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  Subjects -> BIOLOGY (Total: 2912 journals)
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    - ZOOLOGY (142 journals)

ZOOLOGY (142 journals)                  1 2     

Acta Herpetologica     Open Access   (Followers: 3)
Acta Theriologica     Full-text available via subscription   (Followers: 6)
Acta Zoologica     Hybrid Journal   (Followers: 3)
Acta Zoologica Cracoviensia     Free   (Followers: 2)
Acta zoológica mexicana     Open Access  
Advances in Zoology     Open Access  
Advances in Zoology and Botany     Open Access  
African Invertebrates     Open Access  
African Journal of Herpetology     Full-text available via subscription   (Followers: 1)
African Journal of Wildlife Research     Full-text available via subscription  
African Zoology     Hybrid Journal   (Followers: 7)
American Journal of Zoological Research     Open Access  
animal     Hybrid Journal   (Followers: 4)
Animal Behaviour     Hybrid Journal   (Followers: 131)
Animal Biology     Hybrid Journal   (Followers: 8)
Animal Biology & Animal Husbandry     Open Access   (Followers: 4)
Animal Biotelemetry     Open Access   (Followers: 2)
Animal Genetics     Hybrid Journal   (Followers: 7)
Animal Migration     Open Access   (Followers: 2)
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  
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: 8)
Applied Animal Behaviour Science     Hybrid Journal   (Followers: 18)
Applied Entomology and Zoology     Partially Free   (Followers: 2)
Aquatic Mammals     Full-text available via subscription   (Followers: 8)
Aquatic Sciences     Hybrid Journal   (Followers: 13)
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   (Followers: 1)
Bangladesh Journal of Zoology     Open Access  
Bioacoustics : The International Journal of Animal Sound and its Recording     Partially Free   (Followers: 3)
Bird Conservation International     Hybrid Journal   (Followers: 20)
Bird Study     Full-text available via subscription   (Followers: 24)
Brazilian Journal of Veterinary Research and Animal Science     Open Access   (Followers: 7)
British Birds     Full-text available via subscription   (Followers: 21)
Bulletin of the Museum of Comparative Zoology     Full-text available via subscription   (Followers: 4)
Canadian Journal of Animal Science     Full-text available via subscription   (Followers: 4)
Canadian Journal of Zoology     Full-text available via subscription   (Followers: 17)
Contributions to Zoology     Open Access   (Followers: 3)
Der Zoologische Garten     Full-text available via subscription   (Followers: 3)
Ecology of Freshwater Fish     Hybrid Journal   (Followers: 18)
Edentata     Open Access  
European Journal of Taxonomy     Open Access   (Followers: 3)
Euscorpius     Open Access  
EvoDevo     Open Access   (Followers: 1)
Fieldiana Zoology     Full-text available via subscription   (Followers: 1)
Fish and Fisheries     Hybrid Journal   (Followers: 25)
Frontiers in Zoology     Open Access   (Followers: 8)
Graellsia     Open Access  
Herpetology Notes     Open Access  
Hystrix, the Italian Journal of Mammalogy     Open Access  
i-Perception     Open Access   (Followers: 3)
Iheringia. Série Zoologia     Open Access  
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: 2)
International Journal of Zoology     Open Access   (Followers: 2)
International Studies on Sparrows     Open Access  
International Zoo Yearbook     Hybrid Journal   (Followers: 2)
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: 53)
Journal of Animal Physiology and Animal Nutrition     Hybrid Journal   (Followers: 5)
Journal of Apicultural Science     Open Access   (Followers: 1)
Journal of Applied Animal Research     Hybrid Journal   (Followers: 1)
Journal of Basic & Applied Zoology : Physiology     Open Access   (Followers: 2)
Journal of Experimental Zoology Part A: Ecological Genetics and Physiology     Hybrid Journal   (Followers: 3)
Journal of Experimental Zoology Part B : Molecular and Developmental Evolution     Hybrid Journal   (Followers: 1)
Journal of Freshwater Ecology     Hybrid Journal   (Followers: 12)
Journal of Herpetology     Full-text available via subscription   (Followers: 6)
Journal of Insects     Open Access  
Journal of Venomous Animals and Toxins     Open Access   (Followers: 4)
Journal of Venomous Animals and Toxins including Tropical Diseases     Open Access  
Journal of Wildlife Management     Hybrid Journal   (Followers: 35)
Journal of Zoo and Aquarium Research     Open Access   (Followers: 1)
Journal of Zoological Systematics and Evolutionary Research     Hybrid Journal   (Followers: 3)
Journal of Zoology     Hybrid Journal   (Followers: 20)
Laboratory Animals     Hybrid Journal   (Followers: 12)
Mammalia     Hybrid Journal   (Followers: 7)
Marine Ecology Progress Series MEPS     Hybrid Journal   (Followers: 20)
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  
Neotropical Primates     Open Access   (Followers: 1)
New Zealand Journal of Zoology     Hybrid Journal   (Followers: 2)
Papéis Avulsos de Zoologia     Open Access  
Parasite     Open Access   (Followers: 6)
Physiological and Biochemical Zoology     Full-text available via subscription   (Followers: 5)
Polish Journal of Entomology     Open Access   (Followers: 4)
Primate Biology     Open Access  
Protist Genomics     Open Access   (Followers: 1)

        1 2     

Journal Cover Journal of Animal Ecology
  [SJR: 3.074]   [H-I: 102]   [53 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  [1598 journals]
  • Selective extinction drives taxonomic and functional alpha and beta
           diversities in island bird assemblages
    • Abstract: 1.Taxonomic diversity considers all species being equally different from each other, and thus disregards species’ different ecological functions. Exploring taxonomic and functional aspects of biodiversity simultaneously can better understand the processes of community assembly. 2.We analyzed taxonomic and functional alpha and beta diversities of breeding bird assemblages on land‐bridge islands in the Thousand Island Lake, China. Given the high dispersal ability of most birds at this spatial scale (several kilometers), we predicted (i) selective extinction driving alpha and beta diversities after the creation of land‐bridge islands of varying area, and (ii) low taxonomic and functional beta diversities that were not correlated to spatial distance. 3.Breeding birds were surveyed on 37 islands annually from 2007 to 2014. We decomposed beta diversity of breeding birds into spatial turnover and nestedness‐resultant components, and related taxonomic and functional diversities to island area and isolation using power regression models (for alpha diversity) and multiple regression models on distance matrices (for beta diversity). We then ran simulations to assess the strength of the correlations between taxonomic and functional diversities. 4.Results revealed that both taxonomic and functional alpha diversities increased with island area. The taxonomic nestedness‐resultant and turnover components increased and decreased with difference in area, respectively, but functional counterparts did not. Isolation played a minor role in explaining alpha‐ and beta‐diversity patterns. By partitioning beta diversity, we found low levels of overall taxonomic and functional beta diversities. The functional nestedness‐resultant component dominated overall functional beta diversity, whereas taxonomic turnover was the dominant component for taxonomic beta diversity. The simulation showed that functional alpha and beta diversities were significantly correlated with taxonomic diversities, and the observed values of correlations were significantly different from null expectations of random extinction. 5.Our assessment of island bird assemblages validated the predictions of no distance effects and low beta diversity due to pervasive dispersal events among islands, and also suggested that selective extinction drives taxonomic and functional alpha and beta diversities. The contrasting turnover and nestedness‐resultant components of taxonomic and functional beta diversities demonstrate the importance of considering the multifaceted nature of biodiversity when examining community assembly. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-08T06:10:16.357075-05:
      DOI: 10.1111/1365-2656.12478
       
  • Integrated population modelling reveals a perceived source to be a cryptic
           sink
    • Authors: Mitch D. Weegman; Stuart Bearhop, Anthony D. Fox, Geoff M. Hilton, Alyn J. Walsh, Jennifer L. McDonald, David J. Hodgson
      Abstract: 1.Demographic links among fragmented populations are commonly studied as source‐sink dynamics, whereby source populations exhibit net recruitment and net emigration, while sinks suffer net mortality but enjoy net immigration. It is commonly assumed that large, persistent aggregations of individuals must be sources, but this ignores the possibility that they are sinks instead, buoyed demographically by immigration. 2.We tested this assumption using Bayesian integrated population modelling of Greenland white‐fronted geese (Anser albifrons flavirostris) at their largest wintering site (Wexford, Ireland), combining capture‐mark‐recapture, census and recruitment data collected from 1982 to 2010. Management for this subspecies occurs largely on wintering areas; thus, study of source‐sink dynamics of discrete regular wintering units provides unprecedented insights into population regulation and enables identification of likely processes influencing population dynamics at Wexford and among 70 other Greenland white‐fronted goose wintering subpopulations. 3.Using results from integrated population modelling, we parameterized an age‐structured population projection matrix to determine the contribution of movement rates (emigration and immigration), recruitment and mortality to the dynamics of the Wexford subpopulation. 4.Survival estimates for juvenile and adult birds at Wexford, and adult birds elsewhere fluctuated over the 29‐year study period, but were not identifiably different. However, per capita recruitment rates at Wexford in later years (post‐1995) were identifiably lower than in earlier years (pre‐1995). The observed persistence of the Wexford subpopulation was only possible with high rates of immigration, which exceeded emigration in each year. Thus, despite its apparent stability, Wexford has functioned as a sink over the entire study period. 5.These results demonstrate that even large subpopulations can potentially be sinks, and that movement dynamics (e.g. immigration) among winters can dramatically obscure key processes driving subpopulation size. Further, novel population models which integrate capture‐mark‐recapture, census and recruitment data are essential to correctly ascribing source‐sink status and accurately informing development of site‐safeguard networks. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-08T06:09:45.567266-05:
      DOI: 10.1111/1365-2656.12481
       
  • Linking structure and function in food webs: maximization of different
           ecological functions generates distinct food‐web structures
    • Abstract: 1.Trophic interactions are central to ecosystem functioning, but the link between food‐web structure and ecosystem functioning remains obscure. Regularities (i.e., consistent patterns) in food‐web structure suggest the possibility of regularities in ecosystem functioning, which might be used to relate structure to function. 2.We introduce a novel, genetic‐algorithm approach to simulate food webs with maximized throughput (a proxy for ecosystem functioning), and compare the structure of these simulated food webs to real empirical food webs using common metrics of food‐web structure. We repeat this analysis using robustness to secondary extinctions (a proxy for ecosystem resilience) instead of throughput to determine the relative contributions of ecosystem functioning and ecosystem resilience to food‐web structure. 3.Simulated food webs that maximized robustness were similar to real food webs when connectance (i.e., levels of interaction across the food web) was high, but this result did not extend to food webs with low connectance. Simulated food webs that maximized throughput or a combination of throughput and robustness were not similar to any real food webs. 4.Simulated maximum‐throughput food webs differed markedly from maximum‐robustness food webs, which suggests that maximizing different ecological functions can generate distinct food‐web structures. Based on our results, food‐web structure would appear to have a stronger relationship with ecosystem resilience than with ecosystem throughput. 5.Our genetic‐algorithm approach is general and is well suited to large, realistically complex food webs. Genetic algorithms can incorporate constraints on structure and can generate outputs that can be compared directly to empirical data. Our method can be used to explore a range of maximization or minimization hypotheses, providing new perspectives on the links between structure and function in ecological systems. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-08T06:09:25.250742-05:
      DOI: 10.1111/1365-2656.12484
       
