experiment, we investigated its relationship with two measures of fitness (reproduction and survival) and three components of the innate immunity (haemocyte concentration, and levels of activity of the phenoloxidase including the total proenzyme and the naturally activated one) to challenge the POLS hypothesis in T. molitor. Overall, we found a relationship between behavioural syndrome and reproductive success in this species, thus supporting the POLS hypothesis. We also showed a sex-specific relationship between behavioural syndrome and basal immune parameters.In a second experiment, we tested whether this observed relationship with innate immunity could be confirmed in term of differential survival after challenging by entomopathogenic bacteria, Bacillus thuringiensis. In this case, no significant relationship was evidenced.We recommend that future researchers on the POLS should control for differences in evolutionary trajectory between sexes and to pay attention to the choice of the proxy used, especially when looking at immune traits.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-20T07:11:07.291506-05:
      DOI: 10.1111/1365-2656.12684
       
  • Long-term species loss and homogenization of moth communities in Central
           Europe
    • Authors: Anu Valtonen; Anikó Hirka, Levente Szőcs, Matthew P. Ayres, Heikki Roininen, György Csóka
      Abstract: As global biodiversity continues to decline steeply, it is becoming increasingly important to understand diversity patterns at local and regional scales.Changes in land use and climate, nitrogen deposition and invasive species are the most important threats to global biodiversity. Because land use changes tend to benefit a few species but impede many, the expected outcome is generally decreasing population sizes, decreasing species richness at local and regional scales, and increasing similarity of species compositions across sites (biotic homogenization). Homogenization can be also driven by invasive species or effects of soil eutrophication propagating to higher trophic levels. In contrast, in the absence of increasing aridity, climate warming is predicted to generally increase abundances and species richness of poikilotherms at local and regional scales.We tested these predictions with data from one of the few existing monitoring programs on biodiversity in the world dating to the 1960s, where the abundance of 878 species of macro-moths have been measured daily at seven sites across Hungary.Our analyses revealed a dramatic rate of regional species loss and homogenization of community compositions across sites. Species with restricted distribution range, specialized diet, or dry grassland habitat were more likely than others to disappear from the community.In global context, the contrasting effects of climate change and land use changes could explain why the predicted enriching effects from climate warming are not always realized.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-19T12:53:04.978033-05:
      DOI: 10.1111/1365-2656.12687
       
  • Drivers of species role in avian seed-dispersal mutualistic networks
    • Authors: Esther Sebastián-González
      Abstract: The mutualistic interaction between frugivore birds and the fruiting plants they disperse presents an asymmetric interaction pattern, with some species having a more important role (i.e. being essential) for maintaining the structure and functioning of the interaction network. The identification of the biological characteristics of these species is of major importance for the understanding and conservation of seed-dispersal interactions.In this study, I use a network approach and avian seed-dispersal networks from 23 different geographical areas to test 5 hypotheses about species characteristics determining the structure of the assemblage.I expected (1) large birds to forage on a large number of fruits and (2) large fruits to be dispersed by few bird species (because of morphological constraints), (3) highly energetic fruits to be dispersed by more bird species (in accordance with optimal foraging theory). Besides the number of interacting partners, I also expected (4) large birds and (5) small energetic fruits to be important for the maintenance of the structure of the interactions in seed-dispersal networks. Since species that are closely related are more likely to be similar to each other, I performed phylogenetically corrected analyses to account for this data dependence.Although bird size was not associated to species important in the maintenance of the structure of the seed-dispersal community, I identified that bird species whose diet was strongly dependent on fruits were important for the structure of the network. Regarding the plants, I found that large fruits were dispersed by fewer species, but the most important attribute to predict the role of a fruit was its energy content (higher energy, more bird species dispersing the plant, but low-energy fruits being of conservation concern because they are dispersed by specific species).The results of this study suggest that the role of the species in seed-dispersal assemblages seems to be determined by the role of the species as consumers (frugivory degree for animals) or by their nutritional inputs (energy content for fruits) rather than by morphological constrains.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-17T15:45:24.829406-05:
      DOI: 10.1111/1365-2656.12686
       
  • An Arctic predator-prey system in flux: climate change impacts on coastal
           space use by polar bears and ringed seals
    • Authors: Charmain D. Hamilton; Kit M. Kovacs, Rolf A. Ims, Jon Aars, Christian Lydersen
      Abstract: 1.Climate change is impacting different species at different rates, leading to alterations in biological interactions with ramifications for wider ecosystem functioning. Understanding these alterations can help improve predictive capacity and inform management efforts designed to mitigate against negative impacts.2.We investigated how the movement and space use patterns of polar bears (Ursus maritimus) in coastal areas in Svalbard, Norway, have been altered by a sudden decline in sea ice that occurred in 2006. We also investigated whether the spatial overlap between polar bears and their traditionally most important prey, ringed seals (Pusa hispida), has been affected by the sea-ice decline, as polar bears are dependent on a sea-ice platform for hunting seals.3.We attached biotelemetry devices to ringed seals (n=60, both sexes) and polar bears (n=67, all females) before (2002-2004) and after (2010-2013) a sudden decline in sea ice in Svalbard. We used linear mixed-effects models to evaluate the association of these species to environmental features and an approach based on Time Spent in Area to investigate changes in spatial overlap between the two species.4.Following the sea-ice reduction, polar bears spent the same amount of time close to tidal glacier fronts in the spring but less time in these areas during the summer and autumn. However, ringed seals did not alter their association with glacier fronts during summer, leading to a major decrease in spatial overlap values between these species in Svalbard's coastal areas. Polar bears now move greater distances daily and spend more time close to ground-nesting bird colonies, where bear predation can have substantial local effects.5.Our results indicate that sea-ice declines have impacted the degree of spatial overlap and hence the strength of the predator-prey relationship between polar bears and ringed seals, with consequences for the wider Arctic marine and terrestrial ecosystems. Shifts in ecological interactions are likely to become more widespread in many ecosystems as both predators and prey respond to changing environmental conditions induced by global warming, highlighting the importance of multi-species studies.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-17T15:40:25.689593-05:
      DOI: 10.1111/1365-2656.12685
       
  • Fine-scale population dynamics in a marine fish species inferred from
           dynamic state-space models
    • Authors: Lauren A. Rogers; Geir O. Storvik, Halvor Knutsen, Esben M. Olsen, Nils Chr. Stenseth
      Abstract: 1.Identifying the spatial scale of population structuring is critical for the conservation of natural populations and for drawing accurate ecological inferences. However, population studies often use spatially aggregated data to draw inferences about population trends and drivers, potentially masking ecologically relevant population sub-structure and dynamics.2.The goals of this study were to investigate how population dynamics models with and without spatial structure affect inferences on population trends and the identification of intrinsic drivers of population dynamics (e.g. density dependence).3.Specifically, we developed dynamic, age-structured, state-space models to test different hypotheses regarding the spatial structure of a population complex of coastal Atlantic cod (Gadus morhua). Data were from a 93-year survey of juvenile (age 0 and 1) cod sampled along >200 km of the Norwegian Skagerrak coast. We compared two models: one which assumes all sampled cod belong to one larger population, and a second which assumes that each fjord contains a unique population with locally-determined dynamics. Using the best supported model, we then reconstructed the historical spatial and temporal dynamics of Skagerrak coastal cod.4.Cross-validation showed that the spatially-structured model with local dynamics had better predictive ability. Further, posterior predictive checks showed that a model which assumes one homogeneous population failed to capture the spatial correlation pattern present in the survey data. The spatially-structured model indicated that population trends differed markedly among fjords, as did estimates of population parameters including density-dependent survival. Recent biomass was estimated to be at a near-record low all along the coast, but the finer-scale model indicated that the decline occurred at different times in different regions. Warm temperatures were associated with poor recruitment, but local changes in habitat and fishing pressure may have played a role in driving local dynamics.5.More generally, we demonstrated how state-space models can be used to test evidence for population spatial structure based on survey time-series data. Our study shows the importance of considering spatially-structured dynamics, as the inferences from such an approach can lead to a different ecological understanding of the drivers of population declines, and fundamentally different management actions to restore populations.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-09T23:52:28.841968-05:
      DOI: 10.1111/1365-2656.12678
       
  • Individual heterogeneity determines sex differences in mortality in a
           monogamous bird with reversed sexual dimorphism
    • Authors: Fernando Colchero; Alix Eva Aliaga, Owen Jones, Dalia Amor Conde
      Abstract: 1.Sex differences in mortality are pervasive in vertebrates, and usually result in shorter life spans in the larger sex, although the underlying mechanisms are still unclear. On the other hand, differences in frailty among individuals (i.e. individual heterogeneity), can play a major role in shaping demographic trajectories in wild populations. The link between these two processes has seldom been explored.2.We used Bayesian survival trajectory analysis to study age-specific mortality trajectories in the Eurasian sparrowhawk (Accipiter nisus), a monogamous raptor with reversed sexual size dimorphism. We tested the effect of individual heterogeneity on age-specific mortality, and the extent by which this heterogeneity was determined by average reproductive output and wing length as measures of an individual's frailty.3.We found that sex differences in age-specific mortality were primarily driven by the differences in individual heterogeneity between the two sexes. Females were more heterogeneous than males in their level of frailty. Thus, a larger number of females with low frailty are able to survive to older ages than males, with life expectancy for the least frail adult females reaching up to 4.23 years, while for the least frail adult males it was of 2.68 years.4.We found that 50% of this heterogeneity was determined by average reproductive output and wing length in both sexes. For both, individuals with high average reproductive output had also higher chances to survive. However, the effect of wing length was different between the two sexes. While larger females had higher survival, larger males had lower chances to survive.5.Our results contribute a novel perspective to the ongoing debate about the mechanisms that drive sex differences in vital rates in vertebrates. Although we found that variables that relate to the cost of reproduction and sexual dimorphism are at least partially involved in determing these sex differences, it is through their effect on the level of frailty that they affect age patterns of mortality. Therefore, our results raise the possibility that observed differences in age-specific demographic rates may in fact be driven by differences in individual heterogeneity.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-09T23:41:57.294072-05:
      DOI: 10.1111/1365-2656.12677
       
  • Functional responses in animal movement explain spatial heterogeneity in
           animal-habitat relationships
    • Authors: Tom H.E. Mason; Daniel Fortin
      Abstract: 1.Understanding why heterogeneity exists in animal-habitat spatial relationships is critical for identifying the drivers of animal distributions. Functional responses in habitat selection – whereby animals adjust their habitat selection depending on habitat availability – are useful for describing animal-habitat spatial heterogeneity. However, they could be yielded by different movement tactics, involving contrasting inter-specific interactions.2.Identifying functional responses in animal movement, rather than in emergent spatial patterns like habitat selection, could disentangle the effects of different movement behaviours on spatial heterogeneity in animal-habitat relationships. This would clarify how functional responses in habitat selection emerge and provide a general tool for understanding the mechanistic drivers of animal distributions.3.We tested this approach using data from GPS-collared woodland caribou (Rangifer tarandus), a prey species under top-down control. We tested how caribou selected and moved with respect to a key resource (lichen-conifer stands) as a function of the availability of surrounding refuge land-cover (closed-conifer stands), using step selection functions.4.Caribou selected resource patches more strongly in areas richer in refuge land-cover – a functional response in habitat selection. However, adjustments in multiple movement behaviours could have generated this pattern: stronger directed movement towards resources patches and/or longer residency within resource patches, in areas richer in refuges. Different contributions of these behaviours would produce contrasting forager spatial dynamics.5.We identified functional responses in both movement behaviours: caribou were more likely to move towards resource patches in areas richer in refuge land-cover, and to remain in these patches during movement steps. This tactic enables caribou to forage for longer in safer areas where they can rapidly seek refuge in dense cover when predators are detected.6.Our study shows that functional responses in movement can expose the context-dependent movement decisions that generate heterogeneity in animal-habitat spatial relationships. We used these functional responses to characterise anti-predator movement tactics employed by a large herbivore, but they could be applied in many different scenarios. The movement rules from functional responses in movement are well-suited to integration in spatial explicit individual-based models for forecasting animal distributions in landscapes undergoing environmental change.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-08T02:00:59.608814-05:
      DOI: 10.1111/1365-2656.12682
       
  • The many faces of fear: A synthesis of the methodological variation in
           characterizing predation risk
    • Authors: Remington J. Moll; Kyle M. Redilla, Tutilo Mudumba, Arthur B. Muneza, Steven M. Gray, Leandro Abade, Matt W. Hayward, Joshua J. Millspaugh, Robert A. Montgomery
      Abstract: 1.Predators affect prey by killing them directly (lethal effects) and by inducing costly antipredator behaviors in living prey (risk effects). Risk effects can strongly influence prey populations and cascade through trophic systems. A prerequisite for assessing risk effects is characterizing the spatiotemporal variation in predation risk.2.Risk effects research has experienced rapid growth in the last several decades. However, preliminary assessments of the resultant literature suggest that researchers characterize predation risk using a variety of techniques. The implications of this methodological variation for inference and comparability among studies have not been well-recognized or formally synthesized.3.We couple a literature survey with a hierarchical framework, developed from established theory, to quantify the methodological variation in characterizing risk using carnivore-ungulate systems as a case study. Via this process, we documented 244 metrics of risk from 141 studies falling into at least 13 distinct subcategories within 3 broader categories.4.Both empirical and theoretical work suggest risk and its effects on prey constitute a complex, multi-dimensional process with expressions varying by spatiotemporal scale. Our survey suggests this multi-scale complexity is reflected in the literature as a whole but often underappreciated in any given study, which complicates comparability among studies and leads to an overemphasis on documenting the presence of risk effects rather than their mechanisms or scale of influence.5.We suggest risk metrics be placed in a more concrete conceptual framework to clarify inference surrounding risk effects and their cascading effects throughout ecosystems. We recommend studies 1) take a multi-scale approach to characterizing risk, 2) explicitly consider “true” predation risk (probability of predation per unit time), and 3) use risk metrics that facilitate comparison among studies and the evaluation of multiple competing hypotheses. Addressing the pressing questions in risk effects research, including how, to what extent, and on what scale they occur, requires leveraging the advantages of the many methods available to characterize risk while minimizing the confusion caused by variability in their application.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-08T01:56:00.281455-05:
      DOI: 10.1111/1365-2656.12680
       
  • Benefits of the destinations, not costs of the journeys, shape partial
           migration patterns
    • Authors: Charles B. Yackulic; Stephen Blake, Guillaume Bastille-Rousseau
      Abstract: 1.The reasons that lead some animals to seasonally migrate, and others to remain in the same area year-round, are poorly understood. Associations between traits, such as body size, and migration provide clues. For example, larger species and individuals are more likely to migrate.2.One explanation for this size bias in migration is that larger animals are capable of moving faster (movement hypothesis). However, body size is linked to many other biological processes. For instance, the energetic balances of larger animals are generally more sensitive to variation in food density because of body size effects on foraging and metabolism and this sensitivity could drive migratory decisions (forage hypothesis).3.Identifying the primary selective forces that drive migration ultimately requires quantifying fitness impacts over the full annual migratory cycle. Here, we develop a full annual migratory cycle model from metabolic and foraging theory to compare the importance of the forage and movement hypotheses. We parameterize the model for Galapagos tortoises, which were recently discovered to be size-dependent altitudinal migrants.4.The model predicts phenomena not included in model development including maximum body sizes, the body size at which individuals begin to migrate, and the seasonal timing of migration and these predictions generally agree with available data. Scenarios strongly support the forage hypothesis over the movement hypothesis. Furthermore, male Galapagos tortoises on Santa Cruz Island would be unable to grow to their enormous sizes without access to both highlands and lowlands.5.Whereas recent research has focused on links between traits and the migratory phases of the migratory cycle, we find that effects of body size on the non-migratory phases are far more important determinants of the propensity to migrate. Larger animals are more sensitive to changing forage conditions than smaller animals with implications for maintenance of migration and body size in the face of environmental change.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-08T01:50:55.595225-05:
      DOI: 10.1111/1365-2656.12679
       
  • The Causes of Dispersal and the Cost of Carryover Effects for an
           Endangered Bird in a Dynamic Wetland Landscape
    • Authors: Ellen P. Robertson; Robert J. Fletcher, James D. Austin
      Abstract: 1.The decision to disperse or remain philopatric between breeding seasons has important implications for both ecology and evolution, including the potential for carryover effects, where an individual's previous history affects their current performance. Carryover effects are increasingly documented although underlying mechanisms remain unclear.2.Here we test for potential carryover effects and their mechanisms by uniting hypotheses for the causes and consequences of habitat selection and dispersal across space and time. We linked hypotheses regarding different types of factors and information (environmental conditions, personal and public information) predicted to impact reproductive success and dispersal for an endangered, wetland-dependent bird, the snail kite (Rostrhamus sociabilis plumbeus). To do so, we coupled structural equation modeling with 20 years of mark-recapture and nesting data across the breeding range of this species to isolate potential direct and indirect effects of these factors.3.We found that water depth at nest sites explained subsequent emigration rates via an indirect path through the use of personal, not public, information. Importantly, we found that these dispersers tended to initiate nests later the following breeding season. This pattern explained a phenological mismatch of nesting with hydrological conditions, whereby immigrants tended to nest later, late nesters tended to experience lower water depths, higher nest failure occurred at lower water depths, and higher nest failure explained subsequent breeding dispersal.4.These results identified a novel potential mechanism for carryover effects: a phenological mismatch with environmental conditions (water depth) that occurred potentially due to time costs of dispersal. Our results also highlighted a substantial benefit of philopatry-NDASH-earlier initiation of reproduction-NDASH-which allows philopatric individuals to better coincide with environmental conditions that are beneficial for successful reproduction.5.These results have implications for our mechanistic understanding and prediction of carryover effects, and emphasize that local conservation strategies, such as water management, can explain future demography at distant sites connected through dispersal.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-05T02:35:47.909042-05:
      DOI: 10.1111/1365-2656.12676
       
  • Multi-modal defenses in aphids offer redundant protection and increased
           costs likely impeding a protective mutualism
    • Authors: Adam J. Martinez; Matthew R. Doremus, Laura J. Kraft, Kyungsun L. Kim, Kerry M. Oliver
      Abstract: 1.The pea aphid, Acyrthosiphon pisum, maintains extreme variation in resistance to its most common parasitoid wasp enemy, Aphidius ervi, which is sourced from two known mechanisms: protective bacterial symbionts, most commonly Hamiltonella defensa, or endogenously encoded defenses. We have recently found that individual aphids may employ each defense individually, occasionally both defenses together, or neither.2.In field populations, Hamiltonella-infected aphids are found at low to moderate frequencies and while less is known about the frequency of resistant genotypes, they show up less often than susceptible genotypes in field collections. To better understand these patterns, we sought to compare the strengths and costs of both types of defense, individually and together, in order to elucidate the selective pressures that maintain multi-modal defense mechanisms or that may favor one over the other.3.We experimentally infected five aphid genotypes (two lowly and three highly resistant), each with two symbiont strains, Hamiltonella-APSE8 (moderate protection) and Hamiltonella-APSE3 (high protection). This resulted in three sublines per genotype: uninfected, +APSE8, and +APSE3. Each of the fifteen total sublines was first subjected to a parasitism assay to determine its resistance phenotype and in a second experiment a subset were chosen to compare fitness (fecundity and survivorship) in presence and absence of parasitism.4.In susceptible aphid genotypes, parasitized sublines infected with Hamiltonella generally showed increased protection with direct fitness benefits, but clear infection costs to fitness in the absence of parasitism. In resistant genotypes, Hamiltonella infection rarely conferred additional protection, often further reduced fecundity and survivorship when enemy challenged, and resulted in constitutive fitness costs in the absence of parasitism. We also identified strong aphid-genotype X symbiont-strain interactions, such that the best defensive strategy against parasitoids varied for each aphid genotype; one performed best with no protective symbionts, the others with particular strains of Hamiltonella.5.This surprising variability in outcomes helps explain why Hamiltonella infection frequencies are often intermediate and do not strongly track parasitism frequencies in field populations. We also find that variation in endogenous traits, such as resistance, among host genotypes may offer redundancy and generally limit the invasion potential of mutualistic microbes in insects.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-05T02:35:41.575759-05:
      DOI: 10.1111/1365-2656.12675
       
  • A framework for modeling range shifts and migrations: Asking whether,
           whither, when, and will it return
    • Authors: Eliezer Gurarie; Francesca Cagnacci, Wibke Peters, Chris Fleming, Justin M. Calabrese, Thomas Müller, William F. Fagan
      Abstract: Many animals undertake movements that are longer-scaled and more directed than their typical home ranging behavior. Most notably, these movements include seasonal migrations (e.g. between breeding and feeding grounds), but also natal dispersal, nomadic range shifts, and responses to local environmental disruptions. While various heuristic tools exist for identifying range shifts and migrations, none explicitly model the movement of the animals within a statistical framework that facilitates quantitative comparisons.We present the mechanistic range shift analysis (MRSA), a method to estimate a suite of range shift parameters: times of initiation, duration of transitions, centroids and areas of respective ranges. The method can take the autocorrelation and irregular sampling that is characteristic of much movement data into account. The mechanistic parameters suggest an intuitive measure, the range shift index, for the extent of a range shift. The likelihood based estimation further allows for statistical tests of several relevant hypotheses, including a range shift test, a stopover test, and a site-fidelity test. The analysis tools are provided in an R package (marcher).We applied the MRSA to a population of GPS tracked roe deer (Capreolus capreolus) in the Italian Alps between 2005 and 2008. With respect to seasonal migration, this population is extremely variable and difficult to classify. Using the MRSA, we were able to quantify the behaviors across the population and among individuals across years, identifying extents, durations and locations of seasonal range shifts, including cases that would have been ambiguous to detect using existing tools.The strongest patterns were differences across years: many animals simply did not perform a seasonal migration to wintering grounds during the mild winter of 2006-07, even though some of these same animals did move extensively in other, harsher winters. For seasonal migrants, however, site fidelity across years was extremely high, even after skipping an entire seasonal migration. These results suggest that for roe deer behavioral plasticity and tactical responses to immediate environmental cues are reflected in the decision of whether rather than where to migrate. The MRSA also revealed a trade-off between the probability of migrating and the size of a home range.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-01T02:55:36.38321-05:0
      DOI: 10.1111/1365-2656.12674
       
  • The effects of ant nests on soil fertility and plant performance: a
           meta-analysis
    • Authors: Alejandro G. Farji-Brener; Victoria Werenkraut
      Abstract: Ants are recognized as one of the major sources of soil disturbance worldwide. However, this view is largely based on isolated studies and qualitative reviews. Here, for the first time, we quantitatively determined whether ant nests affect soil fertility and plant performance, and identified the possible sources of variation of these effects.Using Bayesian mixed-models meta-analysis we tested the hypotheses that ant effects on soil fertility and plant performance depend on the substrate sampled, ant feeding type, latitude, habitat and the plant response variable measured.Ant nests showed higher nutrient and cation content than adjacent non-nest soil samples, but similar pH. Nutrient content was higher in ant refuse materials than in nest soils. The fertilizer effect of ant nests was also higher in dry habitats than in grasslands or savannas. Cation content was higher in nests of plant-feeding ants than in nests of omnivorous species, and lower in nests from agro-ecosystems than in nests from any other habitat.Plants showed higher green/root biomass and fitness on ant nests soils than in adjacent, non-nest sites; but plant density and diversity were unaffected by the presence of ant nests. Root growth was particularly higher in refuse materials than in ant nest soils, in leaf-cutting ant nests and in deserts habitats.Our results confirm the major role of ant nests in influencing soil fertility and vegetation patterns and provide information about the factors that mediate these effects. First, ant nests improve soil fertility mainly through the accumulation of refuse materials. Thus, different refuse dump locations (external or in underground nest chambers) could benefit different vegetation life forms. Second, ant nests could increase plant diversity at larger spatial scales only if the identity of favored plants changes along environmental gradients (i.e., enhancing ß–diversity). Third, ant species that feed on plants play a relevant role fertilizing soils, which may balance their known influence as primary consumers. Fourth, the effects of ant nests as fertility islands are larger in arid lands, possibly because fertility is intrinsically lower in these habitats. Overall, this study provide novel and quantitative evidence confirming that ant nests are key soil modifiers, emphasizing their role as ecological engineers.This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-31T20:35:26.518984-05:
      DOI: 10.1111/1365-2656.12672
       
  • Climatic Variation Modulates the Indirect Effects of Large Herbivores on
           Small-Mammal Habitat Use
    • Authors: Ryan A. Long; Alois Wambua, Jacob R. Goheen, Todd M. Palmer, Robert M. Pringle
      Abstract: Large mammalian herbivores (LMH) strongly shape the composition and architecture of plant communities. A growing literature shows that negative direct effects of LMH on vegetation frequently propagate to suppress the abundance of smaller consumers. Indirect effects of LMH on the behaviour of these consumers, however, have received comparatively little attention despite their potential ecological significance.We sought to understand (i) how LMH indirectly shape small-mammal habitat use by altering the density and distribution of understory plants; (ii) how these effects vary with climatic context (here, seasonality in rainfall); and (iii) the extent to which behavioural responses of small mammals are contingent upon small-mammal density.We tested the effects of a diverse LMH community on small-mammal habitat use using four years of spatially explicit small-mammal-trapping and vegetation data from the UHURU Experiment, a replicated set of LMH exclosures in semi-arid Kenyan savanna.Small-mammal habitat use was positively associated with tree density and negatively associated with bare (unvegetated) patches in all plots and seasons. In the presence of LMH, and especially during the dry season, small mammals consistently selected tree cover and avoided bare patches. In contrast, when LMH were excluded, small mammals were weakly associated with tree cover and did not avoid bare patches as strongly. These behavioural responses of small mammals were largely unaffected by changes in small-mammal density associated with LMH exclusion.Our results show that LMH indirectly affect small-mammal behaviour, and that these effects are influenced by climate and can arise via density-independent mechanisms. This raises the possibility that anthropogenic LMH declines might interact with changing patterns of rainfall to alter small-mammal distribution and behaviour, independent of numerical responses by small mammals to these perturbations. For example, increased rainfall in East Africa (as predicted in many recent climate-model simulations) may relax constraints on small-mammal distribution where LMH are rare or absent, whereas increased aridity and/or drought frequency may tighten them.This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-25T09:35:25.961347-05:
      DOI: 10.1111/1365-2656.12669
       
  • Effects of predatory ants within and across ecosystems in bromeliad food
           webs
    • Authors: Ana Z. Gonçalves; Diane S. Srivastava, Paulo S. Oliveira, Gustavo Q. Romero
      Abstract: Predation is one of the most fundamental ecological processes affecting biotic communities. Terrestrial predators that live at ecosystem boundaries may alter the diversity of terrestrial organisms, but they may also have cross-ecosystem cascading effects when they feed on organisms with complex life cycles (i.e., organisms that shift from aquatic juvenile stages to terrestrial adult stages) or inhibit female oviposition in the aquatic environment.The predatory ant Odontomachus hastatus establishes its colonies among roots of Vriesea procera, an epiphytic bromeliad species with water-filled tanks that shelters many terrestrial and aquatic organisms. Ants may impact terrestrial communities and deter adult insects from ovipositing in the water of bromeliads via consumptive and non-consumptive effects. Ants do not forage within the aquatic environment; thus, they may be more efficient predators on terrestrial organisms. Therefore, we predict that ants will have stronger effects on terrestrial than aquatic food webs. However, such effects may also be site contingent and depend on the local composition of food webs.To test our hypothesis, we surveyed bromeliads with and without O. hastatus colonies from three different coastal field sites in the Atlantic Forest of southeast Brazil, and quantified the effect of this predatory ant on the composition, density and richness of aquatic and terrestrial metazoans found in these bromeliads.We found that ants changed the composition and reduced the overall density of aquatic and terrestrial metazoans in bromeliad ecosystems. However, effects of ants on species diversity were contingent on site. In general terms, the effects of the ant on aquatic and terrestrial metazoan communities were similar in strength and magnitude. Ants reduced the density of virtually all aquatic functional groups, especially detritivore insects as well as metazoans that reach bromeliads through phoresy on the skin of terrestrial animals (i.e., Ostracoda and Helobdella sp.).Our results suggest that the cross-ecosystem effect of this terrestrial predator on the aquatic metazoans was at least as strong as its within-ecosystem effect on the terrestrial ecosystem, and demonstrates that the same predator can simultaneously initiate cascades in multiple ecosystems.This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-25T09:35:23.890321-05:
      DOI: 10.1111/1365-2656.12671
       
  • Incorporating in situ habitat patchiness in site selection models reveals
           that site fidelity is not always a consequence of animal choice
    • Authors: Aline S. Martinez; Eduardo V. Queiroz, Mitch Bryson, Maria Byrne, Ross A. Coleman
      Abstract: 1.Understanding site fidelity is important in animal ecology, but evidence is lacking that this behaviour is due to an animal choosing a specific location. To discern site selection behaviour it is necessary to consider the spatial distribution of habitats that animals can occupy within a landscape. Tracking animals and defining clear habitat boundaries, however, is often difficult.2.We use in situ habitat distribution data and animal movement simulations to investigate behavioural choice in site fidelity patterns. We resolved the difficulty of gathering data by working with intertidal rock pool systems, which are of manageable size and where boundaries are easy to define. Movements of the intertidal starfish Parvulastra exigua were quantified to test the hypotheses that (1) this species displays fidelity to a particular rock pool and that (2) rock pool fidelity is due to site selection behaviour. Observed patterns of individuals (n=10 starfish) returning to a previously occupied rock pool (n = 5 pools per location) were tested against an expected null distribution generated through simulations of random movements within their natural patchy environment.3. Starfish exhibited site selection behaviour at only one location even though site fidelity was high (av. 7.4 starfish out of 10 found in test pools) in 2 of the 3 locations. The random chance of a starfish returning to a pool increased 67% for each metre further a rock pool was from the original pool, and 120% for each square metre increase in surface area of an original pool. The decision of returning to an original rock pool was influenced by food availability. When microalgal cover was > 60%, there was a ~ 50% chance of animals staying faithful to that pool.4. Our results show the importance to consider spatial distribution of habitats in understanding patterns of animal movement associated with animal choices and site fidelity. Returning to a particular place does not necessarily mean that an animal is homing; it may be the only place to go.This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-25T09:30:27.321492-05:
      DOI: 10.1111/1365-2656.12668
       