  • Experimental evidence for within‐ and cross‐seasonal effects
           of fear on survival and reproduction
    • Authors: Kyle H. Elliott; Gustavo S. Betini, Ian Dworkin, D. Ryan Norris
      Abstract: Fear of predation can have non‐lethal effects on individuals within a season but whether, and to what extent, these effects carry‐over into subsequent seasons is not known. Using a replicated seasonal population of the common fruit fly, Drosophila melanogaster, we examined both within‐ and cross‐seasonal effects of fear on survival and reproductive output. Compared to controls, flies exposed to the scent of mantid (Tenodera sinensis) predators in the non‐breeding season had 64% higher mortality, and lost 60% more mass by the end of the non‐breeding season and, in the subsequent breeding season, produced 20% fewer offspring that weighed 9% less at maturity. Flies exposed to the scent of mantids in the breeding season did not produce fewer offspring, but their offspring developed faster and weighed less as adults compared to the controls. Our results demonstrate how effects of fear can be manifested both within and across seasons and emphasize the importance of understanding how events throughout the annual cycle influence individual success of animals living in seasonal environments. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-08T06:07:25.676323-05:
      DOI: 10.1111/1365-2656.12487
       
  • Endemicity of chytridiomycosis features pathogen over‐dispersion
    • Authors: Laura F. Grogan; Andrea. D. Phillott, Benjamin C. Scheele, Lee Berger, Scott D. Cashins, Sara C. Bell, Robert Puschendorf, Lee F. Skerratt
      Abstract: 1.Pathogens can be critical drivers of the abundance and distribution of wild animal populations. The presence of an over‐dispersed pathogen load distribution between hosts (where few hosts harbor heavy parasite burdens and light infections are common) can have an important stabilizing effect on host‐pathogen dynamics where infection intensity determines pathogenicity. This may potentially lead to endemicity of an introduced pathogen rather than extirpation of the host and/or pathogen. 2.Over‐dispersed pathogen load distributions have rarely been considered in wild animal populations as an important component of the infection dynamics of microparasites such as bacteria, viruses, protozoa and fungi. 3.Here we examined the abundance, distribution and transmission of the model fungal pathogen Batrachochytrium dendrobatidis (Bd, cause of amphibian chytridiomycosis) between wild‐caught Litoria rheocola (common mist frogs) to investigate the effects of an over‐dispersed pathogen load distribution on the host population in the wild. We quantified host survival, infection incidence and recovery probabilities relative to infectious burden, and compared the results of models where pathogen over‐dispersion either was or was not considered an important feature of host‐pathogen dynamics. 4.We found the distribution of Bd load between hosts to be highly over‐dispersed. We found that host survival was related to infection burden, and that accounting for pathogen over‐dispersion allowed us to better understand infection dynamics and their implications for disease control. In addition, we found that the pattern of host infections and recoveries varied markedly with season whereby (i) infections established more in winter, consistent with temperature dependent effects on fungal growth, and (ii) recoveries (loss of infection) occurred frequently in the field throughout the year but were less likely in winter. 5.Our results suggest that pathogen over‐dispersion is an important feature of endemic chytridiomycosis, and that intensity of infection determines disease impact. These findings have important implications for our understanding of chytridiomycosis dynamics and the application of management strategies for disease mitigation. We recommend quantifying individual infectious burdens rather than infection state where possible in microparasitic diseases. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-04T21:14:08.663191-05:
      DOI: 10.1111/1365-2656.12500
       
  • Integrating the pace‐of‐life syndrome across species, sexes
           and individuals: covariation of life history and personality under
           pesticide exposure
    • Abstract: 1.The pace‐of‐life syndrome (POLS) hypothesis integrates covariation of life‐history traits along a fast‐slow continuum and covariation of behavioural traits along a proactive‐reactive personality continuum. Few studies have investigated these predicted life‐history/personality associations among species and between sexes. Furthermore, whether and how contaminants interfere with POLS patterns remains unexplored. 2.We tested for covariation patterns in life history and in behaviour, and for life‐history/personality covariation among species, among individuals within species and between sexes. Moreover, we investigated whether pesticide exposure affects covariation between life history and behaviour and whether species and sexes with a faster POLS strategy have a higher sensitivity to pesticides. 3.We reared larvae of four species of Ischnura damselflies in a common garden experiment with an insecticide treatment (chlorpyrifos absent/present) in the final instar. We measured four life‐history traits (larval growth rate during the pesticide treatment and development time; adult mass and lifespan) and two behavioural traits (larval feeding activity and boldness, each before and after the pesticide treatment). 4.At the individual level, life‐history traits and behavioural traits aligned along a fast‐slow and a proactive‐reactive continuum, respectively. Species‐specific differences in life history, with fast‐lived species having a faster larval growth and development, a lower mass at emergence and a shorter lifespan, suggested that time constraints in the larval stage were predictably driving life‐history evolution both in the larval stage and across metamorphosis in the adult stage. Across species, females were consistently more slow‐lived than males, reflecting that a large body size and a long lifespan are generally more important for females. In contrast to the POLS hypothesis, there was only little evidence for the expected positive coupling between life‐history pace and proactivity. Pesticide exposure decreased larval growth rate and affected life‐history/personality covariation in the most fast‐lived species. 5.Our study supports the existence of life‐history and behavioural continua with limited support for life‐history/personality covariation. Variation in digestive physiology may explain this decoupling of life history and behaviour and provide valuable mechanistic insights to understand and predict the occurrence of life‐history/personality covariation patterns. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-04T12:51:17.123915-05:
      DOI: 10.1111/1365-2656.12499
       
  • Incorporating animal spatial memory in step selection functions
    • Abstract: Memory is among the most important and neglected forces that shapes animal movement patterns. Research on the movement‐memory interface is crucial to understand how animals use spatial learning to navigate across space because memory‐biased navigation is directly linked to animals’ space use and home range behaviour; however, because memory cannot be measured directly, it is difficult to account for. Here, we incorporated spatial memory into Step Selection Functions (SSF) to understand how resource selection and spatial memory affect space use of feral hogs (Sus scrofa). We used Biased Random Bridge kernel estimates linked to residence time as a surrogate for memory and tested four conceptually different dynamic maps of spatial memory. We applied this memory‐based SSF to a data set of hog relocations to evaluate the importance of land cover type, time of day, and spatial memory on the animals’ space use. Our approach has shown how the incorporation of spatial memory into animal movement models can improve estimates of habitat selection. Memory‐based SSF provided a feasible way to gain insight into how animals use spatial learning to guide their movement decisions. We found that while hogs selected forested areas and water bodies and avoided grasslands during the day (primarily at noon), they had a strong tendency to select previously visited areas, mainly those held in recent memory. Beyond actively updating their memory with recent experiences, hogs were able to discriminate among spatial memories encoded at different circadian phases of their activity. Even though hogs are thought to have long memory retention, they likely relied on recent experiences because the local food resources are quickly depleted and slowly renewed, yielding an uncertain spatial distribution of resources. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-04T05:53:49.376971-05:
      DOI: 10.1111/1365-2656.12485
       
  • Inter‐annual variation and long‐term trends in proportions of
           resident individuals in partially migratory birds
    • Abstract: 1.Partial migration – a part of a population migrates and another part stays resident year‐round on the breeding site – is probably the most common type of migration in the animal kingdom, yet it has only lately garnered more attention. Theoretical studies indicate that in partially migratory populations the proportion of resident individuals (PoR) should increase in high latitudes in response to the warming climate, but empirical evidence exists for few species. 2.We provide the first comprehensive overview of the environmental factors affecting PoR and the long‐term trends in PoR by studying 27 common partially migratory bird species in Finland. 3.The annual PoR values were calculated by dividing the winter bird abundances by the preceding breeding abundances. First, we analysed whether early‐winter temperature, winter temperature year before or the abundance of tree seeds just before overwintering, explain the inter‐annual variation in PoR. Second, we analysed the trends in PoR between 1987 and 2011. 4.Early‐winter temperature explained the inter‐annual variation in PoR in the waterbirds (waterfowl and gulls), most likely because the temperature affects the ice conditions and thereby the feeding opportunities for the waterbirds. In terrestrial species, the abundance of seeds was the best explanatory variable. Previous winter's temperature did not explain PoR in any species, thus we conclude that variation in food availability caused the inter‐annual variation in PoR. During the study period PoR increased in waterbirds but did not change in terrestrial birds. 5.Partially migratory species living in physically contrasting habitats can differ in their annual and long‐term population‐level behavioural responses to warming climate, possibly because warm winter temperatures reduce ice cover and improve the feeding possibilities of waterbirds but do not directly regulate the food availability for terrestrial birds. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-04T05:53:06.917766-05:
      DOI: 10.1111/1365-2656.12486
       
  • The rules for symbiont community assembly change along a
           mutualism‐parasitism continuum
    • Authors: James Skelton; Sam Doak, Meredith Leonard, Robert P. Creed, Bryan L. Brown
      Abstract: 1.Symbiont community assembly is driven by host‐symbiont and symbiont‐symbiont interactions.The effects that symbionts exert on their hosts are often context‐dependent and existing theoretical frameworks of symbiont community assembly do not consider the implications of variable outcomes to assembly processes. 2.We hypothesized that symbiont‐symbiont interactions become increasingly important along a parasitism/mutualism continuum because; a) negative outcomes favor host resistance which in turn reduces symbiont colonization and subsequently reduce symbiont‐symbiont interactions, whereas b) positive host outcomes favor tolerance and consequently higher symbiont colonization rates, leading to stronger interactions among symbionts. We found support for this hypothesis in the cleaning symbiosis between crayfish and ectosymbiotic branchiobdellidan worms. 3.The symbiosis between crayfish and their worms can shift from parasitism/commensalism to mutualism as crayfish age. Here, field surveys identified changes in worm density, diversity, and composition that were concomitant to changing symbiosis outcomes. We conducted several laboratory experiments and behavioral assays to relate patterns from the field to their likely causal processes. 4.Young crayfish typically hosted only two relatively small worm species. Older crayfish hosted two additional larger species. In laboratory experiments, young crayfish exhibited a directed grooming response to all worm species, but were unable to remove small species. Conversely, adult crayfish did not exhibit grooming responses to any worm species. Relaxed grooming allowed the colonization of large worm species and initiated symbiont‐symbiont intraguild predation that reduced the abundance and altered the behavior of small worm species. Thus, the dominant processes of symbiont community assembly shifted from host resistance to symbiont‐symbiont interactions through host ontogeny and a concomitant transition towards mutualism. 5.This work shows that host resistance can have a prevailing influence over symbiont community assembly when symbiosis is disadvantageous to the host. However, when symbiosis is advantageous and resistance is relaxed, symbiont colonization rate and consequently abundance and diversity increases, and interactions among symbionts become increasingly important to symbiont community assembly. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-01T01:51:42.019059-05:
      DOI: 10.1111/1365-2656.12498
       
  • Migratory connectivity and effects of winter temperatures on migratory
           behaviour of the European robin Erithacus rubecula: a continent‐wide
           analysis
    • Abstract: 1.Many partially migratory species show phenotypically divergent populations in terms of migratory behaviour, with climate hypothesized to be a major driver of such variability through its differential effects on sedentary and migratory individuals. 2.Based on long‐term (1947‐2011) bird ringing data, we analysed phenotypic differentiation of migratory behaviour among populations of the European robin Erithacus rubecula across Europe. 3.We showed that clusters of populations sharing breeding and wintering ranges varied from partial (British Isles and Western Europe, NW cluster) to completely migratory (Scandinavia and North‐Eastern Europe, NE cluster). 4.Distance migrated by birds of the NE (but not of the NW) cluster decreased through time because of a north‐eastwards shift in the wintering grounds. Moreover, when winter temperatures in the breeding areas were cold, individuals from the NE cluster also migrated longer distances, while those of the NW cluster moved over shorter distances. 5.Climatic conditions may therefore affect migratory behaviour of robins, although large geographical variation in response to climate seems to exist. This article is protected by copyright. All rights reserved.
      PubDate: 2016-01-28T10:02:50.77945-05:0
      DOI: 10.1111/1365-2656.12497
       