  • Integrating lipid storage into general representations of fish energetics
    • Authors: Benjamin T. Martin; Ron Heintz, Eric M. Danner, Roger M. Nisbet
      Abstract: 1.Fish, even of the same species, can exhibit substantial variation in energy density (energy per unit wet weight). Most of this variation is due to differences in the amount of storage lipids. In addition to their importance as energy reserves for reproduction and for survival during unfavorable conditions, the accumulation of lipids represents a large energetic flux for many species, so figuring out how this energy flux is integrated with other major energy fluxes (growth, reproduction) is critical for any general theory of organismal energetics.2.Here we synthesize data from a wide range of fish species and identify patterns of intraspecific variation in energy storage, and use these patterns to formulate a general model of energy allocation between growth, lipid storage, and reproduction in fishes.3.From the compiled data we identified two patterns: (1) energy density increases with body size during the juvenile period, but is invariant with body size within the adult size range for most species, and (2) energy density changes across seasons, with depletion over winter, but increases fastest in periods of transition between favorable and unfavorable conditions for growth (i.e. fall).4.Based on these patterns we propose DEBlipid, a simple, general model of energy allocation that is closely related to a simplified version of Dynamic Energy Budget theory, DEBkiss. The crux of the model is that assimilated energy is partitioned, with κ fraction of energy allocated to pay maintenance costs first, and the surplus allocated to growth, and 1- κ fraction of assimilated energy is allocated to accumulating storage lipids during the juvenile phase, and later to reproduction as adults. This mechanism, in addition to capturing the two patterns that motivated the model, was able to predict lipid dynamics in a novel context, the migration of anadromous fish from low food freshwater to high food marine environments. Furthermore, the model was used to explain intra and interspecific variation in reproductive output based on patterns of lipid accumulation as juveniles.5.Our results suggest that many seemingly complex, adaptive energy allocation strategies in response to ontogeny, seasonality, and habitat quality can emerge from a simple physiological heuristic.This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-22T02:28:34.63885-05:0
      DOI: 10.1111/1365-2656.12667
       
  • Isotopic niche partitioning between two apex predators over time
    • Authors: M. Drago; L. Cardona, V. Franco-Trecu, E. A. Crespo, D. Vales, F. Borella, L. Zenteno, E. M. Gonzáles, P. Inchausti
      Abstract: 1.Stable isotope analyses have become an important tool in reconstructing diets, analyzing resource use patterns, elucidating trophic relations among predators and understanding the structure of food webs.2.Here, we use stable carbon and nitrogen isotope ratios in bone collagen to reconstruct and compare the isotopic niches of adult South American fur seals (Arctocephalus australis; n = 86) and sea lions (Otaria flavescens; n = 49) –two otariid species with marked morphological differences– in the Río de la Plata estuary (Argentina - Uruguay) and the adjacent Atlantic Ocean during the second half of the 20th century and the beginning of the 21st century. Samples from the middle Holocene (n = 7 fur seals and n = 5 sea lions) are also included in order to provide a reference point for characterizing resource partitioning before major anthropogenic modifications of the environment.3.We found that the South American fur seals and South American sea lions had distinct isotopic niches during the middle Holocene. Isotopic niche segregation was similar at the beginning of the second half of the 20th century, but has diminished over time.4.The progressive convergence of the isotopic niches of these two otariids during the second half of the 20th century and the beginning of the 21st century is most likely due to the increased reliance of South American fur seals on demersal prey.5.This recent dietary change of South American fur seals can be explained by at least two non-mutually exclusive mechanisms: (i) the decrease in the abundance of sympatric South American sea lions as a consequence of small colony size and high pup mortality resulting from commercial sealing; and (ii) the decrease in the average size of demersal fishes due to intense fishing of the larger class sizes, which may have increased their accessibility to those eared seals with a smaller mouth gape, i.e., South American fur seals of both sexes and female South American sea lions.This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-22T02:22:09.326967-05:
      DOI: 10.1111/1365-2656.12666
       
  • The benefits of coinfection: Trematodes alter disease outcomes associated
           with virus infection
    • Authors: Vanessa P. Wuerthner; Jessica Hua, Jason T. Hoverman
      Abstract: 1.Coinfections are increasingly recognized as important drivers of disease dynamics. Consequently, greater emphasis has been placed on integrating principles from community ecology with disease ecology to understand within-host interactions among parasites. Using larval amphibians and two amphibian parasites (ranaviruses and the trematode Echinoparyphium sp.), we examined the influence of coinfection on disease outcomes.2.Our first objective was to examine how priority effects (the timing and sequence of parasite exposure) influence infection and disease outcomes in the laboratory. We found that interactions between the parasites were asymmetric; prior infection with Echinoparyphium reduced ranaviral loads by 9% but there was no reciprocal effect of prior ranavirus infection on Echinoparyphium load. Additionally, survival rates of hosts (larval gray treefrogs; Hyla versicolor) infected with Echinoparyphium 10 days prior to virus exposure were 25% greater compared to hosts only exposed to virus.3.Our second objective was to determine whether these patterns were generalizable to multiple amphibian species under more natural conditions. We conducted a semi-natural mesocosm experiment consisting of four larval amphibian hosts (gray treefrogs, American toads (Anaxyrus americanus), leopard frogs (Lithobates pipiens), and spring peepers (Pseudacris crucifer)) to examine how prior Echinoparyphium infection influenced ranavirus transmission within the community, using ranavirus-infected larval wood frogs (Lithobates sylvaticus) as source of ranavirus. Consistent with the laboratory experiment, we found that prior Echinoparyphium infection reduced ranaviral loads by 19 to 28% in three out of the four species.4.Collectively, these results suggest that macroparasite infection can reduce microparasite replication rates across multiple amphibian species, possibly through cross-reactive immunity. Although the immunological mechanisms driving this outcome are in need of further study, trematode infections appear to benefit hosts that are exposed to ranaviruses. Additionally, these results suggest that consideration of priority effects and timing of exposure are vital for understanding parasite interactions within hosts and disease outcomes.This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-20T01:50:41.104789-05:
      DOI: 10.1111/1365-2656.12665
       
  • Contact and contagion: Bighorn sheep demographic states vary in
           probability of transmission given contact
    • Authors: Kezia R. Manlove; E. Frances Cassirer, Raina K. Plowright, Paul C. Cross, Peter J. Hudson
      Abstract: 1.Understanding both contact and probability of transmission given contact are key to managing wildlife disease. However, wildlife disease research tends to focus on contact heterogeneity, in part because probability of transmission given contact is notoriously difficult to measure. Here we present a first step toward empirically investigating probability of transmission given contact in free-ranging wildlife.2.We used measured contact networks to test whether bighorn sheep demographic states vary systematically in infectiousness or susceptibility to Mycoplasma ovipneumoniae, an agent responsible for bighorn sheep pneumonia.3.We built covariates using contact network metrics, demographic information, and infection status, and used logistic regression to relate those covariates to lamb survival. The covariate set contained degree, a classic network metric describing node centrality, but also included covariates breaking the network metrics into subsets that differentiated between contacts with yearlings, ewes with lambs, and ewes without lambs, and animals with and without active infections.4.Yearlings, ewes with lambs, and ewes without lambs showed similar group membership patterns, but direct interactions involving touch occurred at a rate two orders of magnitude higher between lambs and reproductive ewes than between any classes of adults or yearlings, and one order of magnitude higher than direct interactions between lambs.5.Although yearlings and non-reproductive bighorn ewes regularly carried Mycoplasma ovipneumoniae, our models suggest that a contact with an infected reproductive ewe had approximately five times the odds of producing a lamb mortality event of an identical contact with an infected dry ewe or yearling. Consequently, management actions targeting infected animals might lead to unnecessary removal of young animals who carry pathogens but rarely transmit.6.This analysis demonstrates a simple logistic regression approach for testing a priori hypotheses about variation in odds of transmission given contact for free-ranging hosts, and may be broadly applicable for investigations in wildlife disease ecology.This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-20T01:45:30.590883-05:
      DOI: 10.1111/1365-2656.12664
       
  • Understanding how mammalian scavengers use information from avian
           scavengers: cue from above
    • Authors: Adam Kane; Corinne J. Kendall
      Abstract: Interspecific social information transfer can play a key role in many aspects of animal ecology from foraging to habitat selection to predator avoidance.Within scavenging communities, avian scavengers often act as producers and mammalian scavengers act as scroungers, but we predict that species-specific cueing will allow for mammalian scavengers to utilize particular avian scavenger species using preferred food sources similar to their own preferences.We use empirical and theoretic approaches to assess interactions between mammalian and avian scavengers in one of the most diverse scavenging guilds in Masai Mara National Reserve, Kenya.Using a spatially explicit model and data from experimental carcasses, we found evidence that mammals benefit from local enhancement provided by vultures and that mammalian-avian following patterns are consistent with the idea that species-specific cueing is occurring.Results suggest that ongoing population declines in avian scavengers may have significant impacts on mammalian scavengers and potentially create trophic cascades.This study showed that by using vultures, mammalian scavengers could find carcasses nearly twice as fast as if they had to search without seeing vultures landing and may cue to particular vulture species when deciding where to search. Declines in vultures may therefore have cascading effects on mammalian scavengers.
      PubDate: 2017-03-15T00:00:02.577926-05:
      DOI: 10.1111/1365-2656.12663
       
  • Hidden survival heterogeneity of three Common eider populations in
           response to climate fluctuations
    • Authors: Loreleï Guéry; Sébastien Descamps, Roger Pradel, Sveinn Are Hanssen, Kjell Einar Erikstad, Geir W. Gabrielsen, H. Grant Gilchrist, Joël Bêty
      Abstract: Understanding how individuals and populations respond to fluctuations in climatic conditions is critical to explain and anticipate changes in ecological systems. Most such studies focus on climate impacts on single populations without considering inter- and intra-population heterogeneity. However, comparing geographically dispersed populations limits the risk of faulty generalizations and helps to improve ecological and demographic models.We aimed to determine whether differences in migration tactics among and within populations would induce inter- or intra-population heterogeneity in survival in relation to winter climate fluctuations. Our study species was the Common eider (Somateria mollissima), a marine duck with a circumpolar distribution, which is strongly affected by climatic conditions during several phases of its annual cycle.Capture-mark-recapture data were collected in two arctic (northern Canada and Svalbard) and one subarctic (northern Norway) population over a period of 18, 15, and 29 years respectively. These three populations have different migration tactics and experience different winter climatic conditions. Using multi-event and mixture modelling, we assessed the association between adult female eider survival and winter conditions as measured by the North Atlantic Oscillation (NAO) index.We found that winter weather conditions affected the survival of female eiders from each of these three populations. However, different mechanisms seemed to be involved. Survival of the two migrating arctic populations was impacted directly by changes in the NAO, whereas the subarctic resident population was affected by the NAO with time lags of 2–3 years. Moreover, we found evidence for intra-population heterogeneity in the survival response to the winter NAO in the Canadian eider population, where individuals migrate to distinct wintering areas.Our results illustrate how individuals and populations of the same species can vary in their responses to climate variation. We suspect that the found variation in the survival response of birds to winter conditions is partly explained by differences in migration tactic. Detecting and accounting for inter- and intra-population heterogeneity will improve our predictions concerning the response of wildlife to global changes.The authors used a reverse procedure based on capture-recapture histories: using individual data in post-hoc analyses could help to confirm heterogeneity in demographic parameters, a priori suspected, and identify its potential sources. The approach could be extended to other species and disciplines whenever heterogeneity is suspected but exhaustive individual data are missing.
      PubDate: 2017-03-13T06:45:33.405252-05:
      DOI: 10.1111/1365-2656.12643
       
  • Field manipulations of resources mediate the transition from intraspecific
           competition to facilitation
    • Authors: Karin Svanfeldt; Keyne Monro, Dustin J. Marshall
      Abstract: Population density affects individual performance, though its effects are often mixed. For sessile species, increases in population density typically reduce performance. Still, cases of positive density-dependence do occur in sessile systems and demand explanation. The stress gradient hypothesis (SGH) predicts that under stressful conditions, positive effects of facilitation may outweigh the negative effects of competition.While some elements of the SGH are well studied, its potential to explain intraspecific facilitation has received little attention. Further, there have been questions regarding whether the SGH holds if the stressor is a resource. Most studies of interactions between the environment and intraspecific facilitation have relied on natural environmental gradients; manipulative studies are much rarer.To test the effects of intraspecific density and resources, we manipulated resource availability over natural population densities for the marine bryozoan Watersipora subtorquata.We found negative effects of density on colony performance in low resource environments, but mainly positive density-dependence in high resource environments. By adding resources, competition effects were reduced and the positive effects of facilitation were revealed.Our results suggest that resource availability mediates the relative strength of competition and facilitation in our system. We also suggest that intraspecific facilitation is more common than may be appreciated and that environmental variation may mediate the balance between negative and positive density-dependence.With this study, the authors explore the balance between positive and negative density dependence in a manipulative framework.
      PubDate: 2017-03-06T06:05:45.073832-05:
      DOI: 10.1111/1365-2656.12644
       
  • Many places called home: the adaptive value of seasonal adjustments in
           range fidelity
    • Authors: Alexandre Lafontaine; Pierre Drapeau, Daniel Fortin, Martin-Hugues St-Laurent
      Abstract: The vast majority of animal species display range fidelity, a space-use behaviour enhancing familiarity with local habitat features. While the fitness benefits of this behaviour have been demonstrated in a variety of taxa, some species or populations rather display infidelity, displacing their home range over time. Others, such as many ungulate species, show seasonal adjustments in their range fidelity to accommodate changes in the dominance of limiting factors or in the distribution of resources.Few empirical studies have explored the adaptive value of seasonal adjustments in range fidelity. Using boreal populations of woodland caribou (Rangifer tarandus caribou) as a biological model, we evaluated how range fidelity impacted individual performance during two seasons where juvenile and adult survival are limited by different predation pressures.Between 2004 and 2013, we monitored the survival, reproductive success, habitat selection and range fidelity of female caribou in the boreal forest of eastern Canada. Using resource selection functions, we assessed how seasonal range fidelity was linked to two fitness correlates: calf survival in summer and adult female survival in winter.Females displayed season-specific space use tactics: they selected previously used areas during calving and summer, but tended to shift their winter range from 1 year to the next. During calving and summer, range fidelity yielded relatively high fitness benefits, as females that did not lose their calf displayed stronger fidelity than females that did. In winter, however, adult survival was negatively linked to range fidelity, as females that survived selected areas further away from their seasonal range of the previous year than females that died.We provide one of the first evidences that making seasonal adjustments in range fidelity can be an adaptive behaviour influencing the spatial distribution of a threatened species. Assessing the seasonal nature of range fidelity tactics may improve our predictions of space use and associated fitness implications for species displaying this behaviour.The authors demonstrated that range fidelity impacted individual performance in caribou and showed that seasonal adjustments are an adaptive behaviour. Season-specific tactics yielded contrasted fitness benefits. Females that did not lose their calf displayed stronger fidelity in summer than females that did, while adult survival was negatively linked to fidelity in winter.
      PubDate: 2017-03-06T06:05:42.309706-05:
      DOI: 10.1111/1365-2656.12645
       
  • Parasites and a host's sense of smell: reduced chemosensory performance of
           
    • Authors: Ebrahim Lari; Cameron P. Goater, David K. Cone, Greg G. Pyle
      Abstract: Parasites residing within the central nervous system of their hosts have the potential to reduce various components of host performance, but such effects are rarely evaluated.We assessed the olfactory acuity of fathead minnows (Pimephales promelas) infected experimentally with the monogenean Dactylogyrus olfactorius, the adults of which live within the host's olfactory chambers.Olfactory acuity was compared between infected and uninfected hosts by assessing electro-olfactography (EOG) neural responses to chemical stimuli that indicate the presence of food (L-alanine) or the presence of conspecifics (taurocholic acid). We also compared differences in gross morphology of the olfactory epithelium in infected and uninfected minnows.Differences in EOG responses between infected and uninfected minnows to both cue types were non-significant at 30 days post-exposure. By days 60 and 90, coincident with a two times increase in parasite intensity in the olfactory chambers, the EOG responses of infected minnows were 70–90% lower than controls. When infected fish were treated with a parasiticide (Prazipro), olfactory acuity returned to control levels by day 7 post-treatment.The observed reduction in olfactory acuity is best explained by the reduced density of cilia covering the olfactory chambers of infected fish, or by the concomitant increase in the density of mucous cells that cover the olfactory chambers. These morphological changes are likely due to the direct effects of attachment and feeding by individual worms or by indirect effects associated with host responses. Our results show that infection of a commonly occurring monogenean in fathead minnows reduces olfactory acuity. Parasite-induced interference with olfactory performance may reduce a fish's ability to detect, or respond to, chemical cues originating from food, predators, competitors or mates.The development of a common parasite on the surface of the olfactory epithelium markedly reduces a minnow's ability to detect social and food-related cues. Parasite-induced reduction in olfactory acuity is far-reaching if it also interferes with a fish's ability to detect chemical cues from predators, competitors and mates.
      PubDate: 2017-03-02T11:30:30.809192-05:
      DOI: 10.1111/1365-2656.12642
       
  • Phylogenetic composition of host plant communities drives plant-herbivore
           food web structure
    • Authors: Martin Volf; Petr Pyszko, Tomokazu Abe, Martin Libra, Nela Kotásková, Martin Šigut, Rajesh Kumar, Ondřej Kaman, Philip T. Butterill, Jan Šipoš, Haruka Abe, Hiroaki Fukushima, Pavel Drozd, Naoto Kamata, Masashi Murakami, Vojtech Novotny
      Abstract: Insects tend to feed on related hosts. The phylogenetic composition of host plant communities thus plays a prominent role in determining insect specialization, food web structure, and diversity. Previous studies showed a high preference of insect herbivores for congeneric and confamilial hosts suggesting that some levels of host plant relationships may play more prominent role that others.We aim to quantify the effects of host phylogeny on the structure of quantitative plant-herbivore food webs. Further, we identify specific patterns in three insect guilds with different life histories and discuss the role of host plant phylogeny in maintaining their diversity.We studied herbivore assemblages in three temperate forests in Japan and the Czech Republic. Sampling from a canopy crane, a cherry picker and felled trees allowed a complete census of plant-herbivore interactions within three 0·1 ha plots for leaf chewing larvae, miners, and gallers. We analyzed the effects of host phylogeny by comparing the observed food webs with randomized models of host selection.Larval leaf chewers exhibited high generality at all three sites, whereas gallers and miners were almost exclusively monophagous. Leaf chewer generality dropped rapidly when older host lineages (5–80 myr) were collated into a single lineage but only decreased slightly when the most closely related congeneric hosts were collated. This shows that leaf chewer generality has been maintained by feeding on confamilial hosts while only a few herbivores were shared between more distant plant lineages and, surprisingly, between some congeneric hosts. In contrast, miner and galler generality was maintained mainly by the terminal nodes of the host phylogeny and dropped immediately after collating congeneric hosts into single lineages.We show that not all levels of host plant phylogeny are equal in their effect on structuring plant-herbivore food webs. In the case of generalist guilds, it is the phylogeny of deeper plant lineages that drives the food web structure whereas the terminal relationships play minor roles. In contrast, the specialization and abundance of monophagous guilds are affected mainly by the terminal parts of the plant phylogeny and do not generally reflect deeper host phylogeny.Here the authors quantify the effects of host plant phylogeny on canopy insect communities, identifying the levels of host phylogeny playing the major role in the structure of their food webs. The authors show that the specific role of host plant diversity and phylogenetic composition differs among herbivore guilds depending on their specialization.
      PubDate: 2017-03-02T08:00:26.639113-05:
      DOI: 10.1111/1365-2656.12646
       
  • The physiological costs of prey switching reinforce foraging
           specialization
    • Authors: Oliver E. Hooker; Travis E. Van Leeuwen, Colin E. Adams
      Abstract: Sympatric speciation is thought to be strongly linked to resource specialization with alternative resource use acting as a fundamental agent driving divergence. However, sympatric speciation through niche expansion is dependent on foraging specialization being consistent over space and time.Standard metabolic rate is the minimal maintenance metabolic rate of an ectotherm in a post-absorptive and inactive state and can constitute a significant portion of an animal's energy budget; thus, standard metabolic rate and growth rate are two measures frequently used as an indication of the physiological performance of individuals. Physiological adaptations to a specific diet may increase the efficiency with which it is utilized, but may have an increased cost associated with switching diets, which may result in a reduced standard metabolic rate and growth rate.In this study, we use the diet specialization often seen in polymorphic Arctic charr (Salvelinus alpinus) populations to study the effects of different prey on standard metabolic rate and growth rate as well as the effects that early prey specialization may have on the ability to process other prey types efficiently.We found a significant effect of prey type on standard metabolic rate and growth rate. Furthermore, we found evidence of diet specialization with all fish maintaining a standard metabolic rate and growth rate lower than expected when fed on a diet different to which they were raised, possibly due to a maladaptation in digestion of alternative prey items.Our results show that early diet specialization may be reinforced by the elevated costs of prey switching, thus promoting the process of resource specialization during the incipient stages of sympatric divergence.This study increases our understanding of the role of physiology in diverging populations. Morphological differences are frequently shown to influence energy intake, a major driver of divergence. The authors show that differences in digestive anatomy are equally important in reinforcing dietary specializations. However, these types of cryptic adaptations are often overlooked.
      PubDate: 2017-03-01T06:06:21.788754-05:
      DOI: 10.1111/1365-2656.12632
       
  • Land-use type and intensity differentially filter traits in above- and
           below-ground arthropod communities
    • Authors: Klaus Birkhofer; Martin M. Gossner, Tim Diekötter, Claudia Drees, Olga Ferlian, Mark Maraun, Stefan Scheu, Wolfgang W. Weisser, Volkmar Wolters, Susanne Wurst, Andrey S. Zaitsev, Henrik G. Smith
      Abstract: Along with the global decline of species richness goes a loss of ecological traits. Associated biotic homogenization of animal communities and narrowing of trait diversity threaten ecosystem functioning and human well-being. High management intensity is regarded as an important ecological filter, eliminating species that lack suitable adaptations. Below-ground arthropods are assumed to be less sensitive to such effects than above-ground arthropods.Here, we compared the impact of management intensity between (grassland vs. forest) and within land-use types (local management intensity) on the trait diversity and composition in below- and above-ground arthropod communities.We used data on 722 arthropod species living above-ground (Auchenorrhyncha and Heteroptera), primarily in soil (Chilopoda and Oribatida) or at the interface (Araneae and Carabidae).Our results show that trait diversity of arthropod communities is not primarily reduced by intense local land use, but is rather affected by differences between land-use types. Communities of Auchenorrhyncha and Chilopoda had significantly lower trait diversity in grassland habitats as compared to forests. Carabidae showed the opposite pattern with higher trait diversity in grasslands. Grasslands had a lower proportion of large Auchenorrhyncha and Carabidae individuals, whereas Chilopoda and Heteroptera individuals were larger in grasslands. Body size decreased with land-use intensity across taxa, but only in grasslands. The proportion of individuals with low mobility declined with land-use intensity in Araneae and Auchenorrhyncha, but increased in Chilopoda and grassland Heteroptera. The proportion of carnivorous individuals increased with land-use intensity in Heteroptera in forests and in Oribatida and Carabidae in grasslands.Our results suggest that gradients in management intensity across land-use types will not generally reduce trait diversity in multiple taxa, but will exert strong trait filtering within individual taxa. The observed patterns for trait filtering in individual taxa are not related to major classifications into above- and below-ground species. Instead, ecologically different taxa resembled each other in their trait diversity and compositional responses to land-use differences. These previously undescribed patterns offer an opportunity to develop management strategies for the conservation of trait diversity across taxonomic groups in permanent grassland and forest habitats.The strong effects of land-use type and intensity on trait composition suggest that conversion of forest to grassland and management intensification within land-use types will lead to filtering of traits in several above- and below-ground arthropod taxa. These losses of traits are not predictable based on simple classifications into above- or below-ground arthropod taxa.
      PubDate: 2017-02-28T08:40:25.601058-05:
      DOI: 10.1111/1365-2656.12641
       
  • The changing contribution of top-down and bottom-up limitation of
           mesopredators during 220 years of land use and climate change
    • Authors: Marianne Pasanen-Mortensen; Bodil Elmhagen, Harto Lindén, Roger Bergström, Märtha Wallgren, Ype Velde, Sara A.O. Cousins
      Abstract: Apex predators may buffer bottom-up driven ecosystem change, as top-down suppression may dampen herbivore and mesopredator responses to increased resource availability. However, theory suggests that for this buffering capacity to be realized, the equilibrium abundance of apex predators must increase. This raises the question: will apex predators maintain herbivore/mesopredator limitation, if bottom-up change relaxes resource constraints'Here, we explore changes in mesopredator (red fox Vulpes vulpes) abundance over 220 years in response to eradication and recovery of an apex predator (Eurasian lynx Lynx lynx), and changes in land use and climate which are linked to resource availability.A three-step approach was used. First, recent data from Finland and Sweden were modelled to estimate linear effects of lynx density, land use and winter temperature on fox density. Second, lynx density, land use and winter temperature was estimated in a 22 650 km2 focal area in boreal and boreo-nemoral Sweden in the years 1830, 1920, 2010 and 2050. Third, the models and estimates were used to project historic and future fox densities in the focal area.Projected fox density was lowest in 1830 when lynx density was high, winters cold and the proportion of cropland low. Fox density peaked in 1920 due to lynx eradication, a mesopredator release boosted by favourable bottom-up changes – milder winters and cropland expansion. By 2010, lynx recolonization had reduced fox density, but it remained higher than in 1830, partly due to the bottom-up changes. Comparing 1830 to 2010, the contribution of top-down limitation decreased, while environment enrichment relaxed bottom-up limitation. Future scenarios indicated that by 2050, lynx density would have to increase by 79% to compensate for a projected climate-driven increase in fox density.We highlight that although top-down limitation in theory can buffer bottom-up change, this requires compensatory changes in apex predator abundance. Hence apex predator recolonization/recovery to historical levels would not be sufficient to compensate for widespread changes in climate and land use, which have relaxed the resource constraints for many herbivores and mesopredators. Variation in bottom-up conditions may also contribute to context dependence in apex predator effects.In this study, the authors use present-day data to project mesopredator abundance over 220 years in relation to changes in apex predator abundance, land use and climate. They conclude that the contribution of apex predators in limiting mesopredators may decrease when changes in bottom-up drivers causes environment enrichment. Photo: Bodil Elmhagen.
      PubDate: 2017-02-28T04:50:32.861307-05:
      DOI: 10.1111/1365-2656.12633
       
  • Competitor phenology as a social cue in breeding site selection
    • Authors: Jelmer M. Samplonius; Christiaan Both
      Abstract: Predicting habitat quality is a major challenge for animals selecting a breeding patch, because it affects reproductive success. Breeding site selection may be based on previous experience, or on social information from the density and success of competitors with an earlier phenology.Variation in animal breeding phenology is often correlated with variation in habitat quality. Generally, animals breed earlier in high-quality habitats that allow them to reach a nutritional threshold required for breeding earlier or avoid nest predation. In addition, habitat quality may affect phenological overlap between species and thereby interspecific competition. Therefore, we hypothesized that competitor breeding phenology can be used as social cue by settling migrants to locate high-quality breeding sites.To test this hypothesis, we experimentally advanced and delayed hatching phenology of two resident tit species on the level of study plots and studied male and female settlement patterns of migratory pied flycatchers Ficedula hypoleuca. The manipulations were assigned at random in two consecutive years, and treatments were swapped between years in sites that were used in both years.In both years, males settled in equal numbers across treatments, but later arriving females avoided pairing with males in delayed phenology plots. Moreover, male pairing probability declined strongly with arrival date on the breeding grounds.Our results demonstrate that competitor phenology may be used to assess habitat quality by settling migrants, but we cannot pinpoint the exact mechanism (e.g. resource quality, predation pressure or competition) that has given rise to this pattern.In addition, we show that opposing selection pressures for arrival timing may give rise to different social information availabilities between sexes. We discuss our findings in the context of climate warming, social information use and the evolution of protandry in migratory animals.Climate change differentially affects phenologies of resident and migratory birds, which may have repercussions for interspecific interactions. Here, the authors experimentally show that reproductive timing of resident tits affect settlement patterns of migratory pied flycatchers. Heterospecific information use may therefore be affected by differential phenological changes in response to climate warming.
      PubDate: 2017-02-27T09:55:42.278289-05:
      DOI: 10.1111/1365-2656.12640
       
  • Low migratory connectivity is common in long-distance migrant birds
    • Authors: Tom Finch; Simon J. Butler, Aldina M. A. Franco, Will Cresswell
      Abstract: Estimating how much long-distance migrant populations spread out and mix during the non-breeding season (migratory connectivity) is essential for understanding and predicting population dynamics in the face of global change.We quantify variation in population spread and inter-population mixing in long-distance, terrestrial migrant land-bird populations (712 individuals from 98 populations of 45 species, from tagging studies in the Neotropic and Afro-Palearctic flyways). We evaluate the Mantel test as a metric of migratory connectivity, and explore the extent to which variance in population spread can be explained simply by geography.The mean distance between two individuals from the same population during the non-breeding season was 743 km, covering 10–20% of the maximum width of Africa/South America. Individuals from different breeding populations tended to mix during the non-breeding season, although spatial segregation was maintained in species with relatively large non-breeding ranges (and, to a lesser extent, those with low population-level spread). A substantial amount of between-population variation in population spread was predicted simply by geography, with populations using non-breeding zones with limited land availability (e.g. Central America compared to South America) showing lower population spread.The high levels of population spread suggest that deterministic migration tactics are not generally adaptive; this makes sense in the context of the recent evolution of the systems, and the spatial and temporal unpredictability of non-breeding habitat.The conservation implications of generally low connectivity are that the loss (or protection) of any non-breeding site will have a diffuse but widespread effect on many breeding populations. Although low connectivity should engender population resilience to shifts in habitat (e.g. due to climate change), we suggest it may increase susceptibility to habitat loss. We hypothesize that, because a migrant species cannot adapt to both simultaneously, migrants generally may be more susceptible to population declines in the face of concurrent anthropogenic habitat and climate change.This study gathers data from migrant land-bird tracking studies from two major global flyways, summarizing the migration of 712 individuals of 45 species. In general, there was limited evidence for population-specific wintering areas; on average, two individuals tracked from the same breeding population wintered more than 700 km apart.
      PubDate: 2017-02-27T09:55:31.657819-05:
      DOI: 10.1111/1365-2656.12635
       
  • Density-dependent selection on mate search and evolution of Allee effects
    • Authors: Luděk Berec; Andrew M. Kramer, Veronika Bernhauerová, John M. Drake
      Abstract: Sexually reproducing organisms require males and females to find each other. Increased difficulty of females finding mates as male density declines is the most frequently reported mechanism of Allee effects in animals. Evolving more effective mate search may alleviate Allee effects, but may depend on density regimes a population experiences. In particular, high density populations may evolve mechanisms that induce Allee effects which become detrimental when populations are reduced and maintained at a low density.We develop an individual-based, eco-genetic model to study how mating systems and fitness trade-offs interact with changes in population density to drive evolution of the rate at which males or females search for mates. Finite mate search rate triggers Allee effects in our model and we explore how these Allee effects respond to such evolution.We allow a population to adapt to several population density regimes and examine whether high-density populations are likely to reverse adaptations attained at low densities. We find density-dependent selection in most of scenarios, leading to search rates that result in lower Allee thresholds in populations kept at lower densities. This mainly occurs when fecundity costs are imposed on mate search, and provides an explanation for why Allee effects are often observed in anthropogenically rare species.Optimizing selection, where the attained trait value minimizes the Allee threshold independent of population density, depended on the trade-off between search and survival, combined with monogamy when females were searching. Other scenarios led to runaway selection on the mate search rate, including evolutionary suicide. Trade-offs involved in mate search may thus be crucial to determining how density influences the evolution of Allee effects.Previous studies did not examine evolution of a trait related to the strength of Allee effects under density variation. We emphasize the crucial role that mating systems, fitness trade-offs, and the evolving sex have in determining the density threshold for population persistence, in particular since evolution need not always take the Allee threshold to its minimum value.This article is protected by copyright. All rights reserved.
      PubDate: 2017-02-27T05:07:24.476946-05:
      DOI: 10.1111/1365-2656.12662
       