  • COMADRE: a global data base of animal demography
    • Abstract: The open‐data scientific philosophy is being widely adopted and proving to promote considerable progress in ecology and evolution. Open‐data global data bases now exist on animal migration, species distribution, conservation status, etc. However, a gap exists for data on population dynamics spanning the rich diversity of the animal kingdom world‐wide. This information is fundamental to our understanding of the conditions that have shaped variation in animal life histories and their relationships with the environment, as well as the determinants of invasion and extinction. Matrix population models (MPMs) are among the most widely used demographic tools by animal ecologists. MPMs project population dynamics based on the reproduction, survival and development of individuals in a population over their life cycle. The outputs from MPMs have direct biological interpretations, facilitating comparisons among animal species as different as Caenorhabditis elegans, Loxodonta africana and Homo sapiens. Thousands of animal demographic records exist in the form of MPMs, but they are dispersed throughout the literature, rendering comparative analyses difficult. Here, we introduce the COMADRE Animal Matrix Database, an open‐data online repository, which in its version 1.0.0 contains data on 345 species world‐wide, from 402 studies with a total of 1625 population projection matrices. COMADRE also contains ancillary information (e.g. ecoregion, taxonomy, biogeography, etc.) that facilitates interpretation of the numerous demographic metrics that can be derived from its MPMs. We provide R code to some of these examples. Synthesis: We introduce the COMADRE Animal Matrix Database, a resource for animal demography. Its open‐data nature, together with its ancillary information, will facilitate comparative analysis, as will the growing availability of databases focusing on other aspects of the rich animal diversity, and tools to query and combine them. Through future frequent updates of COMADRE, and its integration with other online resources, we encourage animal ecologists to tackle global ecological and evolutionary questions with unprecedented sample size. Population ecologists have developed and published thousands of matrix population models for animals ranging from C. elegans to corals, sheep, lions or even humans, but these data were dispersed in the literature. The authors introduce the COMADRE Animal Matrix Database, an open‐data repository with high‐resolution demographic information for animals world‐wide .
      PubDate: 2016-01-27T00:27:54.776002-05:
      DOI: 10.1111/1365-2656.12482
       
  • Age‐dependent and age‐independent sexual selection on multiple
           male traits in the lekking black grouse (Lyrurus tetrix)
    • Authors: Matti Kervinen; Christophe Lebigre, Carl D. Soulsbury
      Abstract: 1.Individuals’ reproductive success is often strongly associated with their age, with typical patterns of early life reproductive improvement and late life senescence. These age‐related patterns are due to the inherent trade‐offs between life history traits competing for a limited amount of resources available to the organisms. In males, such trade‐offs are exacerbated by the resource requirements associated with the expression of costly sexual traits, leading to dynamic changes in trait expression throughout their lifespan. 2.Due to the age‐dependency of male phenotypes, the relationship between the expression of male traits and mating success can also vary with male age. Hence, using longitudinal data in a lekking species with strong sexual selection – the black grouse Lyrurus tetrix – we quantified the effects of age, lifespan and age of first lek attendance (AFL) on male annual mating success (AMS) to separate the effects of within‐individual improvement and senescence on AMS from selective (dis)appearance of certain phenotypes. Then, we used male AMS to quantify univariate and multivariate sexual selection gradients on male morphological and behavioural traits with and without accounting for age and age‐related effects of other traits. 3.Male AMS increased with age and there was no significant reproductive senescence. Most males never copulated and of the ones that did, the majority had only one successful year. Lifespan was unrelated to AMS, but early AFL tended to lead to higher AMS at ages 1 to 3. AMS was related to morphological and behavioural traits when male age was ignored. Accounting for age and age‐specific trait effects (i.e. the interaction between a trait and age) reduced the magnitude of the selection gradients and revealed that behavioural traits are under consistent sexual selection, while sexual selection on morphological traits is stronger in old males. 4.Therefore, sexual selection in black grouse operates primarily on male behaviour and morphological traits may act as additional cues to supplement female choice. These results demonstrate the multifaceted influence of age on both fitness and sexual traits and highlight the importance of accounting for such effects when quantifying sexual selection. This article is protected by copyright. All rights reserved.
      PubDate: 2016-01-22T02:46:46.498887-05:
      DOI: 10.1111/1365-2656.12496
       
  • Do animals exercise to keep fit'
    • Authors: Lewis G. Halsey
      Abstract: We humans know we are not physically fit unless we do extra, voluntary exercise. Yet we have never asked whether the same is true for animals. If it is, then give that energy will be spent keeping fit this raises important issues about new energetic trade‐offs, which have never been considered.
      PubDate: 2016-01-21T02:00:03.242992-05:
      DOI: 10.1111/1365-2656.12488
       
  • Behavioral Flexibility in Migratory Behavior in a Long‐Lived Large
           Herbivore
    • Authors: Scott L. Eggeman; Mark Hebblewhite, Holger Bohm, Jesse Whittington, Evelyn H. Merrill
      Abstract: 1.Migratory animals are predicted to enhance lifetime fitness by obtaining higher quality forage and/or reducing predation risk compared to non‐migratory conspecifics. Despite evidence for behavioral flexibility in other taxa, previous research on large mammals has often assumed that migratory behavior is a fixed behavioral trait. 2.Migratory behavior may be plastic for many species, although few studies have tested for individual‐level flexibility using long‐term monitoring of marked individuals, especially in large mammals such as ungulates. 3.We tested variability in individual migratory behavior using a ten‐year telemetry dataset of 223 adult female elk (Cervus elaphus) in the partially migratory Ya Ha Tinda population in Alberta, Canada. 4.We used net squared displacement (NSD) to classify migratory strategy for each individual elk year. Individuals switched between migrant and resident strategies at a mean rate of 15% per year, and migrants were more likely to switch than residents. We then tested how extrinsic (climate, elk/wolf abundance) and intrinsic (age) factors affected the probability of migrating, and, second, the decision to switch between migratory strategies. 5. Over 630 individual elk‐years, the probability of an individual elk migrating increased following a severe winter, in years of higher wolf abundance, and with increasing age. 6.At an individual elk level, we observed 148 switching events out of 430 possible transitions in elk monitored at least 2 years. We found switching was density‐dependent, where migrants switched to a resident strategy at low elk abundance, but residents switched more to a migrant strategy at high elk abundance. Precipitation during the previous summer had a weak carryover effect, with migrants switching slightly more following wetter summers, whereas residents showed the opposite pattern. Older migrant elk rarely switched, whereas resident elk switched more frequently to migrate at older ages. 7.Our results show migratory behavior in ungulates is an individually variable trait that can respond to intrinsic, environmental, and density‐dependent forces. Different strategies had opposing responses to density‐dependent and intrinsic drivers, providing a stabilizing mechanism for the maintenance of partial migration and demographic fitness in this population. This article is protected by copyright. All rights reserved.
      PubDate: 2016-01-20T10:05:49.391011-05:
      DOI: 10.1111/1365-2656.12495
       
  • Do sunbirds use taste to decide how much to drink'
    • Authors: Ida E. Bailey; Susan W. Nicolson
      Abstract: Nectarivorous birds typically consume smaller meals of more concentrated than of less concentrated sugar solutions. It is not clear, however, whether they use taste to decide how much to consume or if they base this decision on post‐ingestive feedback. Taste, a cue to nectar concentration, is available to nectarivores during ingestion whereas post‐ingestive information about resource quality becomes available only after a meal. When conditions are variable, we would expect nectarivorous birds to base their decisions on how much to consume on taste, as post‐ingestive feedback from previous meals would not be a reliable cue to current resource quality. Here we tested whether white‐bellied sunbirds (Cinnyris talatala), foraging from an array of artificial flowers, use taste to decide how much to consume per meal when nectar concentration is highly variable: they did not. Instead, how much they chose to consume per meal appeared to depend on the energy intake at the previous meal, i.e. how hungry they were. Our birds did, however, appear to use taste to decide how much to consume per flower visited within a meal. Unexpectedly, some individuals preferred to consume more from flowers with lower concentration rewards and some preferred to do the opposite. We draw attention to the fact that many studies perhaps misleadingly claim that birds use sweet taste to inform their foraging decisions, as they analyse mean data for multiple meals over which post‐ingestive feed back will have become available rather than data for individual meals when only sensory information is available. We discuss how conflicting foraging rules could explain why sunbirds do not use sweet taste to inform their meal size decisions. This article is protected by copyright. All rights reserved.
      PubDate: 2016-01-20T09:15:52.365272-05:
      DOI: 10.1111/1365-2656.12479
       
  • Intraguild predation leads to cascading effects on habitat choice,
           behaviour and reproductive performance
    • Abstract: 1.Intraguild predation (IGP) is a commonly recognised mechanism influencing the community structure of predators, but the complex interactions are notoriously difficult to disentangle. The mesopredator suppression hypothesis predicts that a superpredator may either simultaneously repress two mesopredators, restrain the dominant one and thereby release the subdominant mesopredator, or elicit different responses by both mesopredators. 2.We show the outcome arising from such conditions in a three‐level predator assemblage (Eurasian eagle owl Bubo bubo L., northern goshawk Accipiter gentilis L., and common buzzard Buteo buteo L.) studied over 25 years. In the second half of the study period, the eagle owl re‐colonised the study area, thereby providing a natural experiment of superpredator introduction. We combined this setup with detailed GIS‐analysis of habitat use and a field experiment simulating intrusion by the superpredator into territories of the subdominant mesopredator, the buzzard. 3.Although population trends were positive for all three species in the assemblage, the proportion of failed breeding attempts increased significantly in both mesopredators after the superpredator re‐colonised the area. 4.We predicted that superpredator‐induced niche shifts in the dominant mesopredator may facilitate mesopredator coexistence in superpredator‐free refugia. We found significant changes in nesting habitat choice in goshawk, but not in buzzard. Since competition for enemy‐free refugia and the rapid increase in population density may have constrained niche shifts of the subdominant mesopredator, we further predicted behavioural changes in response to the superpredator. The field experiment indeed showed a significant increase in aggressive response of buzzards toward eagle owl territory intrusion over the course of ten years, probably due to phenotypic plasticity in the response towards superpredation risk. 5.Overall, our results show that intraguild predation can be a powerful force of behavioural change, simultaneously influencing habitat use and aggressiveness in predator communities. These changes might help to buffer mesopredator populations against the negative effects of intraguild predation. This article is protected by copyright. All rights reserved.
      PubDate: 2016-01-19T08:11:25.328585-05:
      DOI: 10.1111/1365-2656.12493
       
  • The response of migratory populations to phenological change: a Migratory
           Flow Network modelling approach
    • Authors: Caz M. Taylor; Andrew J. Laughlin, Richard J. Hall
      Abstract: 1.Declines in migratory species have been linked to anthropogenic climate change through phenological mismatch, which arises due to asynchronies between the timing of life‐history events (such as migration) and the phenology of available resources. Long‐distance migratory species may be particularly vulnerable to phenological change in their breeding ranges, since the timing of migration departure is based on environmental cues at distant non‐breeding sites. 2.Migrants may, however, be able to adjust migration speed en route to the breeding grounds and thus ability of migrants to update their timing of migration may depend critically on stopover frequency during migration; however, understanding how migratory strategy influences population dynamics is hindered by a lack of predictive models explicitly linking habitat quality to demography and movement patterns throughout the migratory cycle. 3.Here, we present a novel modelling framework, the Migratory Flow Network (MFN), in which the seasonally varying attractiveness of breeding, winter, and stopover regions drives the direction and timing of migration based on a simple general flux law. 4.We use the MFN to investigate how populations respond to shifts in breeding site phenology based on their frequency of stopover and ability to detect and adapt to these changes. 5.With perfect knowledge of advancing phenology, ‘jump’ migrants (low frequency stopover) require more adaptation for populations to recover than ‘hop’ and ‘skip’ (high or medium frequency stopover) migrants. If adaptation depends on proximity, hop and skip migrants’ populations can recover but jump migrants cannot adjust and decline severely. 6.These results highlight the importance of understanding migratory strategies and maintaining high‐quality stopover habitat to buffer migratory populations from climate‐induced mismatch. 7.We discuss how MFNs could be applied to diverse migratory taxa, and highlight the potential of MFNs as a tool for exploring how migrants respond to other environmental changes such as habitat loss. This article is protected by copyright. All rights reserved.
      PubDate: 2016-01-19T08:08:49.079154-05:
      DOI: 10.1111/1365-2656.12494
       
  • Fitness consequences of early life conditions and maternal size effects in
           a freshwater top predator
    • Abstract: 1.Conditions experienced in early life stages can be an important determinant of individual life histories. In fish, environmental conditions are known to affect early survival and growth, but recent studies have also emphasized maternal effects mediated by size or age. However, the relative sensitivity of the mean fitness (population growth rate λ) to different early life impacts remain largely unexplored. 2.Using a female‐based integral projection model (IPM) parameterised from unique long‐term demographic data for pike (Esox lucius), we evaluated the relative fitness consequences of different early life impacts, including i) maternal effects of length on egg weight, potentially affecting offspring (first year) survival, and ii) effects of temperature on offspring growth and survival. Of the seven vital rates defining the model, offspring survival could not be directly estimated and four scenarios were defined for this rate. 3.Elasticity analyses of the IPM were performed to calculate i) the total contribution from different lengths to the elasticity of λ to the projection kernel, and ii) the elasticity of λ to underlying variables of female current length, female offspring length at age 1, and temperature. These elasticities were decomposed into contributions from different vital rates across length. 4.Egg weight increased with female length, as expected, but the effect leveled off for the largest females. However, λ was largely insensitive to this effect, even when egg weight was assumed to have a strong effect on offspring survival. In contrast, λ was sensitive to early temperature conditions through growth and survival. Among mature females, the total elasticity of λ to the projection kernel generally increased with length. The results were robust to a wide range of assumptions. 5.These results suggest that environmental conditions experienced in early life represent a more important driver of mean population growth and fitness of pike than maternal effects of size on offspring survival.We discuss two general mechanisms underlying the weak influence of this maternal effect, suggesting that these may be general for long‐lived and highly fecund fishes. This model and results are relevant for management of long‐lived top‐predators, including many commercially important fish species. This article is protected by copyright. All rights reserved.
      PubDate: 2016-01-19T03:08:21.407067-05:
      DOI: 10.1111/1365-2656.12489
       
  • Impacts of warming revealed by linking resource growth rates with consumer
           functional responses
    • Authors: Derek C. West; David M. Post
      Abstract: Summary 1.Warming global temperatures are driving changes in species distributions, growth and timing, but much uncertainty remains regarding how climate change will alter species interactions. 2.Consumer‐Resource interactions in particular can be strongly impacted by changes to the relative performance of interacting species. While consumers generally gain an advantage over their resources with increasing temperatures, nonlinearities can change this relation near temperature extremes. 3.We use an experimental approach to determine how temperature changes between 5 and 30 °C will alter the growth of the algae Scenedesmus obliquus and the functional responses of the small bodied Daphnia ambigua and the larger D. pulicaria. 4.The impact of warming generally followed expectations, making both Daphnia species more effective grazers, with the increase in feeding rates outpacing the increases in algal growth rate. At the extremes of our temperature range, however, warming resulted in a decrease in Daphnia grazing effectiveness. Between 25 and 30°C both species of Daphnia experienced a precipitous drop in feeding rates, while algal growth rates remained high, increasing the likelihood of algal blooms in warming summer temperatures. 5.D. pulicaria performed significantly better at cold temperatures than D. ambigua, but by 20°C there was no significant difference between the two species and at 25°C D. ambigua out‐performed D. pulicaria. Warming summer temperatures will favor the smaller D. ambigua, but only over a narrow temperature range and warming beyond 25°C could open D. ambigua to invasion from tropical species. 6.By fitting our results to temperature dependent functions we develop a temperature and density dependent model which produces a metric of grazing effectiveness, quantifying the grazer density necessary to halt algal growth. This approach should prove useful for tracking the transient dynamics of other density dependent consumer‐resource interactions, such as agricultural pests and biological control agents. This article is protected by copyright. All rights reserved.
      PubDate: 2016-01-18T21:26:36.213931-05:
      DOI: 10.1111/1365-2656.12491
       
  • Stable coexistence of ecologically identical species: conspecific
           aggregation via reproductive interference
    • Authors: Lasse Ruokolainen; Ilkka Hanski
      Abstract: 1.Stable coexistence of ecologically identical species is not possible according to the established ecological theory. Many coexistence mechanisms have been proposed, but they all involve some form of ecological differentiation among the competing species. 2.The aggregation model of coexistence would predict coexistence of identical species if there would be a mechanism that generates spatially aggregated distributions that are not completely correlated among the species. Our aim is to demonstrate that continued dispersal, triggered by reproductive interference between ecologically identical species is such a mechanism. This study has been motivated by species using ephemeral patchy resources, such as decomposing fruits, fungal sporophores, carrion, and dung. 3.We analyse an individual‐based model with sexual reproduction, in which the progeny develops in ephemeral resource patches and the new generation disperses to a new set of patches. We assume spatially restricted dispersal, that patches differ in detectability, and that unmated females continue dispersal. 4.In the model, reproductive interference (males spend some time searching for and/or attempting to mate with heterospecific females) reduces the mating rate of females, especially in the less common species, which leads to increased dispersal and reduces spatial correlation in species’ distributions. 5.For a wide range of parameter values, coexisting species show a systematic difference in their relative abundances due to two opposing forces: uncommon species have reduced growth rate (Allee effect), which decreases abundance, but an abundance difference between the species reduces interspecific spatial correlation, which in turn reduces interspecific competition and allows the rarer species to persist at low density. 6.Our results demonstrate a new mechanism for coexistence that is not based on ecological differentiation between species. This article is protected by copyright. All rights reserved.
      PubDate: 2016-01-18T21:23:21.728038-05:
      DOI: 10.1111/1365-2656.12490
       
  • Continental‐scale travelling waves in forest geometrids in Europe:
           an evaluation of the evidence
    • Abstract: A recent paper claims the existence of one of the most large‐scale travelling waves ever recorded for any animal population. Here we address why conceptual and methodological pitfalls may have served to exaggerate or even impose the spatial patterns reported. Photo credit: Jane U. Jepsen
      PubDate: 2016-01-16T12:21:19.752692-05:
      DOI: 10.1111/1365-2656.12444
       
  • A response to Jepsen et al. 2015
    • Authors: Olle Tenow
      Abstract: Important findings, e.g. in ecology, should be questioned and debated. Our findings that defoliating looper outbreaks travel as waves across Europe and the response here to such a questioning could be a start of a debate (photo: winter moth carterpillar).
      PubDate: 2016-01-16T11:37:12.514451-05:
      DOI: 10.1111/1365-2656.12476
       
  • Warming can enhance invasion success through asymmetries in energetic
           performance
    • Authors: Marcin R. Penk; Jonathan M. Jeschke, Dan Minchin, Ian Donohue
      Abstract: 1.Both climate warming and biological invasions are prominent drivers of global environmental change and it is important to determine how they interact. However, beyond tolerance and reproductive thresholds, little is known about temperature‐dependence of invaders’ performance, particularly in light of competitive attributes of functionally similar native species. 2.We used experimentally derived energy budgets and field temperature data to determine whether anticipated warming will asymmetrically affect the energy budgets of the globally invasive Ponto‐Caspian mysid crustacean Hemimysis anomala and a functionally similar native competitor (Mysis salemaai) whose range is currently being invaded. 3.In contrast to M. salemaai, which maintains a constant feeding rate with temperature leading to diminishing energy assimilation, we found that H. anomala increases its feeding rate with temperature in parallel with growing metabolic demand. This enabled the invader to maintain high energy assimilation rates, conferring substantially higher scope for growth compared to the native analogue at spring‐to‐autumn temperatures. Anticipated warming will likely exacerbate this energetic asymmetry and remove the winter overlap, which, given the seasonal limitation of mutually preferred prey, appears to underpin coexistence of the two species. 4.These results indicate that temperature‐dependent asymmetries in scope for growth between invaders and native analogues comprise an important mechanism determining invasion success under warming climates. They also highlight the importance of considering relevant spectra of ecological contexts in predicting successful invaders and their impacts under warming scenarios. This article is protected by copyright. All rights reserved.
      PubDate: 2016-01-11T06:39:20.973744-05:
      DOI: 10.1111/1365-2656.12480
       
  • Response to Strona & Fattorini: are generalist parasites being lost
           from their hosts'
    • Authors: Maxwell J. Farrell; Patrick R. Stephens, T. Jonathan Davies
      Abstract: We respond to criticism of our recent paper by examining assumptions about the structure of host‐parasite networks, and discuss the implications of host extinction on our perception of parasite specificity.
      PubDate: 2016-01-11T06:38:34.48114-05:0
      DOI: 10.1111/1365-2656.12470
       
  • Are generalist parasites being lost from their hosts'
    • Authors: Giovanni Strona; Simone Fattorini
      Abstract: Co‐extinctions should be regarded as fundamental co‐evolutionary events promoting species turnover, prior than a consequence of human induced biodiversity loss. Focusing on current scenarios is key to biodiversity conservation, but predicting future trends could be harder and less fruitful than trying to get a better grasp on the past.
      PubDate: 2016-01-11T06:38:11.850337-05:
      DOI: 10.1111/1365-2656.12443
       
  • Opportunities and challenges of Integral Projection Models for modelling
           host–parasite dynamics
    • Abstract: Epidemiological dynamics are shaped by and may in turn shape host demography. These feedbacks can result in hard to predict patterns of disease incidence. Mathematical models that integrate infection and demography are consequently a key tool for informing expectations for disease burden and identifying effective measures for control. A major challenge is capturing the details of infection within individuals and quantifying their downstream impacts to understand population‐scale outcomes. For example, parasite loads and antibody titres may vary over the course of an infection and contribute to differences in transmission at the scale of the population. To date, to capture these subtleties, models have mostly relied on complex mechanistic frameworks, discrete categorization and/or agent‐based approaches. Integral Projection Models (IPMs) allow variance in individual trajectories of quantitative traits and their population‐level outcomes to be captured in ways that directly reflect statistical models of trait–fate relationships. Given increasing data availability, and advances in modelling, there is considerable potential for extending this framework to traits of relevance for infectious disease dynamics. Here, we provide an overview of host and parasite natural history contexts where IPMs could strengthen inference of population dynamics, with examples of host species ranging from mice to sheep to humans, and parasites ranging from viruses to worms. We discuss models of both parasite and host traits, provide two case studies and conclude by reviewing potential for both ecological and evolutionary research. Epidemiological dynamics are shaped by and may in turn shape host demography. Here, the authors extend statistically derived population models that explicitly account for variance in individual trajectories commonly used for plant and animal demography (Integral Projection Models) to capture the process of infection and propagate it across scales.
      PubDate: 2015-12-01T03:00:24.341813-05:
      DOI: 10.1111/1365-2656.12456
       