  • Immune priming specificity within and across generations reveals the range
           of pathogens affecting evolution of immunity in an insect
    • Authors: Julien Dhinaut; Manon Chogne, Yannick Moret
      Abstract: 1.Many organisms can improve their immune response as a function of their immunological experience or that of their parents. This phenomenon, called immune priming, has likely evolved from repetitive challenges by the same pathogens during the host lifetime or across generation.2.All pathogens may not expose host to the same probability of re-infection and immune priming is expected to evolve from pathogens exposing the host to the greatest probability of re-infection. Under this hypothesis, the priming response to these pathogens should be specifically more efficient and less costly than to others.3.We examined the specificity of immune priming within and across generations in the mealworm beetle, Tenebrio molitor, by comparing survival of individuals to infection with bacteria according to their own immunological experience or that of their mother with these bacteria.4.We found that insects primed with Gram-positive bacteria became highly protected against both Gram-positive and Gram-negative bacterial infections, mainly due to an induced persistent antibacterial response, which did not exist in insects primed with Gram-negative bacteria. Insects primed with Gram-positive bacteria also exhibited enhanced concentration of hemocytes, but their implication in acquired resistance was not conclusive because of the persistent antibacterial activity in the hemolymph. Offspring maternally primed with Gram-positive and Gram-negative bacteria exhibited similarly improved immunity, whatever the bacteria used for the infection. Such maternal protection was costly in the larval development of offspring, but this cost was lower for offspring maternally primed with Gram-positive bacteria.5.While T. molitor can develop some levels of primed response to Gram-negative bacteria, the priming response to Gram-positive bacteria was more efficient and less costly. We concluded that Gram-positive bacterial pathogens were of paramount importance in the evolution of immune priming in this insect species.This article is protected by copyright. All rights reserved.
      PubDate: 2017-02-27T05:00:22.430441-05:
      DOI: 10.1111/1365-2656.12661
       
  • Metabolic theory predicts animal self-thinning
    • Authors: Tomas Jonsson
      Abstract: The metabolic theory of ecology (MTE) predicts observed patterns in ecology based on metabolic rates of individuals. The theory is influential but also criticized for a lack of firm empirical evidence confirming MTE's quantitative predictions of processes, e.g. outcome of competition, at population or community level.Self-thinning is a well-known population level phenomenon among plants, but a much less studied phenomenon in animal populations and no consensus exists on what a universal thinning slope for animal populations might be, or if it exists.The goal of this study was to use animal self-thinning as a tool to test population-level predictions from MTE, by analysing (i) if self-thinning can be induced in populations of house crickets (Acheta domesticus) and (ii) if the resulting thinning trajectories can be predicted from metabolic theory, using estimates of the species-specific metabolic rate of A. domesticus.I performed a laboratory study where the growth of A. domesticus was followed, from hatching until emergence as adults, in 71 cohorts of five different starting densities.Ninety-six per cent of all cohorts in the three highest starting densities showed evidence of self-thinning, with estimated thinning slopes in general being remarkably close to that expected under metabolic constraints: A cross-sectional analysis of all data showing evidence of self-thinning produced an ordinary least square (OLS) slope of −1·11, exactly that predicted from specific metabolic allometry of A. domesticus. This result is furthermore supported by longitudinal analyses, allowing for independent responses within cohorts, producing a mean OLS slope across cohorts of −1·13 and a fixed effect linear mixed effects models slope of −1·09. Sensitivity analysis showed that these results are robust to how the criterion for on-going self-thinning was defined. Finally, also as predicted by metabolic theory, temperature had a negative effect on the thinning intercept, producing an estimate of the activation energy identical to that suggested by MTE.This study demonstrates a direct link between the metabolic rate of individuals and a population-level ecological process and as such provides strong support for research that aims to integrate body mass, via its effect on metabolism, consumption and competition, into models of populations and communities.This study establishes metabolic-rate-based animal self-thinning as a fact and provides experimental evidence for a direct link between an ecological process at the population level and the metabolic rate of the individuals involved. These findings provide experimental support for the metabolic theory of ecology, where the metabolic exponent of individual species is taken into account to provide quantitative predictions of ecological processes.
      PubDate: 2017-02-23T06:05:47.581808-05:
      DOI: 10.1111/1365-2656.12638
       
  • Warmer temperatures reduce the influence of an important keystone predator
    • Authors: Chiara Bonaviri; Michael Graham, Paola Gianguzza, Nick T. Shears
      Abstract: Predator–prey interactions may be strongly influenced by temperature variations in marine ecosystems. Consequently, climate change may alter the importance of predators with repercussions for ecosystem functioning and structure.In North-eastern Pacific kelp forests, the starfish Pycnopodia helianthoides is known to be an important predator of the purple sea urchin Strongylocentrotus purpuratus. Here we investigated the influence of water temperature on this predator–prey interaction by: (i) assessing the spatial distribution and temporal dynamics of both species across a temperature gradient in the northern Channel Islands, California, and (ii) investigating how the feeding rate of P. helianthoides on S. purpuratus is affected by temperature in laboratory tests.On average, at sites where mean annual temperatures were 16 °C (equivalent to summer temperatures at sites where P. helianthoides were rare) reduced predation rates regardless of predator and prey sizes, although larger sea urchins were consumed only by large starfishes.These results clearly demonstrate that the effect of P. helianthoides on S. purpuratus is strongly mediated by temperature, and that the local abundance and predation rate of P. helianthoides on sea urchins will likely decrease with future warming. A reduction in top-down control on sea urchins, combined with other expected impacts of climate change on kelp, poses significant risks for the persistence of kelp forests in the future.The abundance and predation rate of the starfish Pycnopodia helianthoides was reduced under warm conditions allowing the sea urchin Strongylocentrotus purpuratus to graze down kelp forests. This indicates that the importance of this keystone predator in structuring kelp forest communities will be reduced with ocean warming.
      PubDate: 2017-02-23T06:05:45.027192-05:
      DOI: 10.1111/1365-2656.12634
       
  • Predators regulate prey species sorting and spatial distribution in
           microbial landscapes
    • Authors: George Livingston; Kayoko Fukumori, Diogo B. Provete, Masanobu Kawachi, Noriko Takamura, Mathew A. Leibold
      Abstract: The role of predation in determining the metacommunity assembly model of prey communities is understudied relative to that of interspecific competition among prey. Previous work on metacommunity dynamics of competing species has shown that sorting by habitat patch type and spatial patterning can be affected by disturbances.Microcosms offer a useful model system to test the effect of multi-trophic interactions and disturbance on metacommunity dynamics. Here, we investigated the potential role of predators in enhancing or disrupting sorting and spatial pattern among prey in experimental landscapes.We exposed multi-trophic protist microcosm landscapes with one predator, two competing prey, two patch resource types, and localized dispersal to three disturbance regimes (none, low, and high). Then, we used variation partitioning and spatial clustering analysis to analyse the results.In contrast with previous experiments that did not manipulate predators, we found that patch type did not structure prey communities very well. Instead, we found that it was the distribution of the predator that most strongly predicted the composition of the prey community.The predator impacted species sorting by (1) preferentially consuming one prey, thereby acting as a strong local environmental driver, and by (2) indirectly magnifying the impact of patch food resources on the less preferred prey. The predator also enhanced spatial signal in the prey community because of its limited dispersal.Our results indicate that predators can strongly influence prey species sorting and spatial patterning in metacommunities in ways that would otherwise be attributed to stochastic effects, such as dispersal limitation or demographic drift. Therefore, whenever possible, predators should be explicitly included as separate explanatory factors in variation partitioning analyses.Predators can strongly influence prey species sorting and spatial patterning in metacommunities in ways that would otherwise be attributed to stochastic effects, such as dispersal limitation or demographic drift.
      PubDate: 2017-02-22T04:30:41.821343-05:
      DOI: 10.1111/1365-2656.12639
       
  • Reproductive success is driven by local site fidelity despite stronger
           specialisation by individuals for large-scale habitat preference
    • Authors: Samantha Clare Patrick; Henri Weimerskirch
      Abstract: There is widespread evidence that within populations, specialists and generalists can coexist and this is particularly prevalent in marine ecosystems, where foraging specialisations are evident.While individuals may limit niche overlap by consistently foraging in specific areas, site fidelity may also emerge as an artefact of habitat choice, but both drivers and fitness consequences of site fidelity are poorly understood.Here, we examine an individual metric of site and habitat fidelity, using tracking data collected over 11 years for black-browed albatrosses (Thalassarche melanophris). Fidelity was calculated as the similarity between pairs of foraging zones, quantifying measures for within and between years. Foraging areas were identified using area-restricted search, defined as periods during which birds decrease speed and increase turning.Our results demonstrate that birds were considerably more specialised in the habitat in which they forage than the exact location they use within years, and there was a similar pattern between years. However, despite this, it was site fidelity that explained reproductive success. Within a single year, females which were more faithful to a specific location had higher reproductive success than non-specialists, and between years there was a tendency for both sexes.Our results suggest that black-browed albatrosses are highly faithful in their foraging habitat but it is rather site fidelity that is more clearly associated with reproductive success.This study demonstrates strong habitat fidelity but that fitness is driven by site fidelity in black-browed albatrosses.
      PubDate: 2017-02-22T04:20:50.612362-05:
      DOI: 10.1111/1365-2656.12636
       
  • Nitrogen deposition cancels out exotic earthworm effects on plant-feeding
           nematode communities
    • Authors: Yuanhu Shao; Weixin Zhang, Nico Eisenhauer, Tao Liu, Yanmei Xiong, Chenfei Liang, Shenglei Fu
      Abstract: 1.The activity and spread of exotic earthworms often are spatially correlated with N deposition because both arise from human activities. Exotic earthworms, in turn, can also greatly affect soil abiotic and biotic properties, as well as related ecological processes. Previous studies showed, for example, that earthworms can counteract the detrimental effects of plant-feeding nematodes on plant growth. However, potential interactive effects of N deposition and exotic earthworms on ecosystems are poorly understood.2.We explored the changes in density of plant-feeding nematodes in response to the presence of exotic earthworms, and whether these changes are altered by elevated N deposition in a two-factorial field mesocosm experiment at the Heshan National Field Research Station of Forest Ecosystem, in southern China.3.Our results show that earthworm addition marginally significantly increased the density of exotic earthworms and significantly increased the mass of earthworm casts. The total density of plant-feeding nematodes was not significantly affected by exotic earthworms or N deposition. However, exotic earthworms tended to increase the density of plant-feeding nematode taxa that are less detrimental to plant growth (r-strategists), while they significantly reduced the density of more harmful plant-feeding nematodes (K-strategists). Importantly, these earthworm effects were restricted to the ambient N deposition treatment, and elevated N deposition cancelled out the earthworm effect. Although exotic earthworms and N deposition interactively altered foliar N:P ratio in the target tree species, this did not result in significant changes in shoot and root biomass in the short term.4.Overall, our study indicates that N deposition can cancel out exotic earthworm-induced reductions in the density of harmful plant-feeding nematodes. These results suggest that anthropogenic N deposition can alter biotic interactions between exotic and native soil organisms with potential implications for ecosystem functioning.This article is protected by copyright. All rights reserved.
      PubDate: 2017-02-21T22:50:25.213879-05:
      DOI: 10.1111/1365-2656.12660
       
  • Sex Differences and Allee Effects Shape the Dynamics of Sex-Structured
           Invasions
    • Authors: Allison K. Shaw; Hanna Kokko, Michael G. Neubert
      Abstract: SummaryThe rate at which a population grows and spreads can depend on individual behaviour and interactions with others. In many species with two sexes, males and females differ in key life history traits (e.g. growth, survival, dispersal), which can scale up to affect population rates of growth and spread. In sexually reproducing species, the mechanics of locating mates and reproducing successfully introduce further complications for predicting the invasion speed (spread rate), as both can change nonlinearly with density.Most models of population spread are based on one sex, or include limited aspects of sex differences. Here we ask whether and how the dynamics of finding mates interact with sex-specific life history traits to influence the rate of population spread.We present a hybrid approach for modelling invasions of populations with two sexes that links individual-level mating behaviour (in an individual-based model) to population-level dynamics (in an integrodifference equation model).We find that limiting the amount of time during which individuals can search for mates causes a demographic Allee effect which can slow, delay or even prevent an invasion. Furthermore, any sex-based asymmetries in life history or behaviour (skewed sex ratio, sex-biased dispersal, sex-specific mating behaviours) amplify these effects. In contrast, allowing individuals to mate more than once ameliorates these effects, enabling polygynandrous populations to invade under conditions where monogamously mating populations would fail to establish.We show that details of individuals’ mating behaviour can impact the rate of population spread. Based on our results, we propose a stricter definition of a mate-finding Allee effect, which is not met by the commonly used minimum mating function. Our modelling approach, which links individual and population-level dynamics in a single model, may be useful for exploring other aspects of individual behaviour that are thought to impact the rate of population spread.This article is protected by copyright. All rights reserved.
      PubDate: 2017-02-20T21:55:22.697351-05:
      DOI: 10.1111/1365-2656.12658
       
  • Caching reduces kleptoparasitism in a solitary, large felid
    • Authors: Guy A. Balme; Jennifer R. B. Miller, Ross T. Pitman, Luke T. B. Hunter
      Abstract: Food caching is a common strategy used by a diversity of animals, including carnivores, to store and/or secure food. Despite its prevalence, the drivers of caching behaviour, and its impacts on individuals, remain poorly understood, particularly for short-term food cachers.Leopards Panthera pardus exhibit a unique form of short-term food caching, regularly hoisting, storing, and consuming prey in trees. We explored the factors motivating such behaviour among leopards in the Sabi Sand Game Reserve, South Africa, associated with four not mutually exclusive hypotheses: food-perishability, consumption-time, resource-pulse, and kleptoparasitism-avoidance.Using data from 2,032 prey items killed by 104 leopards from 2013–2015, we built generalized linear mixed models to examine how hoisting behaviour, feeding time, and the likelihood of a kill being kleptoparasitised varied with leopard sex and age, prey size and vulnerability, vegetation, elevation, climate, and the short-term (immediate presence) and long-term (species density) risk posed by dominant competitors.Leopards hoisted 51% of kills. They were more likely to hoist kills of an intermediate size, outside of a resource pulse, and in response to the presence of some competitors. Hoisted kills were also fed on for longer than non-hoisted kills. At least 21% of kills were kleptoparasitised, mainly by spotted hyaenas Crocuta crocuta. Kills were more likely to be kleptoparasitised at lower temperatures and if prey were larger, not hoisted, and in areas where the risk of encountering hyaenas was greatest. Female leopards that suffered higher rates of kleptoparasitism exhibited lower annual reproductive success than females that lost fewer kills.Our results strongly support the kleptoparasitism-avoidance hypothesis and suggest hoisting is a key adaptation that enables leopards to coexist sympatrically with high densities of competitors. We further argue that leopards may select smaller-sized prey than predicted by optimal foraging theory, to balance trade-offs between kleptoparasitic losses and the energetic gains derived from killing larger prey.Although caching may provide the added benefits of delaying food perishability and enabling consumption over an extended period, the behaviour primarily appears to be a strategy for leopards, and possibly other short-term cachers, to reduce the risks of kleptoparasitism. This article is protected by copyright. All rights reserved.
      PubDate: 2017-02-19T20:50:27.643215-05:
      DOI: 10.1111/1365-2656.12654
       