  • How well can body size represent effects of the environment on demographic
           rates' Disentangling correlated explanatory variables
    • Authors: Mollie E. Brooks; Marianne Mugabo, Gwendolen M. Rodgers, Timothy G. Benton, Arpat Ozgul
      Abstract: Demographic rates are shaped by the interaction of past and current environments that individuals in a population experience. Past environments shape individual states via selection and plasticity, and fitness‐related traits (e.g. individual size) are commonly used in demographic analyses to represent the effect of past environments on demographic rates. We quantified how well the size of individuals captures the effects of a population's past and current environments on demographic rates in a well‐studied experimental system of soil mites. We decomposed these interrelated sources of variation with a novel method of multiple regression that is useful for understanding nonlinear relationships between responses and multicollinear explanatory variables. We graphically present the results using area‐proportional Venn diagrams. Our novel method was developed by combining existing methods and expanding upon them. We showed that the strength of size as a proxy for the past environment varied widely among vital rates. For instance, in this organism with an income breeding life history, the environment had more effect on reproduction than individual size, but with substantial overlap indicating that size encompassed some of the effects of the past environment on fecundity. This demonstrates that the strength of size as a proxy for the past environment can vary widely among life‐history processes within a species, and this variation should be taken into consideration in trait‐based demographic or individual‐based approaches that focus on phenotypic traits as state variables. Furthermore, the strength of a proxy will depend on what state variable(s) and what demographic rate is being examined; that is, different measures of body size (e.g. length, volume, mass, fat stores) will be better or worse proxies for various life‐history processes. The strength of size as a proxy for past environments varies among vital rates. The authors quantified this using a novel method for understanding nonlinear relationships between responses and multicollinear predictors. This non‐mechanistic model has the strength of being flexible enough to apply in data‐limited situations and will be useful for identifying patterns and generating hypotheses.
      PubDate: 2015-12-01T02:59:58.443702-05:
      DOI: 10.1111/1365-2656.12465
       
  • Unravelling the role of allochthonous aquatic resources to food web
           structure in a tropical riparian forest
    • Abstract: 1.The role of matter and energy flow across ecosystem boundaries for subsidized consumer populations is well known. However, little is known on the effects of allochthonous subsidies on food web structure and trophic niche dimensions of consumers in the tropics. 2.We excluded allochthonous aquatic insects from tropical streams using greenhouse‐type exclosures to test the influence of aquatic allochthonous subsidies on the trophic structure and niche dimensions of terrestrial predators using stable isotope methods. 3.In exclosure treatments, abundance and biomass of terrestrial predators, and biomass of phytophages, decreased and increased, respectively. Vegetation‐living predators were more responsive to allochthonous inputs than those living on the ground. Overall, lower availability of allochthonous inputs did not affect community‐wide metrics and niche width of predators. However, the niche width of some spider families had very low overlap between treatments, and others had wider isotopic niches in the control than exclusion treatment. Most of the C and N in predators living in control stretches came from aquatic subsidies, and those predators living in exclusion treatments switched their diets to terrestrial sources, showing a preference of predators for allochthonous subsidies. 4.Our results suggest that allochthonous subsidies are also relevant to tropical fauna living upon vegetation. Moreover, allochthonous resources may amplify the niche dimension of certain predators, or considerably change the trophic niche of others. Our study highlights the importance of including modern isotopic tools in elucidating the role of allochthonous resources on the patterns of trophic structure and niche dimensions of consumers from donor ecosystems. This article is protected by copyright. All rights reserved.
      PubDate: 2015-11-21T02:28:51.498297-05:
      DOI: 10.1111/1365-2656.12475
       
  • Changing climate cues differentially alter zooplankton dormancy dynamics
           across latitudes
    • Authors: Natalie T. Jones; Benjamin Gilbert
      Abstract: 1.In seasonal climates, dormancy is a common strategy that structures biodiversity and is necessary for the persistence of many species. Climate change will likely alter dormancy dynamics in zooplankton, the basis of aquatic food webs, by altering two important hatching cues: mean temperatures during the ice‐free season, and mean day length when lakes become ice free. Theory suggests that these changes could alter diversity, hatchling abundances and phenology within lakes, and that these responses may diverge across latitudes due to differences in optimal hatching cues and strategies. 2.To examine the role of temperature and day length on hatching dynamics, we collected sediment from 25 lakes across a 1800 km latitudinal gradient and exposed sediment samples to a factorial combination of two photoperiods (12 and 16 hours) and two temperatures (8°C and 12 °C) representative of historical southern (short photoperiod, warm) and northern (long photoperiod, cool) lake conditions. We tested whether sensitivity to these hatching cues varies by latitudinal origin and differs among taxa. 3.Higher temperatures advanced phenology for all taxa, and these advances were greatest for cladocerans followed by copepods and rotifers. Although phenology differed among taxa, the effect of temperature did not vary with latitude. The latitudinal origin of the egg bank influenced egg abundance and hatchling abundance and diversity, with these latter effects varying with taxa, temperature and photoperiod. 4.Copepod hatchling abundances peaked at mid latitudes in the high temperature and long photoperiod treatments, whereas hatchling abundances of other zooplankton were greatest at low latitudes and high temperature. The overall diversity of crustacean zooplankton (copepods and cladocerans) also reflected distinct responses of each taxa to our treatments, with the greatest diversity occurring at mid latitudes (~56° N) in the shorter photoperiod treatment. 5.Our results demonstrate that hatching cues differ for broad taxonomic groups that vary in developmental and life‐history strategies. These differences are predicted to drive latitude‐specific shifts in zooplankton emergence with climate change, and could alter the base of aquatic food webs. This article is protected by copyright. All rights reserved.
      PubDate: 2015-11-21T02:27:18.491941-05:
      DOI: 10.1111/1365-2656.12474
       
  • Climate and habitat interact to shape the thermal reaction norms of
           breeding phenology across lizard populations
    • Abstract: 1.Substantial plastic variation in phenology in response to environmental heterogeneity through time in the same population has been uncovered in many species. However, our understanding of differences in reaction norms of phenology among populations from a given species remains limited. 2.Since the plasticity of phenological traits is often influenced by local thermal conditions, we expect local temperature to generate variation in the reaction norms between populations. 3.Here, we explored temporal variation in parturition date across 11 populations of the common lizard (Zootoca vivipara) from four mountain chains as a function of air temperatures during mid‐gestation. We characterized among‐population variation to assess how local weather conditions (mean and variance of ambient temperatures during mid‐gestation) and habitat openness (an index of anthropogenic disturbance) influence the thermal reaction norms of the parturition date. 4.Our results provide evidence of interactive effects of anthropogenic disturbance and thermal conditions, with earlier parturition dates in warmer years on average especially in closed habitats. 5.Variation in the reaction norms for parturition date was correlated with mean local thermal conditions at a broad geographical scale. However populations exposed to variable thermal conditions had flatter thermal reaction norms. 6.Assessing whether environmental heterogeneity drives differentiation among reaction norms is crucial to estimate the capacity of different populations to contend with projected climatic and anthropogenic challenges. This article is protected by copyright. All rights reserved.
      PubDate: 2015-11-21T02:23:56.037811-05:
      DOI: 10.1111/1365-2656.12473
       
  • Host infection history modifies co‐infection success of multiple
           parasite genotypes
    • Abstract: 1.Co‐infections by multiple parasite genotypes are common and have important implications for host‐parasite ecology and evolution through within‐host interactions. Typically, these infections take place sequentially and therefore, the outcome of co‐infection may be shaped by host immune responses triggered by previous infections. For example, in vertebrates specific immune responses play a central role in protection against disease over the course of life, but co‐infection research has mostly focused on previously uninfected individuals. 2.Here, we investigated whether sequential exposure and activation of host resistance in rainbow trout Oncorhynchus mykiss affects infection success and interactions between co‐infecting parasite genotypes of the trematode eye‐fluke Diplostomum pseudospathaceum. 3.In accordance with earlier results, we show that a simultaneous attack of two parasite genotypes facilitates parasite establishment in previously uninfected hosts. However, we find for the first time that this facilitation in co‐infection is lost in hosts with prior infection. 4.We conclude that vertebrate host infection history can affect the direction of within‐host parasite interactions. Our results may have significant implications for the evolution of co‐infections and parasite transmission strategies. This article is protected by copyright. All rights reserved.
      PubDate: 2015-11-21T02:23:08.774991-05:
      DOI: 10.1111/1365-2656.12472
       
  • A trait‐based metric sheds new light on the nature of the body
           size‐depth relationship in the deep sea
    • Authors: B. L. Mindel; T. J. Webb, F. C. Neat, J. L. Blanchard
      Abstract: 1.Variation within species is an often‐overlooked aspect of community ecology, despite the fact that the ontogenetic structure of populations influences processes right up to the ecosystem level. Accounting for traits at the individual level is an important advance in the implementation of trait‐based approaches in understanding community structure and function. 2.We incorporate individual‐ and species‐level traits into one succinct assemblage structure metric, fractional size, which is calculated as the length of an individual divided by its potential maximum length. We test the implementation of fractional size in demersal fish assemblages along a depth gradient in the deep sea. We use data from an extensive trawl survey at depths of 300‐2030m on the continental slope of the Rockall Trough, Northeast Atlantic, to compare changes in fractional size structure along an environmental gradient to those seen using traditional taxonomic and trait‐based approaches. 3.The relationship between fractional size and depth was particularly strong, with the overall pattern being an increase with depth, implying that individuals move deeper as they grow. Body size increased with depth at the intra‐specific and assemblage levels. Fractional size, size structure and species composition all varied among assemblages, and this variation could be explained by the depth that the assemblage occupied. 4.The inclusion of individual‐level traits and population fractional size structure adds to our understanding at the assemblage level. Fractional size, or where an individual is in its growth trajectory, appears to be an especially important driver of assemblage change with depth. This has implications for understanding fisheries impacts in the deep sea and how these impacts may propagate across depths. This article is protected by copyright. All rights reserved.
      PubDate: 2015-11-12T08:10:13.921271-05:
      DOI: 10.1111/1365-2656.12471
       
  • Tick exposure and extreme climate events impact survival and threaten the
           persistence of a long‐lived lizard
    • Authors: Alice R. Jones; C Michael Bull, Barry W. Brook, Konstans Wells, Kenneth H. Pollock, Damien A. Fordham
      Abstract: 1.Assessing the impacts of multiple, often synergistic, stressors on the population dynamics of long‐lived species is becoming increasingly important due to recent and future global change. 2.Tiliqua rugosa (sleepy lizard) is a long‐lived skink (>30 years) that is adapted to survive in semi‐arid environments with varying levels of parasite exposure and highly seasonal food availability. We used an exhaustive database of 30‐years of capture‐mark‐recapture records to quantify the impacts of both parasite exposure and environmental conditions on the lizard's survival rates and long‐term population dynamics. 3.Lizard abundance was relatively stable throughout the study period; however there were changing patterns in adult and juvenile apparent survival rates, driven by spatial and temporal variation in levels of tick exposure and temporal variation in environmental conditions. Extreme weather events during the winter and spring seasons were identified as important environmental drivers of survival. 4.Climate models predict a dramatic increase in the frequency of extreme hot and dry winter and spring seasons in our South Australian study region; from a contemporary probability of 0.17 up to 0.47 ‐ 0.83 in 2080 depending on the emissions scenario. Our stochastic population model projections showed that these future climatic conditions will induce a decline in the abundance of this long‐lived reptile of up to 67% within 30 years from 2080, under worst case scenario modelling. 5.The results have broad implications for future work investigating the drivers of population dynamics and persistence. We highlight the importance of long‐term datasets and accounting for synergistic impacts between multiple stressors. We show that predicted increases in the frequency of extreme climate events have the potential to considerably and negatively influence a long‐lived species, which might previously have been assumed to be resilient to environmental perturbations. This article is protected by copyright. All rights reserved.
      PubDate: 2015-11-12T08:08:34.31838-05:0
      DOI: 10.1111/1365-2656.12469
       
  • A benign juvenile environment reduces the strength of antagonistic
           pleiotropy and genetic variation in the rate of senescence
    • Abstract: 1.The environment can play an important role in the evolution of senescence because the optimal allocation between somatic maintenance and reproduction depends on external factors influencing life expectancy. 2.The aims of this study were to experimentally test whether environmental conditions during early life can shape senescence schedules, and if so, to examine whether variation among individuals or genotypes with respect to the degree of ageing differs across environments. 3.We tested life‐history plasticity and quantified genetic effects on the pattern of senescence across different environments within a reaction norm framework by using an experiment on the three‐spined stickleback (Gasterosteus aculeatus, Linnaeus) in which F1 families originating from a wild annual population experienced different temperature regimes. 4.Male sticklebacks that had experienced a more benign environment earlier in life subsequently reduced their investment in carotenoid‐based sexual signals early in the breeding season, and consequently senesced at a slower rate later in the season, compared to those that had developed under harsher conditions. This plasticity of ageing was genetically determined. Both antagonistic pleiotropy and genetic variation in the rate of senescence were evident only in the individuals raised in the harsher environment. 5.The experimental demonstration of genotype‐by‐environment interactions influencing the rate of reproductive senescence provides interesting insights into the role of the environment in the evolution of life‐histories. The results suggest that benign conditions weaken the scope for senescence to evolve, and that the dependence on the environment may maintain genetic variation under selection. This article is protected by copyright. All rights reserved.
      PubDate: 2015-11-12T08:07:02.056005-05:
      DOI: 10.1111/1365-2656.12468
       
  • Energetic constraint of non‐monotonic mass change during offspring
           growth: a general hypothesis and application of a new tool
    • Authors: Jennifer M. Arnold; Ian C. T. Nisbet, Stephen A. Oswald
      Abstract: 1. Postnatal growth is an important life‐history trait and can be a sensitive indicator of ecological stress. For over 50 years, monotonic (never‐decreasing) growth has been viewed as the predominant trajectory of postnatal mass change in most animal species, notably among birds. However, prevailing analytical approaches and energetic constraints may limit detection of non‐monotonic (or multi‐phasic), determinate growth patterns, such as mass recession in birds (weight‐loss prior to fledging, preceded by overshooting adult mass), which is currently believed to be restricted to few taxa. 2. Energetic surplus and shortfall are widespread conditions that can directly influence the degree of mass overshooting and recession. Thus, we hypothesize that in many species prevailing energetic constraints force mass change away from a fundamental non‐monotonic trajectory to instead follow a monotonic curve. 3. We observed highly non‐monotonic, mass change trajectories (overshooting adult mass by up to almost 20%) among common tern Sterna hirundo chicks, a well‐studied species long‐established as growing monotonically. We quantified the prevalence and magnitude of non‐monotonic mass change prior to fledging for 313 common tern chicks that successfully fledged from two discrete populations in multiple years. We used a new approach for analysing non‐monotonic curves to examine differences in mass change trajectories between populations under contrasting abiotic (freshwater versus saltwater) and biotic stresses (low rates of food provisioning). 4. Some degree of mass recession occurred in 73% of all study chicks. Overshooting adult mass followed by extensive mass recession was most prevalent at our freshwater colony, being detected among 34 ‐ 38% of chicks annually. Non‐monotonic trajectories were less marked in populations experiencing ecological stress and among lower quality individuals. Chicks that were provisioned at higher rates were more likely to both overshoot adult mass and experience subsequent mass recession. 5. Our results provide strong support in common terns for the hypothesis that non‐monotonic trajectories are the fundamental pattern of mass change but are constrained to be monotonic under energetic shortfall. This justifies future tests of the generality of this hypothesis across a broad range of taxa. We also demonstrate a recent analytical tool that prevents routine fitting of monotonic curves without prior investigation of non‐monotonic trends. This article is protected by copyright. All rights reserved.
      PubDate: 2015-11-06T02:56:40.774168-05:
      DOI: 10.1111/1365-2656.12467
       
  • Phase‐dependent climate‐predator interactions explain three
           decades of variation in neonatal caribou survival
    • Abstract: 1.Climate can have direct and indirect effects on population dynamics via changes in resource competition or predation risk, but this influence can be modulated by density‐ or phase‐dependent processes. We hypothesized that for ungulates, climatic conditions close to parturition have a greater influence on the predation risk of neonates during population declines, when females are already under nutritional stress triggered by food limitation. 2.We examined the presence of phase‐dependent climate‐predator interactions on neonatal ungulate survival by comparing spatial and temporal fluctuations in climatic conditions, cause specific mortality, and per capita resource limitation. We determined cause‐specific fates of 1384 caribou (Rangifer tarandus) from 10 herds in Newfoundland, spanning more than 30 years during periods of numerical increase and decline, while exposed to predation from black bears (Ursus americanus) and coyotes (Canis latrans). 3.We conducted Cox proportional hazards analysis for competing risks, fit as a function of weather metrics, to assess pre‐ and post‐partum climatic influences on survival on herds in population increase and decline phases. We used cumulative incidence functions to compare temporal changes in risk from predators. 4.Our results support our main hypothesis; when caribou populations increased, weather conditions preceding calving were the main determinants of cause‐specific mortality, but when populations declined, weather conditions during calving also influenced predator‐driven mortality. Cause‐specific analysis showed that weather conditions can differentially affect predation risk between black bears and coyotes with specific variables increasing the risk from one species and decreasing the risk from the other. 5.For caribou, nutritional stress appears to increase predation risk on neonates, an interaction which is exacerbated by susceptibility to climatic events. These findings support the phase‐dependent climate‐predator (PDCP) interactions framework, where maternal body condition influences susceptibility to climate‐related events and, subsequently, risk from predation. This article is protected by copyright. All rights reserved.
      PubDate: 2015-11-03T09:51:52.094761-05:
      DOI: 10.1111/1365-2656.12466
       
  • Onset of autumn shapes the timing of birth in Pyrenean chamois more than
           onset of spring
    • Authors: Charlotte Kourkgy; Mathieu Garel, Joel Appolinaire, Anne Loison, Carole Toigo
      Abstract: 1.In seasonal environments, birth dates are a central component for a species’ life history, with potential long‐term fitness consequences. Yet our understanding of selective pressures of environmental changes on birth dates is limited in wild mammals due to the difficulty of data collection. In a context of rapid climate change, the question of a possible mismatch between plant phenology and birth phenology also remains unanswered for most species. 2.We assessed whether and how the timing of birth in a mountain mammal (isard, Rupicapra pyrenaica) tracked changes in plant growing season, accounting for maternal traits, individual heterogeneity, and population density. We not only focused on spring conditions but also assessed to what extent onset of autumn can be a driver of phenological biological events and compared the magnitude of the response to the magnitude of the environmental changes. We relied on a 22‐year study based on intensively monitored marked individuals of known age. 3.Births were highly synchronized (80% of kids born within 25 days) and highly repeatable (84%; among‐females variation of 9.6 days, withinfemale variation of 4.2 days). Individual phenotypic plasticity allows females to respond rapidly to inter‐annual changes in plant phenology but did not prevent the existence of a mismatch: a 10‐day advance in the autumn or spring plant phenology led to 3.9 and 1.3 days advance in birth dates, respectively. 4.Our findings suggest that plant phenology may act as a cue to induce important stages of the reproductive cycle (e.g., conception and gestation length), subsequently affecting parturition dates, and stressed the importance of focusing on long‐term changes during spring for which females may show much lower adaptive potential than during autumn. These results also question the extent to which individual plasticity along with high heterogeneity among individuals will allow species to cope with demographic consequences of climate changes. This article is protected by copyright. All rights reserved.
      PubDate: 2015-10-27T02:05:55.9768-05:00
      DOI: 10.1111/1365-2656.12463
       
  • Top predators and habitat complexity alter an intraguild predation module
           in pond communities
    • Authors: Thomas L. Anderson; Raymond D. Semlitsch
      Abstract: Predator diversity and habitat complexity frequently influence species interactions at lower trophic levels, yet their joint investigation has been performed infrequently despite the demonstrated importance of each individual factor. We investigated how different top predators and varying habitat complexity influence the function of an intraguild predation module consisting of two larval salamanders, intraguild predator Ambystoma annulatum and intraguild prey A. maculatum. We manipulated predator food webs and habitat complexity in outdoor mesocosms. Top predators significantly influenced body condition and survival of A. annulatum, but habitat complexity had minimal effects on either response. A three‐way interaction among the covariates top predator identity, habitat complexity and A. annulatum survival influenced body condition and survival of A. maculatum via a density mediated indirect effect. Different top predator combinations had variable effects in different habitat complexity treatments on intraguild predator (A. annulatum) survival that subsequently influenced intraguild prey (A. maculatum) body condition and survival. Future work should consider how different top predators influence other food web components, which should vary due to predator attributes and the physical environments in which they co‐occur. This article is protected by copyright. All rights reserved.
      PubDate: 2015-10-17T09:16:33.031373-05:
      DOI: 10.1111/1365-2656.12462
       
  • Community structure influences species’ abundance along
           environmental gradients
    • Authors: A.P. Eloranta; I.P. Helland, O.T. Sandlund, T Hesthagen, O Ugedal, A.G. Finstad
      Abstract: Species response to abiotic environmental variation can be influenced by local community structure and interspecific interactions, particularly in restricted habitats such as islands and lakes. In temperate lakes, future increase in water temperature and runoff of terrestrial (allochthonous) dissolved organic carbon (DOC) are predicted to alter community composition and the overall ecosystem productivity. However, little is known about how the present community structure and abiotic environmental variation interact to affect the abundance of native fish populations. We used a space‐for‐time approach to study how local community structure interact with lake morphometric and climatic characteristics (i.e., temperature and catchment productivity) to affect brown trout (Salmo trutta L.) yield in 283 Norwegian lakes located in different biogeographical regions. Brown trout yield (based on data from standardized survey gill net fishing; g 100 m−2 gill net night−1) was generally lower in lakes where other fish species were present than in lakes with brown trout only. It showed an overall negative relationship with increasing temperature and a positive relationship with lake shoreline complexity. Brown trout yield was also negatively correlated with DOC load (measured using Normalized Difference Vegetation Index as a proxy) and lake size and depth (measured using terrain slope as a proxy), but only in lakes where other fish species were present. The observed negative response of brown trout yield to increasing DOC load and proportion of the pelagic open‐water area is likely due to restricted (littoral) niche availability and competitive dominance of more pelagic fishes such as Arctic charr (Salvelinus alpinus (L.)). Our study highlights that, through competitive interactions, the local community structure can influence the response of a species’ abundance to variation in abiotic conditions. Changes in biomass and niche use of top predators (such as the brown trout), associated with predicted changes in direct and indirect climatic factors, may have further influences on the structure and function of temperate lake ecosystems. This article is protected by copyright. All rights reserved.
      PubDate: 2015-10-17T09:15:49.110956-05:
      DOI: 10.1111/1365-2656.12461
       