  • Range shifting species reduce phylogenetic diversity in high latitude
           communities via competition
    • Authors: Robert Fitt; Lesley T. Lancaster
      Abstract: Under anthropogenic climate change, many species are expanding their ranges to higher latitudes and altitudes, resulting in novel species interactions. The consequences of these range shifts for native species, patterns of local biodiversity, and community structure in high latitude ecosystems are largely unknown but critical to understand in light of widespread poleward expansions by many warm-adapted generalists.Using niche modelling, phylogenetic methods, and field and laboratory studies, we investigated how colonisation of Scotland by a range expanding damselfly, Ischnura elegans, influences patterns of competition and niche shifts in native damselfly species, and changes in phylogenetic community structure.Colonization by I. elegans was associated with reduced population density and niche shifts in the resident species least related to I. elegans (Lestes sponsa), reflecting enhanced competition. Furthermore, communities colonized by I. elegans exhibited phylogenetic underdispersion, reflecting patterns of relatedness and competition.Our results provide a novel example of a potentially general mechanism whereby climate change-mediated range shifts can reduce phylogenetic diversity within high latitude communities, if colonising species are typically competitively superior to members of native communities that are least-closely-related to the coloniser.This article is protected by copyright. All rights reserved.
      PubDate: 2017-02-19T20:50:22.399318-05:
      DOI: 10.1111/1365-2656.12655
       
  • Population dynamics of wild rodents induce stochastic fadeouts of a
           zoonotic pathogen
    • Authors: Giorgio Guzzetta; Valentina Tagliapietra, Sarah E. Perkins, Heidi C. Hauffe, Piero Poletti, Stefano Merler, Annapaola Rizzoli
      Abstract: Stochastic processes play an important role in the infectious disease dynamics of wildlife, especially in species subject to large population oscillations.Here we study the case of a free ranging population of yellow-necked mice (Apodemus flavicollis) in northern Italy, where circulation of Dobrava-Belgrade hantavirus (DOBV) has been detected intermittently since 2001, until an outbreak emerged in 2010.We analyzed the transmission dynamics of the recent outbreak using a computational model that accounts for seasonal changes of the host population and territorial behavior. Model parameters were informed by capture-mark-recapture data collected over 14 years and longitudinal seroprevalence data from 2010 to 2013.The intermittent observation of DOBV before 2010 can be interpreted as repeated stochastic fadeouts after multiple introductions of infectious rodents migrating from neighboring areas. We estimated that only 20% of introductions in a naïve host population results in sustained transmission after two years, despite an effective reproduction number well above the epidemic threshold (mean 4.5, 95% credible intervals, CI: 0.65-15.8). Following the 2010 outbreak, DOBV has become endemic in the study area, but we predict a constant probability of about 4.7% per year that infection dies out, following large population drops in winter. In the absence of stochastic fadeout, viral prevalence is predicted to continue its growth to an oscillating equilibrium around a value of 24% (95% CI: 3-57%).We presented an example of invasion dynamics of a zoonotic virus where stochastic fadeout have played a major role and may induce future extinction of the endemic infection. This article is protected by copyright. All rights reserved.
      PubDate: 2017-02-19T20:45:23.095352-05:
      DOI: 10.1111/1365-2656.12653
       
  • Life-history strategy determines constraints on immune function
    • Authors: Benjamin J. Parker; Seth M. Barribeau, Alice M. Laughton, Lynn H. Griffin, Nicole M. Gerardo
      Abstract: 1)Determining the factors governing investment in immunity is critical for understanding host-pathogen ecological and evolutionary dynamics. Studies often consider disease resistance in the context of life-history theory, with the expectation that investment in immunity will be optimized in anticipation of disease risk. Immunity, however, is constrained by context-dependent fitness costs. How the costs of immunity vary across life-history strategies has yet to be considered.2)Pea aphids are typically unwinged but produce winged offspring in response to high population densities and deteriorating conditions. This is an example of polyphenism, a strategy used by many organisms to adjust to environmental cues. The goal of this study was to examine the relationship between the fitness costs of immunity, pathogen resistance, and the strength of an immune response across aphid morphs that differ in life-history strategy but are genetically identical.3)We measured fecundity of winged and unwinged aphids challenged with a heat-inactivated fungal pathogen, and found that immune costs are limited to winged aphids. We hypothesized that these costs reflect stronger investment in immunity in anticipation of higher disease risk, and that winged aphids would be more resistant due to a stronger immune response. However, producing wings is energetically expensive. This guided an alternative hypothesis—that investing resources into wings could lead to a reduced capacity to resist infection.4)We measured survival and pathogen load after live fungal infection, and we characterized the aphid immune response to fungi by measuring immune cell concentration and gene expression. We found that winged aphids are less resistant and mount a weaker immune response than unwinged aphids, demonstrating that winged aphids pay higher costs for a less effective immune response.5)Our results show that polyphenism is an understudied factor influencing the expression of immune costs. More generally, our work shows that in addition to disease resistance, the costs of immunity vary between individuals with different life-history strategies. We discuss the implications of these findings for understanding how organisms invest optimally in immunity in light of context-dependent constraints.This article is protected by copyright. All rights reserved.
      PubDate: 2017-02-17T01:40:24.372905-05:
      DOI: 10.1111/1365-2656.12657
       
  • Detecting signals of chronic shedding to explain pathogen persistence:
           Leptospira interrogans in California sea lions
    • Authors: M. G. Buhnerkempe; K. C. Prager, C. C. Strelioff, D. J. Greig, J. L. Laake, S. R. Melin, R. L. DeLong, F. M. D. Gulland, J. O. Lloyd-Smith
      Abstract: Identifying mechanisms driving pathogen persistence is a vital component of wildlife disease ecology and control. Asymptomatic, chronically infected individuals are an oft-cited potential reservoir of infection but demonstrations of the importance of chronic shedding to pathogen persistence at the population level remain scarce.Studying chronic shedding using commonly collected disease data is hampered by numerous challenges, including short-term surveillance that focuses on single epidemics and acutely ill individuals, the subtle dynamical influence of chronic shedding relative to more obvious epidemic drivers, and poor ability to differentiate between the effects of population prevalence of chronic shedding versus intensity and duration of chronic shedding in individuals.We use chronic shedding of Leptospira interrogans serovar Pomona in California sea lions (Zalophus californianus) as a case study to illustrate how these challenges can be addressed. Using leptospirosis-induced strands as a measure of disease incidence, we fit models with and without chronic shedding, and with different seasonal drivers, to determine the timescale over which chronic shedding is detectable and the interactions between chronic shedding and seasonal drivers needed to explain persistence and outbreak patterns.Chronic shedding can enable persistence of L. interrogans within the sea lion population. However, the importance of chronic shedding was only apparent when surveillance data included at least two outbreaks and the intervening inter-epidemic trough during which fadeout of transmission was most likely. Seasonal transmission, as opposed to seasonal recruitment of susceptibles, was the dominant driver of seasonality in this system, and both seasonal factors had limited impact on long-term pathogen persistence.We show that the temporal extent of surveillance data can have a dramatic impact on inferences about population processes, where the failure to identify both short- and long-term ecological drivers can have cascading impacts on understanding higher-order ecological phenomena, such as pathogen persistence.This article is protected by copyright. All rights reserved.
      PubDate: 2017-02-16T15:35:25.385545-05:
      DOI: 10.1111/1365-2656.12656
       
  • To graze or gorge: consistency and flexibility of individual foraging
           tactics in tits
    • Authors: Nicole D. Milligan; Reinder Radersma, Ella F. Cole, Ben C. Sheldon
      Abstract: An individual's foraging behaviour and time allocated to feeding have direct consequences for its fitness. Despite much research on population-level foraging decisions, few studies have investigated individual differences in fine-scale daily foraging patterns amongst wild animals.Here, we explore the consistency and plasticity of feeding tactics of individual great tits (Parus major) and blue tits (Cyanistes caeruleus), using a grid of 65 automated feeding stations in a 385-ha woodland, during three winters. We use a principal component analysis to describe individual variation in six feeding parameters and examine how these differences covary with dominance-linked attributes (species, age and sex), the personality trait ‘exploration behaviour’, distance to territory, and local competition intensity.Analysis of 933,086 feeder visits by 3,134 individuals revealed that the majority of variation in the timing of feeding was explained by two principal components. PC1 (‘binge-eating’), accounting for 38% of variation, captured temporal clustering of feeding, with high repeatability both within and between years (r range: 0.42 to 0.55). PC2 (‘transience’), accounting for 27% of variance, described how much individuals used feeders and was also repeatable (r: 0.34 to 0.62). While exhibiting consistent individual differences, birds also showed flexibility in foraging patterns, binge-eating less and using feeders more when they experienced greater local competition.Individuals in behaviourally dominant states (great tits, males and adults) binged more than subordinate birds (blue tits, females and juveniles) when their territories were distant from feeding stations. Moreover, great tits and males used feeders more than blue tits and females respectively, while birds feeding further from their territory used feeders less than those feeding closer. ‘Exploration behaviour’ was unrelated to both measures of daily foraging behaviour.This study presents some of the first evidence that birds use consistent alternative foraging tactics at a fine temporal scale. Individuals are consistent in their tactics, but also adjust their foraging behaviour with changes in local competition. Hence, studies of foraging behaviour should consider the extent to which such individual-level variability in foraging behaviour is under selection.This article is protected by copyright. All rights reserved.
      PubDate: 2017-02-13T02:00:27.973548-05:
      DOI: 10.1111/1365-2656.12651
       
  • Complex Inter-Kingdom interactions: Carnivorous plants affect growth of an
           aquatic vertebrate
    • Authors: Jon M. Davenport; Alex W. Riley
      Abstract: 1.Coexistence of organisms in nature is more likely when phenotypic similarities of individuals are reduced. Despite the lack of similarity, distantly related taxa still compete intensely for shared resources. No larger difference between organisms that share a common prey could exist than between carnivorous plants and animals. However, few studies have considered inter-Kingdom competition among carnivorous plants and animals.2.In order to evaluate interactions between a carnivorous plant (greater bladderwort, Utricularia vulgaris) and a vertebrate (bluegill, Lepomis macrochirus) on a shared prey (zooplankton), we conducted a mesocosm experiment. We deployed two levels of bladderwort presence (functional and crushed) and measured bluegill responses (survival and growth).3.Zooplankton abundance was reduced the greatest in bluegill and functional bladderworts treatments. Bluegill survival did not differ among treatments, but growth was greatest with crushed bladderwort. Thus bluegill growth was facilitated by reducing interference competition in the presence of crushed bladderwort. The facilitating effect was dampened, however, when functional bladderwort removed a shared prey.4.To our knowledge, this is one of the first studies to experimentally demonstrate interactions between a carnivorous plant and a fish. Our data suggests that carnivorous plants may actively promote or reduce animal co-occurrence from some ecosystems via facilitation or competition.This article is protected by copyright. All rights reserved.
      PubDate: 2017-02-13T02:00:22.43103-05:0
      DOI: 10.1111/1365-2656.12652
       
  • Functional and phylogenetic structure of island bird communities
    • Authors: Xingfeng Si; Marc W. Cadotte, Di Zeng, Andrés Baselga, Yuhao Zhao, Jiaqi Li, Yiru Wu, Siyu Wang, Ping Ding
      Abstract: 1. Biodiversity change in anthropogenically transformed habitats is often nonrandom, yet the nature and importance of the different mechanisms shaping community structure are unclear. Here, we extend the classic Theory of Island Biogeography (TIB) to account for nonrandom processes by incorporating species traits and phylogenetic relationships into a study of faunal relaxation following habitat loss and fragmentation.2. Two possible mechanisms can create nonrandom community patterns on fragment islands. First, small and isolated islands might consist of similar or closely related species because they are environmentally homogeneous or select for certain shared traits, such as dispersal ability. Alternatively, communities on small islands might contain more dissimilar or distantly related species than on large islands because limited space and resource availability result in greater competitive exclusion among species with high niche overlap.3. Breeding birds were surveyed on 36 islands and two mainland sites annually from 2010 to 2014 in the Thousand Island Lake region, China. We assessed community structure of breeding birds on these subtropical land-bridge islands by integrating species’ trait and evolutionary distances. We additionally analysed habitat heterogeneity and variance in size ratios to distinguish biotic and abiotic processes of community assembly.4. Results showed that functional-phylogenetic diversity increased with island area, and decreased with island isolation. Bird communities on the mainland were more diverse and generally less clustered than island bird communities and not different than randomly assembled communities. Bird communities on islands tend to be functionally similar and phylogenetically clustered, especially on small and isolated islands.5. The nonrandom decline in species diversity and change in bird community structure with island area and isolation, along with the relatively homogeneous habitats on small islands, support the environmental filtering hypothesis. Our study demonstrates the importance of integrating multiple forms of diversity for understanding the effects of habitat loss and fragmentation, and further reveals that TIB could be extended to community measures by moving beyond assumptions of species equivalency in colonisation rates and extinction susceptibilities.This article is protected by copyright. All rights reserved.
      PubDate: 2017-02-13T01:55:26.66437-05:0
      DOI: 10.1111/1365-2656.12650
       
  • Social and environmental factors affect tuberculosis related mortality in
           wild meerkats
    • Authors: Stuart Patterson; Julian A. Drewe, Dirk. U. Pfeiffer, Tim H. Clutton-Brock
      Abstract: 1.Tuberculosis (TB) is an important and widespread disease of wildlife, livestock, and humans worldwide, but long-term empirical datasets describing this condition are rare. A population of meerkats (Suricata suricatta) in South Africa's Kalahari Desert have been diagnosed with Mycobacterium suricattae, a novel strain of TB, causing fatal disease in this group-living species.2.This study aimed to find characteristics associated with clinical TB in meerkats. These characteristics could subsequently be used to identify “at risk” animals within a population, and target these individuals for control measures.3.We conducted a retrospective study based on a unique, long-term life history dataset of over 2000 individually-identified animals covering a 14-year period after the first confirmatory diagnosis of TB in this population in 2001. Individual- and group-level risk factors were analysed using time-dependent Cox regression to examine their potential influence on the time to development of end-stage TB.4.Cases of disease involved 144 individuals in 27 of 73 social groups, across 12 out of 14 years (an incidence rate of 3.78 cases/100 study years). At the individual level, increasing age had the greatest effect on risk of disease with a hazard ratio of 4.70 (95% CI: 1.92-11.53, p
      PubDate: 2017-02-10T07:10:28.79297-05:0
      DOI: 10.1111/1365-2656.12649
       