  • Resource type influences the effects of reserves and connectivity on
           ecological functions
    • Authors: Nicholas A. Yabsley; Andrew D. Olds, Rod M. Connolly, Tyson S. H. Martin, Ben L. Gilby, Paul S. Maxwell, Chantal M. Huijbers, David S Schoeman, Thomas A. Schlacher
      Abstract: 1.Connectivity is a pivotal feature of landscapes that affects the structure of populations and the functioning of ecosystems. It is also a key consideration in conservation planning. But the potential functional effects of landscape connectivity are rarely evaluated in a conservation context. 2.The removal of algae by herbivorous fish is a key ecological function on coral reefs that promotes coral growth and recruitment. Many reef herbivores are harvested and some use other habitats (like mangroves) as nurseries or feeding areas. Thus, the effects of habitat connectivity and marine reserves can jointly promote herbivore populations on coral reefs thereby influencing reef health. 3.We used a coral reef seascape in eastern Australia to test whether seascape connectivity and reserves influence herbivory. We measured herbivore abundance and rates of herbivory (on turf algae and macroalgae) on reefs that differed in both their level of connectivity to adjacent mangrove habitats, and their level of protection from fishing. 4.Reserves enhanced the biomass of herbivorous fish on coral reefs in all seascape settings and promoted consumption of turf algae. Consumption of turf algae was correlated with the biomass of surgeonfish that are exploited outside reserves. By contrast, both reserve status and connectivity influenced herbivory on macroalgae. Consumption of macroalgae was greatest on fished reefs that were far from mangroves, and was not strongly correlated with any fish species. 5.Our findings demonstrate that landscape connectivity and reserve status can jointly affect the functioning of ecosystems. Moreover, we show that reserve and connectivity effects can differ markedly depending on resource type (in this case turf algae vs macroalgae). The effectiveness of conservation initiatives will therefore depend on our ability to understand how these multiple interactive effects structure the distribution of ecological functions. These findings have wider implications for the spatial conservation of heterogeneous environments and strengthen the case that the impact of conservation on ecosystem functioning is contingent on how reserves are positioned in landscapes. This article is protected by copyright. All rights reserved.
      PubDate: 2015-10-17T09:15:26.907173-05:
      DOI: 10.1111/1365-2656.12460
       
  • Influences of sampling effort on detected patterns and structuring
           processes of a Neotropical plant‐hummingbird network
    • Abstract: Virtually all empirical ecological interaction networks to some extent suffer from undersampling. However, how limitations imposed by sampling incompleteness affect our understanding of ecological networks is still poorly explored, which may hinder further advances in the field. Here, we use a plant‐hummingbird network with unprecedented sampling effort (2,716 hours of focal observations) from the Atlantic Rainforest in Brazil, to investigate how sampling effort affects the description of network structure (i.e. widely used network metrics) and the relative importance of distinct processes (i.e. species abundances vs traits) in determining the frequency of pairwise interactions. By dividing the network into time slices representing a gradient of sampling effort, we show that quantitative metrics, such as interaction evenness, specialization (H2’), weighted nestedness (wNODF) and modularity (Q; QuanBiMo algorithm), were less biased by sampling incompleteness than binary metrics. Furthermore, the significance of some network metrics changed along the sampling effort gradient. Nevertheless, the higher importance of traits in structuring the network was apparent even with small sampling effort. Our results (i) warn against using very poorly sampled networks as this may bias our understanding of networks, both their patterns and structuring processes, (ii) encourage the use of quantitative metrics little influenced by sampling when performing spatio‐temporal comparisons, and (iii) indicate that in networks strongly constrained by species traits, such as plant‐hummingbird networks, even small sampling is sufficient to detect their relative importance for the structure of interactions. Finally, we argue that similar effects of sampling are expected for other highly specialized subnetworks. This article is protected by copyright. All rights reserved.
      PubDate: 2015-10-17T09:14:59.336288-05:
      DOI: 10.1111/1365-2656.12459
       
  • Temperature‐associated habitat selection in a cold‐water
           marine fish
    • Authors: Carla Freitas; Esben Moland Olsen, Halvor Knutsen, Jon Albretsen, Even Moland
      Abstract: Habitat selection is a complex process, which involves behavioural decisions guided by the multiple needs and constraints faced by individuals. Climate‐induced changes in environmental conditions may alter those trade‐offs and resulting habitat use patterns. In this study we investigated the effect of sea temperature on habitat selection and habitat use of acoustically tagged Atlantic cod (Gadus morhua) at the Norwegian Skagerrak coast. Significant relationships between ocean temperature and habitat selection and use were found. Under favourable sea temperature thresholds (< 16°C), cod selected vegetated habitats, such as eelgrass and macroalgae beds, available in shallow areas. Selection for those habitats was especially high at night, when cod tended to ascend to shallower areas, presumably to feed. Selection and use of those habitats decreased significantly as temperature rose. Under increased sea surface temperature conditions, cod were absent from vegetated shallow habitats, both during the day and night, and selected instead non‐vegetated rocky bottoms and sand habitats, available in deeper, colder areas. This study shows the dynamic nature of habitat selection and strongly suggests that cod in this region have to trade off food availability against favourable temperature conditions. Future increases in ocean temperature are expected to further influence the spatial behaviour of marine fish, potentially affecting individual fitness and population dynamics. This article is protected by copyright. All rights reserved.
      PubDate: 2015-10-17T09:14:24.047631-05:
      DOI: 10.1111/1365-2656.12458
       
  • Ecological diversification associated with the pharyngeal jaw diversity of
           Neotropical cichlid fishes
    • Authors: Edward D. Burress
      Abstract: 1.Innovations can facilitate bursts of diversification by increasing access to novel resources and the attainment of novel functional designs. Pharyngognathy, exhibited by highly diverse groups such as wrasses and cichlid fishes, is hypothesized to increase foraging capacity and efficiency. 2.Here, I test the hypothesis that pharyngeal jaw shape and tooth morphology is adaptive in an ecologically diverse radiation of Neotropical cichlid fishes that spans North, Central, and South America. 3.I partitioned species into generalized trophic guilds using published stomach content analyses and quantified shape variation of the lower pharyngeal jaw using geometric morphometrics. Additionally, I tested for convergence in LPJ shape and trophic guild by mapping the phylogeny onto the principal components and testing for shifts towards similar evolutionary regimes. 4.Major LPJ shape variation included the length and orientation (i.e., narrow or wide) of the lateral processes and length of the medial process, which varied based on the proportion of fishes and plants consumed. Pharyngeal tooth number, diversity, and the frequency of tooth types were not evenly distributed among trophic guilds. There were seven distinct evolutionary regimes that converged upon four optima. 5.Pharyngeal jaw diversification is associated with the exploitation of novel resources among Neotropical cichlids such that pharyngeal specialization has increased access to otherwise poorly accessible resources, such as resources that are difficult to crush (e.g., hard shelled organisms) and assimilate (e.g., algae). This article is protected by copyright. All rights reserved.
      PubDate: 2015-10-17T09:02:51.321324-05:
      DOI: 10.1111/1365-2656.12457
       
  • Experimental manipulation of floral scent bouquets restructures
           flower–visitor interactions in the field
    • Abstract: A common structural feature of natural communities is the non‐random distribution of pairwise interactions between organisms of different trophic levels. For plant–animal interactions, it is predicted that both stochastic processes and functional plant traits that facilitate or prevent interactions are responsible for these patterns. However, unbiased manipulative field experiments that rigorously test the effects of individual traits on community structure are lacking. We address this gap by manipulating floral scent bouquets in the field. Manipulation of floral scent bouquets led to quantitative as well as qualitative restructuring of flower–visitor networks, making them more generalized. Olfactometer trials confirmed both positive and negative responses to scent bouquets. Our results clearly show that the distribution of insect visitors to the two abundant study plant species reflects the insects' species‐specific preferences for floral scents, rather than for visual or morphological floral traits. Thus, floral scents may be of major importance in partitioning flower–visitor interactions. Integrating experimental manipulations of plant traits with field observations of interaction patterns thus represents a promising approach for revealing the processes that structure species assemblages in natural communities. Recently, network research moved from descriptive to mechanistic studies asking questions about the functional foundation of species interactions and community composition. This study is the first that directly characterizes the effect of an individual trait (floral scent bouquets) on the quantitative and qualitative distribution of plant‐animal interactions allowing conclusions about their co‐evolution and the maintenance of biodiversity.
      PubDate: 2015-10-02T01:08:53.543452-05:
      DOI: 10.1111/1365-2656.12441
       
  • Spatial overlap in a solitary carnivore: support for the
           land‐tenure, kinship, or resource dispersion hypotheses'
    • Authors: L. Mark Elbroch; Patrick E. Lendrum, Howard Quigley, Anthony Caragiulo
      Abstract: 1.There are several alternative hypotheses about the effects of territoriality, kinship, and prey availability on individual carnivore distributions within populations. The first is the land‐tenure hypothesis, which predicts that carnivores regulate their density through territoriality and temporal avoidance. The second is the kinship hypothesis, which predicts related individuals will be clumped within populations, and the third is the resource dispersion hypothesis, which suggests that resource richness may explain variable sociality, spatial overlap, or temporary aggregations of conspecifics. 2.Research on the socio‐spatial organization of animals is essential in understanding territoriality, intra‐ and inter‐specific competition, and contact rates that influence diverse ecology, including disease transmission between conspecifics and courtship behaviors. 3.We explored these hypotheses with data collected on a solitary carnivore, the cougar (Puma concolor), from 2005 to 2012 in the Southern Yellowstone Ecosystem, Wyoming, USA. We employed 27 annual home ranges for 13 cougars to test whether home range overlap was better explained by land‐tenure, kinship, resource dispersion, or some combination of the three. 4.We found support for both the land‐tenure and resource dispersion hypotheses, but not for kinship. Cougar sex was the primary driver explaining variation in home range overlap. Males overlapped significantly with females, whereas the remaining dyads (F‐F, M‐M) overlapped significantly less. In support for the resource dispersion hypothesis, hunting opportunity (the probability of a cougar killing prey in a given location) was often higher in overlapping than in non‐overlapping portions of cougar home ranges. In particular, winter hunt opportunity rather than summer hunt opportunity was higher in overlapping portions of female‐female and male‐female home ranges. 5.Our results may indicate that solitary carnivores are more tolerant of sharing key resources with unrelated conspecifics than previously believed, or at least during periods of high resource availability. Further, our results suggest that the resource dispersion hypothesis, which is typically applied to social species, is applicable in describing the spatial organization of solitary carnivores. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-23T02:25:42.445382-05:
      DOI: 10.1111/1365-2656.12447
       
  • Movement is the glue connecting home ranges and habitat selection
    • Abstract: 1.Animal space use has been studied by focusing either on geographic (e.g., home ranges, species’ distribution) or environmental (e.g., habitat use and selection) space. However, all patterns of space use emerge from individual movements, which are the primary means by which animals change their environment. 2.Individuals increase their use of a given area by adjusting two key movement components: the duration of their visit, and/or the frequency of re‐visits. Thus, in spatially heterogeneous environments animals exploit known, high‐quality resource areas by increasing their Residence Time (RT) in and/or decreasing their Time to Return (TtoR) to these areas. We expected that spatial variation in these two movement properties should lead to observed patterns of space use in both geographic and environmental spaces. We derived a set of 9 predictions linking spatial distribution of movement properties to emerging space use patterns. We predicted that, at a given scale, high variation in RT and TtoR among habitats leads to strong habitat selection, and that long RT and short TtoR result in a small home range size. 3.We tested these predictions using moose (Alces alces) GPS tracking data. We first modelled the relationship between landscape characteristics and movement properties. Then, we investigated how the spatial distribution of predicted movement properties (i.e., spatial autocorrelation, mean, and variance of RT and TtoR) influences home range size and hierarchical habitat selection. 4.In landscapes with high spatial autocorrelation of RT and TtoR, a high variation in both RT and TtoR occurred in home ranges. As expected, home range location was highly selective in such landscapes (i.e., 2nd‐order habitat selection); RT was higher and TtoR lower within the selected home range than outside, and moose home ranges were small. Within home ranges, a higher variation in both RT and TtoR was associated to higher selectivity among habitat types (i.e., 3rd‐order habitat selection). 5.Our findings show how patterns of geographic and environmental space use correspond to the two sides of a coin, linked by movement responses of individuals to environmental heterogeneity. By demonstrating the potential to assess the consequences of altering RT or TtoR (e.g., through human disturbance or climatic changes) on home range size and habitat selection, our work sets the basis for new theoretical and methodological advances in movement ecology. This article is protected by copyright. All rights reserved.
      PubDate: 2015-05-16T00:15:47.35042-05:0
      DOI: 10.1111/1365-2656.12394
       