  • Habitat connectivity and local conditions shape taxonomic and functional
           diversity of arthropods on green roofs
    • Authors: S Braaker; M K Obrist, J Ghazoul, M Moretti
      Abstract: 1.Increasing development of urban environments creates high pressure on green spaces with potential negative impacts on biodiversity and ecosystem services. There is growing evidence that green roofs – rooftops covered with vegetation – can contribute mitigate the loss of urban green spaces by providing new habitats for numerous arthropod species.2.Whether green roofs can contribute to enhance taxonomic and functional diversity and increase connectivity across urbanized areas remains, however, largely unknown. Furthermore, only limited information is available on how environmental conditions shape green roof arthropod communities.3.We investigated the community composition of arthropods (Apidae, Curculionidae, Araneae and Carabidae) on 40 green roofs and 40 green sites at ground level in the city of Zurich, Switzerland. We assessed how the site's environmental variables (such as area, height, vegetation, substrate and connectivity among sites) affect species richness and functional diversity using generalized linear models. We used an extension of co-inertia analysis (RLQ) and fourth-corner analysis to highlight the mechanism underlying community assemblages across taxonomic groups on green roof and ground communities.4.Species richness was higher at ground-level sites, while no difference in functional diversity was found between green roofs and ground sites. Green roof arthropod diversity increased with higher connectivity and plant species richness, irrespective of substrate depth, height and area of green roofs. The species trait analysis reviewed the mechanisms related to the environmental predictors that shape the species assemblages of the different taxa at ground and roof sites.5.Our study shows the important contribution of green roofs in maintaining high functional diversity of arthropod communities across different taxonomic groups, despite their lower species richness compared to ground sites. Species communities on green roofs revealed to be characterized by specific trait assemblages. The study also provides details on the environmental conditions that influence arthropod diversity and gives new perspectives on how the design of green roofs can be improved to increase their ecological value. Furthermore, the study highlights the importance of integrating green roofs in planning policies which aim to enhance urban habitat connectivity.This article is protected by copyright. All rights reserved.
      PubDate: 2017-02-06T03:20:59.541301-05:
      DOI: 10.1111/1365-2656.12648
       
  • Organismal responses to habitat change: herbivore performance, climate,
           and leaf traits in regenerating tropical dry forests
    • Authors: Salvatore J. Agosta; Catherine M. Hulshof, Ethan G. Staats
      Abstract: 1.The ecological effects of large-scale climate change have received much attention, but the effects of the more acute form of climate change that results from local habitat alteration have been less explored. When forest is fragmented, cut, thinned, cleared or otherwise altered in structure, local climates and microclimates change. Such changes can affect herbivores both directly (e.g., through changes in body temperature) and indirectly (e.g., through changes in host plant traits).2.We advance an eco-physiological framework to understand the effects of changing forests on herbivorous insects. We hypothesize that if tropical forest caterpillars are climate and resource specialists, then they should have reduced performance outside of mature forest conditions.3.We tested this hypothesis with a field experiment contrasting the performance of Rothschildia lebeau (Saturniidae) caterpillars feeding on the host plant Casearia nitida (Salicaceae) in two different aged and structured tropical dry forests in Area de Conservación Guanacaste, Costa Rica.4.Compared to more mature closed-canopy forest, in younger secondary forest we found that: (1) ambient conditions were hotter, drier, and more variable; (2) caterpillar growth and development were reduced; and (3) leaves were tougher, thicker, and drier. Further, caterpillar growth and survival were negatively correlated with these leaf traits, suggesting indirect host-mediated effects of climate on herbivores.5.Based on the available evidence, and relative to mature forest, we conclude that reduced herbivore performance in young secondary forest could have been driven by changes in climate, leaf traits (which were likely climate induced), or both. However, additional studies will be needed to provide more direct evidence of cause-and-effect and to disentangle the relative influence of these factors on herbivore performance in this system.This article is protected by copyright. All rights reserved.
      PubDate: 2017-02-01T09:05:40.146632-05:
      DOI: 10.1111/1365-2656.12647
       
  • Dynamic vs. static social networks in models of parasite transmission:
           predicting Cryptosporidium spread in wild lemurs
    • Authors: Andrea Springer; Peter M. Kappeler, Charles L. Nunn
      Abstract: Social networks provide an established tool to implement heterogeneous contact structures in epidemiological models. Dynamic temporal changes in contact structure and ranging behaviour of wildlife may impact disease dynamics. A consensus has yet to emerge, however, concerning the conditions in which network dynamics impact model outcomes, as compared to static approximations that average contact rates over longer time periods. Furthermore, as many pathogens can be transmitted both environmentally and via close contact, it is important to investigate the relative influence of both transmission routes in real-world populations.Here, we use empirically derived networks from a population of wild primates, Verreaux's sifakas (Propithecus verreauxi), and simulated networks to investigate pathogen spread in dynamic vs. static social networks.First, we constructed a susceptible-exposed-infected-recovered model of Cryptosporidium spread in wild Verreaux's sifakas. We incorporated social and environmental transmission routes and parameterized the model for two different climatic seasons. Second, we used simulated networks and greater variation in epidemiological parameters to investigate the conditions in which dynamic networks produce larger outbreak sizes than static networks.We found that average outbreak size of Cryptosporidium infections in sifakas was larger when the disease was introduced in the dry season than in the wet season, driven by an increase in home range overlap towards the end of the dry season. Regardless of season, dynamic networks always produced larger average outbreak sizes than static networks. Larger outbreaks in dynamic models based on simulated networks occurred especially when the probability of transmission and recovery were low. Variation in tie strength in the dynamic networks also had a major impact on outbreak size, while network modularity had a weaker influence than epidemiological parameters that determine transmission and recovery.Our study adds to emerging evidence that dynamic networks can change predictions of disease dynamics, especially if the disease shows low transmissibility and a long infectious period, and when environmental conditions lead to enhanced between-group contact after an infectious agent has been introduced.Social networks are widely used in epidemiological models, but some methodological aspects of network-based modelling remain unclear. Here, empirical networks derived from a wild lemur population and simulated networks were used to investigate how the use of static vs. dynamic networks, seasonality, transmission modality and community structure affect pathogen spread.
      PubDate: 2017-01-31T08:51:38.028911-05:
      DOI: 10.1111/1365-2656.12617
       
  • Size structuring and allometric scaling relationships in coral reef fishes
    • Authors: Jillian C. Dunic; Julia K. Baum
      Abstract: Temperate marine fish communities are often size structured, with predators consuming increasingly larger prey and feeding at higher trophic levels as they grow. Gape limitation and ontogenetic diet shifts are key mechanisms by which size structuring arises in these communities. Little is known, however, about size structuring in coral reef fishes.Here, we aimed to advance understanding of size structuring in coral reef food webs by examining the evidence for these mechanisms in two groups of reef predators. Given the diversity of feeding modes amongst coral reef fishes, we also compared gape size—body size allometric relationships across functional groups to determine if they are reliable indicators of size structuring.We used gut content analysis and quantile regressions of predator size—prey size relationships to test for evidence of gape limitation and ontogenetic niche shifts in reef piscivores (n=13 species) and benthic invertivores (n=3 species). We then estimated gape size—body size allometric scaling coefficients for 21 different species from four functional groups, including herbivores/detritivores, which are not expected to be gape-limited.We found evidence of both mechanisms for size structuring in coral reef piscivores, with maximum prey size scaling positively with predator body size, and ontogenetic diet shifts including prey type and expansion of prey size. There was, however, little evidence of size structuring in benthic invertivores. Across species and functional groups, absolute and relative gape sizes were largest in piscivores as expected, but gape size—body size scaling relationships were not indicative of size structuring. Instead, relative gape sizes and mouth morphologies may be better indicators.Our results provide evidence that coral reef piscivores are size-structured, and that gape limitation and ontogenetic niche shifts are the mechanisms from which this structure arises. Although gape allometry was not indicative of size structuring, it may have implications for ecosystem function: positively allometric gape size—body size scaling relationships in herbivores/detritivores suggests that loss of large-bodied individuals of these species will have a disproportionately negative impact on reef grazing pressure.This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-18T14:50:22.832989-05:
      DOI: 10.1111/1365-2656.12637
       
  • Intrapopulation variability in the timing of ontogenetic habitat shifts in
           sea turtles revealed using δ15N values from bone growth rings
    • Authors: Calandra N. Turner Tomaszewicz; Jeffrey A. Seminoff, S. Hoyt Peckham, Larisa Avens, Carolyn M. Kurle
      Abstract: Determining location and timing of ontogenetic shifts in the habitat use of highly migratory species, along with possible intrapopulation variation in these shifts, is essential for understanding mechanisms driving alternate life histories and assessing overall population trends. Measuring variations in multi-year habitat-use patterns is especially difficult for remote oceanic species.To investigate the potential for differential habitat use among migratory marine vertebrates, we measured the naturally occurring stable nitrogen isotope (δ15N) patterns that differentiate distinct ocean regions to create a ‘regional isotope characterization’, analysed the δ15N values from annual bone growth layer rings from dead-stranded animals, and then combined the bone and regional isotope data to track individual animal movement patterns over multiple years.We used humeri from juvenile North Pacific loggerhead turtles (Caretta caretta), animals that undergo long migrations across the North Pacific Ocean (NPO), using multiple discrete regions as they develop to adulthood. Typical of many migratory marine species, ontogenetic changes in habitat use throughout their decades-long juvenile stage is poorly understood, but each potential habitat has unique foraging opportunities and spatially explicit natural and anthropogenic threats that could affect key life-history parameters.We found a bimodal size/age distribution in the timing that juveniles underwent an ontogenetic habitat shift from the oceanic central North Pacific (CNP) to the neritic east Pacific region near the Baja California Peninsula (BCP) (42·7 ± 7·2 vs. 68·3 ± 3·4 cm carapace length, 7·5 ± 2·7 vs. 15·6 ± 1·7 years). Important to the survival of this population, these disparate habitats differ considerably in their food availability, energy requirements and threats, and these differences can influence life-history parameters such as growth, survival and future fecundity. This is the first evidence of alternative ontogenetic shifts and habitat-use patterns for juveniles foraging in the eastern NPO.We combine two techniques, skeletochronology and stable isotope analysis, to reconstruct multi-year habitat-use patterns of a remote migratory species, linked to estimated ages and body sizes of individuals, to reveal variable ontogeny during the juvenile life stage that could drive alternate life histories and that has the potential to illuminate the migration patterns for other species with accretionary tissues.This article combines skeletochronology with stable isotope analysis of annual bone growth layers to assess the variability in the size/age at which endangered juvenile North Pacific loggerhead sea turtles undergo an ontogenetic habitat shift between two disparate developmental foraging habitats, one of which is a sink habitat.
      PubDate: 2017-01-11T06:25:27.666435-05:
      DOI: 10.1111/1365-2656.12618
       
  • Professor Dr. Dr. h.c. mult. Manfred Kirchgessner
    • Authors: K. Eder
      Pages: 401 - 401
      PubDate: 2017-03-13T06:57:26.563698-05:
      DOI: 10.1111/jpn.12717
       
  • The dynamics of transmission and the dynamics of networks
    • Authors: Damien Farine
      Pages: 415 - 418
      Abstract: A toy example depicted here highlighting the results of a study in this issue of the Journal of Animal Ecology that investigates the impact of network dynamics on potential disease outbreaks. Infections (stars) that spread by contact only (left) reduce the predicted outbreak size compared to situations where individuals can become infected by moving through areas that previously contained infected individuals (right). This is potentially important in species where individuals, or in this case groups, have overlapping ranges (as depicted on the top right). Incorporating network dynamics that maintain information about the ordering of contacts (central blocks; including the ordering of spatial overlap as noted by the arrows that highlight the blue group arriving after the red group in top-right of the figure) is important for capturing how a disease might not have the opportunity to spread to all individuals. By contrast, a static or ‘average’ network (lower blocks) does not capture any of these dynamics. Interestingly, although static networks generally predict larger outbreak sizes, the authors find that in cases when transmission probability is low, this prediction can switch as a result of changes in the estimated intensity of contacts among individuals. [Colour figure can be viewed at wileyonlinelibrary.com].Springer, A., Kappeler, P.M. & Nunn, C.L. (2017) Dynamic vs. static social networks in models of parasite transmission: Predicting Cryptosporidium spread in wild lemurs. Journal of Animal Ecology, 86, 419–433.The spread of disease or information through networks can be affected by several factors. Whether and how these factors are accounted for can fundamentally change the predicted impact of a spreading epidemic. Springer, Kappeler & Nunn () investigate the role of different modes of transmission and network dynamics on the predicted size of a disease outbreak across several groups of Verreaux's sifakas, a group-living species of lemur. While some factors, such as seasonality, led to consistent differences in the structure of social networks, using dynamic vs. static representations of networks generated differences in the predicted outbreak size of an emergent disease. These findings highlight some of the challenges associated with studying disease dynamics in animal populations, and the importance of continuing efforts to develop the network tools needed to study disease spread.Social network structure can fundamentally shape transmission dynamics. However, networks can capture different modes of interactions and can vary in structure at different temporal scales. Taking such factors into account can change predictions about outbreak size and population susceptibility, and should be carefully considered in studies of animal social networks.
      PubDate: 2017-04-10T03:59:30.79379-05:0
      DOI: 10.1111/1365-2656.12659
       
  • Genetic Allee effects and their interaction with ecological Allee effects
    • Authors: Meike J. Wittmann; Hanna Stuis, Dirk Metzler
      Abstract: It is now widely accepted that genetic processes such as inbreeding depression and loss of genetic variation can increase the extinction risk of small populations. However, it is generally unclear whether extinction risk from genetic causes gradually increases with decreasing population size or whether there is a sharp transition around a specific threshold population size. In the ecological literature, such threshold phenomena are called ‘strong Allee effects’ and they can arise for example from mate limitation in small populations.In this study, we aim to (i) develop a meaningful notion of a ‘strong genetic Allee effect’, (ii) explore whether and under what conditions such an effect can arise from inbreeding depression due to recessive deleterious mutations, and (iii) quantify the interaction of potential genetic Allee effects with the well-known mate-finding Allee effect.We define a strong genetic Allee effect as a genetic process that causes a population's survival probability to be a sigmoid function of its initial size. The inflection point of this function defines the critical population size. To characterize survival-probability curves, we develop and analyse simple stochastic models for the ecology and genetics of small populations.Our results indicate that inbreeding depression can indeed cause a strong genetic Allee effect, but only if individuals carry sufficiently many deleterious mutations (lethal equivalents). Populations suffering from a genetic Allee effect often first grow, then decline as inbreeding depression sets in and then potentially recover as deleterious mutations are purged. Critical population sizes of ecological and genetic Allee effects appear to be often additive, but even superadditive interactions are possible.Many published estimates for the number of lethal equivalents in birds and mammals fall in the parameter range where strong genetic Allee effects are expected. Unfortunately, extinction risk due to genetic Allee effects can easily be underestimated as populations with genetic problems often grow initially, but then crash later. Also interactions between ecological and genetic Allee effects can be strong and should not be neglected when assessing the viability of endangered or introduced populations.The modeling results indicate that inbreeding depression can produce a strong Allee effect where populations below a certain critical size tend to go extinct. Such genetic Allee effects can interact with ecological Allee effects, for example those due to mate-finding difficulties, to increase the extinction risk of small populations.
      PubDate: 2016-11-10T07:00:37.633849-05:
      DOI: 10.1111/1365-2656.12598
       
  • Effects of dietary supplementing tannic acid in the ration of beef cattle
           on rumen fermentation, methane emission, microbial flora and nutrient
           digestibility
    • Authors: K. Yang; C. Wei, G. Y. Zhao, Z. W. Xu, S. X. Lin
      Pages: 302 - 310
      Abstract: Four adult Simmental male cattle (376 ± 9.0 kg initial BW), fitted with permanent rumen cannulas, were used in a 4 × 4 Latin square design to investigate the effects of dietary supplementing tannic acid (TA) on rumen fermentation, methane (CH4) production, rumen microbes, nutrient digestibility and plasma biochemical parameters. Four levels of TA, that is 0, 6.5, 13.0 or 26.0 g/kg dry matter (DM), were added to the basal ration (composed of corn silage and concentrate mixture) as experimental treatments respectively. Each experimental period consisted of a 12-day adaptation phase followed by a 3-day sampling phase. The results showed that supplementing TA at 26.0 g/kg DM decreased the relative abundance of protozoa, methanogens and Ruminococcus albus to the total ruminal bacterial 16S rDNA in beef cattle (p 
      PubDate: 2016-06-08T01:33:31.437608-05:
      DOI: 10.1111/jpn.12531
       
  • Effect of a probiotic Lactobacillus plantarum TN8 strain on
           trinitrobenzene sulphonic acid-induced colitis in rats
    • Authors: I. Trabelsi; N. Ktari, S. Ben Slima, K. Hamden, R. Ben Salah
      Pages: 311 - 319
      Abstract: This study aimed to investigate the potential effects of an oral treatment by a newly isolated probiotic Lactobacillus plantarum TN8 strain on trinitrobenzene sulphonic acid (TNBS)-induced colitis in Wistar rats. Thus, 18 rats were divided into three groups (n = 6 per group): group 1 (control) – rats not receiving TNBS application; group 2 – rats receiving an intrarectal TNBS infusion (100 mg/kg TNBS dissolved in ethanol); and group 3 – rats treated with intragastrical TN8 strain once per day (for 5 days before TNBS induction). The performance and the effects of the probiotic treatment were evaluated using a series of histological, biophysical and biochemical analyses. The results have shown that the treatment with the L. plantarum TN8 strain improves the body weight and reduces the diarrhoea, colonic mucosal inflammation and colon shortening. TN8-treated rats showed a significant decrease in the total cholesterol content from 1.86 (for group 2) to 1.32 mmol/l and in triglyceride (TG) content from 2.09 (for group 2) to 1.23 mmol/l. Furthermore, the findings revealed that the high-density lipoprotein (HDL) cholesterol contents increased from 0.95 to 1.02 mmol/l. The histological studies have confirmed that the architecture of the liver and kidney tissues of the TN8-treated rats were found to be improved. Overall, the results suggest that the L. plantarum TN8 presents promising perspectives for the development of safe and cost-effective agents for the prevention or alleviation of several intestinal pathologies.
      PubDate: 2016-07-20T05:25:35.135931-05:
      DOI: 10.1111/jpn.12536
       
  • Impact of macronutrient composition and palatability in wet diets on food
           selection in cats
    • Authors: F. Salaun; G. Blanchard, L. Le Paih, F. Roberti, C. Niceron
      Pages: 320 - 328
      Abstract: Cats are obligate carnivores adapted to high-protein diets, but are commonly fed diets rich in carbohydrate. The aim of this study was to examine the food intake choices of cats when diets with different protein and carbohydrate contents were offered. Thirty-nine cats participated in voluntary dietary intake studies. Four foods were formulated to provide between 24% and 53% of metabolizable energy as protein, between 43% and 11% as carbohydrate and holding dietary fat constant with a contribution of approximately 36%. Foods were offered either singly to evaluate voluntary food intake or in pairs to compare food intake between pairs of diets. Cats regulated their macronutrient intake to attain an overall diet composition that provided 53% of metabolizable energy as protein, 11% as carbohydrate and 36% as fat. The protein contribution corresponded to approximately 6 g of protein/kg body weight/day. High-protein/low-carbohydrate diets were always eaten preferentially over low-protein/high-carbohydrate foods. When low-protein/high-carbohydrate diets were offered, cats limited their food intake to limit daily carbohydrate intake to less than 3 g of carbohydrate/kg body weight. This carbohydrate ceiling may limit protein and even energy intake when only low-protein/high-carbohydrate diets were offered. The inclusion of palatability enhancer in the diets increased food intake but did not change protein or carbohydrate intake patterns, indicating that macronutrient intake can be regulated regardless of the use of palatability enhancers in cats. We conclude that cats can discriminate between diets based on macronutrient composition and regulate their intake to maintain maximal protein intake but limit carbohydrate intake.
      PubDate: 2016-06-09T00:50:45.269395-05:
      DOI: 10.1111/jpn.12542
       
  • Pre-soaking of the feed pellets: a trick for successful feed utilization
           in juvenile green turtles (Chelonia mydas Linnaeus, 1758)
    • Authors: H. Kanghae; K. Thongprajukaew, W. Phromkunthong, S. Plangsri, S. Jatupornpitukchat, K. Kittiwattanawong
      Pages: 329 - 338
      Abstract: Pre-soaking of the feed pellets in water can improve feed utilization in juvenile green turtles (Chelonia mydas Linnaeus, 1758), but the pre-soaking has not previously been optimized. This study aimed to optimize the water amount used for pre-soaking the pellets. The experiments followed a completely randomized design with three replications of each dietary treatment group. Initially 10-day-old green turtles (20–22 g body weight) were treated in an indoor aquaculture system for 3 months. The dietary treatment pellets were pre-soaked with 0.3, 0.5 or 0.7 (v/w) relative amounts of water that are here termed soaking ratios. At the end of experiment, there were no significant differences in survival (96% on average) and growth (average body weight 75.34 g and specific growth rate 2%/day, on average) of turtles in three dietary treatments (p > 0.05). Feed utilization was the best in turtles fed with 0.7 pre-soaked ratio, as indicated by significant reductions (p 
      PubDate: 2016-01-20T22:59:34.370188-05:
      DOI: 10.1111/jpn.12444
       
  • Determination of the energy value of corn distillers dried grains with
           solubles containing different oil levels when fed to growing pigs
    • Authors: Z.-C. Li; P. Li, D.-W. Liu, D.-F. Li, F.-L. Wang, Y.-B. Su, Z.-P. Zhu, X.-S. Piao
      Pages: 339 - 348
      Abstract: This experiment used indirect calorimetry to determine the net energy (NE) content of five corn distillers dried grains with solubles (corn DDGS) containing different oil levels and to compare the NE obtained using indirect calorimetry with that calculated using previously published prediction equations. There were two samples of high-oil DDGS, one sample of medium-oil DDGS and two samples of low-oil DDGS. Twelve barrows (initial BW of 32.8 ± 2.0 kg) were used in a repeated 3 × 6 Youden square design with three periods and six diets. The diets were comprised of a corn–soybean meal basal diet and five diets containing 29.25% of one of the corn DDGS added at the expense of corn and soybean meal. During each period, the pigs were individually housed in metabolism crates for 16 days which included 7 days for adaption to feed and environmental conditions. On day 8, the pigs were transferred to respiration chambers and fed one of the six diets at 2300 kJ ME/kg BW0.6/day. Faeces and urine were collected from day 9 to 13 and heat production (HP) was also measured. From day 14 to 15, the pigs were fed 893 kJ ME/kg BW0.6/day to allow them to adapt from the fed to the fasted state. On the last day of each period (day 16), the pigs were fasted and fasting HP was measured. The digestible energy value was 16.0, 17.1 and 15.3 MJ/kg DM, the metabolizable energy value was 14.6, 15.5 and 13.7 MJ/kg DM and the NE value was 10.7, 11.0 and 9.4 MJ/kg DM, for the high-oil, medium-oil and low-oil corn DDGS, respectively. The NE obtained with indirect calorimetry in the present study did not differ from values calculated using previously published prediction equations.
      PubDate: 2016-02-09T04:25:35.147972-05:
      DOI: 10.1111/jpn.12445
       
  • Effects of beta-glucans ingestion (Saccharomyces cerevisiae) on metabolism
           of rats receiving high-fat diet
    • Authors: T. V. Araújo; E. F. Andrade, R. V. Lobato, D. R. Orlando, N. F. Gomes, R. V. Sousa, M. G. Zangeronimo, L. J. Pereira
      Pages: 349 - 358
      Abstract: We investigated the effects of beta-glucans (Saccharomyces cerevisiae) ingestion on metabolic parameters of Wistar rats receiving high-fat diet. The experimental period was divided into two stages: in the first one, the animals were divided into two groups containing 12 animals each. The first group received commercial feed and the second received high-fat diet containing 20% of pork fat during 60 days. At the end of this period, body weight, blood glucose and Lee index were assessed. In the second stage, those 24 animals were redivided into four groups: (C) – control diet; (CB) – control diet and treated with Beta-glucan (BG); (O) – obese animals and (OB) – obese animals treated with BG. Animals from groups CB and OB received 30 mg/kg of BG dissolved in saline solution by gavage. Animals from groups C and O received only saline solution for 28 days. The design used was totally randomized in 2 × 2 factorial scheme. Data were submitted to analysis of variance (anova). Animals from OB group showed inferior levels (p 
      PubDate: 2016-03-14T07:46:23.915068-05:
      DOI: 10.1111/jpn.12452
       
  • Effect of maternal canthaxanthin and 25-hydroxycholecalciferol
           supplementation on the performance of ducklings under two different
           vitamin regimens
    • Authors: Z. Z. Ren; S. Z. Jiang, Q. F. Zeng, X. M. Ding, S. P. Bai, J. P. Wang, Y. H. Luo, Z. W. Su, Y. Xuan, K. Y. Zhang
      Pages: 359 - 368
      Abstract: This study investigated the effects of maternal canthaxanthin (CX, 6 mg/kg) and 25-hydroxycholecalciferol (25-OH-D3, 0.069 mg/kg) supplementation on the performance of Cherry Valley ducklings under two different vitamin regimens. A total of 780 duck breeder females and 156 males were randomly allotted to two diets with or without the addition of the mixture of CX and 25-OH-D3 (CX+25-OH-D3) for 32 weeks. Ducklings (males and females separately) hatched from eggs laid at 24 weeks of the duck breeder trial were fed with a NRC vitamin regimen, and ducklings (males and females separately) hatched from eggs laid at 32 weeks of the duck breeder trial were fed with a HIGH vitamin regimen (had higher levels of all vitamins except biotin than NRC vitamin regimen), for 14 days. The results showed that, maternal CX+25-OH-D3 supplementation increased the shank pigmentation for 7-days post hatch in ducklings under a NRC vitamin regimen, and for 14-days post hatch in ducklings under a HIGH vitamin regimen. Growth performance, antioxidant status and serum phosphorus of ducklings under a NRC vitamin regimen were increased by maternal CX+25-OH-D3 supplementation; however, these positive effects were not observed in ducklings under a HIGH vitamin regimen. Males revealed increased growth performance in ducklings under both NRC and HIGH vitamin regimens. Sexual differences in shank pigmentation, antioxidant status, tibia strength and serum phosphorus were not consistent as they were dependent on maternal CX+25-OH-D3 status or dietary vitamin regimens. Data suggest that maternal CX+25-OH-D3 supplementation is important for starter ducklings under a NRC vitamin regimen, but not HIGH vitamin regimen.
      PubDate: 2016-04-14T22:46:45.083773-05:
      DOI: 10.1111/jpn.12453
       
  • Transport of fatty acids within plasma lipoproteins in lactating and
           non-lactating cows fed on fish oil and hydrogenated palm oil
    • Authors: E. Vargas-Bello-Pérez; G. Íñiguez-González, P. C. Garnsworthy, J. J. Loor
      Pages: 369 - 377
      Abstract: The aim of this study was to elucidate the effect of dietary fish oil (FO) and a blend of FO and hydrogenated palm oil (FOPO) on transport of fatty acids (FA) within plasma lipoproteins in lactating and non-lactating cows. Two trials were conducted (one with lactating and another with non-lactating dairy cows) in two 3 × 3 Latin squares that included three periods of 21 days. Dietary treatments for lactating cows consisted of a basal diet (Control; no fat supplement), and fat-supplemented diets containing FO (500 g/day/cow) and FOPO (250 FO + 250 g/day/cow hydrogenated palm oil). For non-lactating cows, dietary treatments consisted of a basal diet (Control; no fat supplement), and fat-supplemented diets containing FO (170 g/day/cow) and FOPO (85 FO + 85 hydrogenated palm oil g/day/cow). In lactating cows, compared with control and FOPO, FO increased C16:0, C18:3 cis-9, 12, 15, C18:2 cis-9, trans-11 and total saturated and polyunsaturated FA in plasma and increased C16:0, C18:2 cis-9, trans-11, total polyunsaturated and total polyunsaturated n-6 in high-density lipoprotein (HDL), whereas in non-lactating cows, compared with control and FOPO, FO increased C16:0, C18:1 trans-11, C18:2 trans-9, 12, C18:2 cis-9, trans-11, C20:5 n-3 and total saturated and polyunsaturated FA in plasma; C16:0, C18:1 trans-11, C18:1 cis-9, C18:2 trans-9, 12, C20:5 n-3 and total monounsaturated FA in HDL; and C18:1 trans-6-8, C18:1 trans-9, C18:1 trans-10, C18:1 trans-11, C18:3 cis-9, 12, 15 and C20:5 n-3 in low-density lipoprotein (LDL). FO increased C20:5 n-3 in plasma and lipoproteins in non-lactating cows and increased C18:3 cis-9, 12, 15 in plasma (in lactating cows) and LDL (in non-lactating cows). We concluded from results of this study that in bovine plasma, the LDL fraction appears to be the main lipoprotein transporting C18:1 trans isomers and is more responsive than other lipoprotein fractions to variation in supply of dietary lipids.
      PubDate: 2016-06-09T00:50:34.275718-05:
      DOI: 10.1111/jpn.12545
       
  • Live performance, carcass characteristic and blood metabolite responses of
           broilers to two distinct corn types with different extent of grinding
    • Authors: J. P. Zhao; D. P. Cui, Z. Y. Zhang, H. C. Jiao, Z. G. Song, H. Lin
      Pages: 378 - 388
      Abstract: The major objective of this research was to establish the main and interactive effects of corn type and extent of grinding on broiler performance including carcass characteristics. A completely randomized experimental design with a 2 (corn type) × 2 (fine and coarse) factorial arrangement, each with six replicates of 45 male Ross chicks, was applied. Experimental diets, containing dent or hard corn, were formulated with two extents of grinding (3.00 or 6.00 mm screens) for three growing phases. In comparison with dent corn, the hard corn increased body weight (BW) gain and thigh muscle yield (p 
      PubDate: 2016-04-14T22:47:08.161059-05:
      DOI: 10.1111/jpn.12451
       
  • P and Ca requirements for Japanese quail
    • Authors: C. B. L. Mariz; J. H. V. Silva, J. J. Filho, M. R. Lima, F. G. P. Costa
      Pages: 389 - 400
      Abstract: Four experiments were conducted to estimate the phosphorus and calcium requirements for weight maintenance and weight gain in Japanese quails during their growth phase from 16 to 36 days. Japanese quails aged 16 days were used for estimating the phosphorous and calcium requirements for weight maintenance or weight gain, with these quails composing each reference slaughter group and the others distributed in a completely randomized design, housed in cages of galvanized wire (33 × 33 × 16 cm) that were stored in acclimatized chambers with specific environmental temperatures. The light programme used during the 20-day experimental period was 24 h of artificial light. Analysis of the data showed that the prediction equations for estimating the phosphorus and calcium requirements for weight maintenance and weight gain of Japanese quails between 16 and 36 days of age were P (g/quail/day) = P0.75*(9.3695 + 7.7397*T) + 9.70*WG, in which P is the phosphorus requirement, and Ca (g/quail/day) = P0.75*(363.99 – 8.0262*T) + 28.15*WG, in which Ca is the calcium requirement, P is BW (kg), T is temperature (°C) and WG (g/quail/day).
      PubDate: 2016-03-17T23:51:46.366436-05:
      DOI: 10.1111/jpn.12446
       
 
 
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