  • Flying with the winds: differential migration strategies in relation to
           winds in moth and songbirds
    • First page: 1
      Abstract: The gamma Y moth selects to migrate in stronger winds compared to songbirds, enabling fast transport to distant breeding sites, but a lower precision in orientation as the moth allows itself to be drifted by the winds. Photo: Ian Woiwod. In Focus: Chapman, J.R., Nilsson, C., Lim, K.S., Bäckman, J., Reynolds, D.R. & Alerstam, T. (2015) Adaptive strategies in nocturnally migrating insects and songbirds: contrasting responses to winds. Journal of Animal Ecology, In press Insects and songbirds regularly migrate long distances across continents and seas. During these nocturnal migrations, they are exposed to a fluid medium, the air, in which they transport themselves by flight at similar speeds as the winds may carry them. It is crucial for an animal to select the most favourable flight conditions relative to winds to minimize the distance flown on a given amount of fuel and to avoid hazardous situations. Chapman et al. (2015a) showed contrasting strategies in how moths initiate migration predominantly under tailwind conditions, allowing themselves to drift to a larger extent and gain ground speed as compared to nocturnal songbird migrants. The songbirds use more variable flight strategies in relation to winds, where they sometimes allow themselves to drift, and at other occasions compensate for wind drift. This study shows how insects and birds have differentially adapted to migration in relation to winds, which is strongly dependent on their own flight capability, with higher flexibility enabling fine‐tuned responses to keep a time programme and reach a goal in songbirds compared to in insects. The gamma Y moth (Authographa gamma) selects to migrate in stronger winds compared to songbirds, enabling fast transport to distant breeding sites, but a lower precision in orientation as the moth allows itself to be drifted by the winds. Photo: Ian Woiwod.
      PubDate: 2015-12-09T10:10:27.015985-05:
      DOI: 10.1111/1365-2656.12450
       
  • EDITORIAL: Stuck in motion' Reconnecting questions and tools in
           movement ecology
    • First page: 5
      PubDate: 2015-12-09T10:10:36.000961-05:
      DOI: 10.1111/1365-2656.12464
       
  • Can habitat selection predict abundance'
    • Authors: Mark S. Boyce; Chris J. Johnson, Evelyn H. Merrill, Scott E. Nielsen, Erling J. Solberg, Bram Moorter
      First page: 11
      Abstract: Habitats have substantial influence on the distribution and abundance of animals. Animals’ selective movement yields their habitat use. Animals generally are more abundant in habitats that are selected most strongly. Models of habitat selection can be used to distribute animals on the landscape or their distribution can be modeled based on data of habitat use, occupancy, intensity of use, or counts of animals. When the population is at carrying capacity or in an ideal free distribution, habitat selection and related metrics of habitat use can be used to estimate abundance. If the population is not at equilibrium, models have the flexibility to incorporate density into models of habitat selection; but abundance might be influenced by factors influencing fitness that are not directly related to habitat thereby compromising the use of habitat‐based models for predicting population size. Scale and domain of the sampling frame, both in time and space, are crucial considerations limiting application of these models. Ultimately, identifying reliable models for predicting abundance from habitat data requires an understanding of the mechanisms underlying population regulation and limitation. This article is protected by copyright. All rights reserved.
      PubDate: 2015-03-16T02:44:25.832642-05:
      DOI: 10.1111/1365-2656.12359
       
  • Predicting the continuum between corridors and barriers to animal
           movements using Step Selection Functions and Randomized Shortest Paths
    • First page: 32
      Abstract: 1.The loss, fragmentation, and degradation of habitat everywhere on Earth prompt increasing attention to identifying landscape features that support animal movement (corridors) or impede it (barriers). Most algorithms used to predict corridors assume that animals move through preferred habitat either optimally (e.g. Least Cost Path), or as random‐walkers (e.g. Current Models), but neither extreme is realistic. 2.We propose that corridors and barriers are two sides of the same coin, and that animals experience landscapes as spatio‐temporally dynamic corridor‐barrier continua connecting (separating) functional areas where individuals fulfill specific ecological processes. Based on this conceptual framework, we propose a novel methodological approach that uses high‐resolution individual‐based movement data to predict corridor‐barrier continua with increased realism. 3.Our approach consists of two innovations. First, we use Step Selection Functions (SSF) to predict friction maps quantifying corridor‐barrier continua for tactical steps between consecutive locations. Second, we introduce to movement ecology the Randomized Shortest Path algorithm (RSP) which operates on friction maps to predict the corridor‐barrier continuum for strategic movements between functional areas. By modulating the parameter Ѳ, which controls the trade‐off between exploration and optimal exploitation of the environment, RSP bridges the gap between algorithms assuming optimal movements (when Ѳ approaches infinity, RSP is equivalent to LCP) or random‐walk (when Ѳ → 0, RSP → Current Models). 4.Using this approach, we identify migration corridors for GPS‐monitored wild reindeer (Rangifer t. tarandus) in Norway. We demonstrate that reindeer movement is best predicted by an intermediate value of Ѳ, indicative of a movement trade‐off between optimization and exploration. Model calibration allows identification of a corridor‐barrier continuum that closely fits empirical data, and demonstrates that RSP outperforms models that assume either optimality or random‐walk. 5.The proposed approach models the multi‐scale cognitive maps by which animals likely navigate real landscapes, and generalizes the most common algorithms for identifying corridors. Because sub‐optimal, but non‐random, movement strategies are likely widespread, our approach has the potential to predict more realistic corridor‐barrier continua for a wide range of species. This article is protected by copyright. All rights reserved.
      PubDate: 2015-05-07T03:56:33.585073-05:
      DOI: 10.1111/1365-2656.12386
       
  • How many routes lead to migration' Comparison of methods to assess and
           characterise migratory movements
    • First page: 54
      Abstract: 1.Decreasing rate of migration in several species as a consequence of climate change and anthropic pressure, together with increasing evidence of space‐use strategies intermediate between residency and complete migration, are very strong motivations to evaluate migration occurrence and features in animal populations. 2.The main goal of this paper was to perform a relative comparison between methods for identifying and characterising migration at the individual and population level on the basis of animal location data. 3.We classified 104 yearly individual trajectories from five populations of three deer species as migratory or non‐migratory, by means of three methods: seasonal home range overlap, spatio‐temporal separation of seasonal clusters, and the Net Squared Displacement (NSD) method. For migratory cases, we also measured timing and distance of migration and residence time on the summer range. Finally, we compared the classification in migration cases across methods and populations. 4.All methods consistently identified migration at the population level, i.e., they coherently distinguished between complete or almost complete migratory populations and partially migratory populations. However, in the latter case, methods coherently classified only about 50% of the single cases, i.e. they classified differently at the individual‐animal level. We therefore infer that the comparison of methods may help point to ‘less‐stereotyped’ cases in the residency‐to‐migration continuum. For cases consistently classified by all methods, no significant differences were found in migration distance, or residence time on summer ranges. Timing of migration estimated by NSD was earlier than by the other two methods, both for spring and autumn migrations. 5.We suggest 3 steps to identify improper inferences from migration data, and to enhance understanding of intermediate space‐use strategies. We recommend: a) classifying migration behaviours using more than one method, b) performing sensitivity analysis on method parameters to identify the extent of the differences, and c) investigating inconsistently classified cases as these may often be ecologically interesting (i.e., less‐stereotyped migratory behaviours). This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-28T00:50:29.313141-05:
      DOI: 10.1111/1365-2656.12449
       
  • What is the animal doing' Tools for exploring behavioral structure in
           animal movements
    • Authors: Eliezer Gurarie; Chloe Bracis, Maria Delgado, Trevor D. Meckley, Ilpo Kojola, C. Michael Wagner
      First page: 69
      Abstract: 1.Movement data provide a window ‐ often our only window ‐ into the cognitive, social and biological processes that underlie the behavioral ecology of animals in the wild. Robust methods for identifying and interpreting distinct modes of movement behavior are of great importance, but complicated by the fact that movement data are complex, multivariate, and dependent. Many different approaches to exploratory analysis of movement have been developed to answer similar questions and practitioners are often at a loss for how to choose an appropriate tool for a specific question. 2.We apply and compare four methodological approaches: first passage time (FPT), Bayesian partitioning of Markov models (BPMM), behavioral change point analysis (BCPA), and a fitted multi‐state random walk (MRW) to three simulated tracks and two animal trajectories ‐ a sea lamprey (Petromyzon marinus) tracked for 12 hours and a wolf (Canis lupus) tracked for one year. 3.The simulations ‐ in which, respectively, velocity, tortuosity, and spatial bias change ‐ highlight the sensitivity of all methods to model misspecification. Methods that do not account for autocorrelation in the movement variables lead to spurious change points while methods that do not account for spatial bias completely miss changes in orientation. We make suggestions towards unifying directions for methodological advances. 4.When applied to the animal data, the methods broadly agree on the structure of the movement behaviors. Important discrepancies, however, reect differences in the assumptions and nature of the outputs. Important trade‐offs are between the strength of the a priori assumptions (low in BCPA, high in MRW), complexity of output (high in the BCPA, low in the BPMM and MRW), and explanatory potential (highest in the MRW). 5.The animal track analysis suggests some general principles for the exploratory analysis of movement data, including ways to exploit the strengths of the various methods. We argue for close and detailed exploratory analysis of movement before fitting complex movement models. This article is protected by copyright. All rights reserved.
      PubDate: 2015-04-23T09:48:38.045866-05:
      DOI: 10.1111/1365-2656.12379
       
  • Tackling extremes: Challenges for ecological and evolutionary research on
           extreme climatic events
    • Authors: Liam D. Bailey; Martijn de Pol
      First page: 85
      Abstract: 1.Extreme climatic events (ECEs) are predicted to become more frequent as the climate changes. A rapidly increasing number of studies ‐ though few on animals ‐ suggest that the biological consequences of ECEs can be severe. 2.However, ecological research on the impacts of extreme climatic events (ECEs) has been limited by a lack of cohesiveness and structure. ECEs are often poorly defined and have often been confusingly equated with climatic variability, making comparison between studies difficult. Additionally, a focus on short‐term studies has provided us with little information on the long‐term implications of ECEs, and the descriptive and anecdotal nature of many studies has meant it is still unclear what the key research questions are. 3.Synthesizing the current state of work is essential to identify ways to make progress. We conduct a synthesis of the literature and discuss conceptual and practical challenges faced by research on ECEs. 4.We consider three steps to advance research. First, we discuss the importance of choosing an ECE definition and identify the pros and cons of ‘climatological’ and ‘biological’ definitions of ECEs. Second, we advocate research beyond short‐term descriptive studies to address questions concerning the long‐term implications of ECEs, focussing on selective pressures and phenotypically plastic responses and how they might differ from responses to a changing climatic mean. Finally, we encourage a greater focus on multi‐event studies that help us understand the implications of changing patterns of ECEs, through the combined use of modelling, experimental and observational field studies. 5.This paper aims to open a discussion on the definitions, questions and methods currently used to study ECEs, which will lead to a more cohesive approach to future ECE research. This article is protected by copyright. All rights reserved.
      PubDate: 2015-10-03T07:42:32.260903-05:
      DOI: 10.1111/1365-2656.12451
       
  • Edge effects and Geometric Constraints: a Landscape‐level Empirical
           Test
    • First page: 97
      Abstract: Edge effects are pervasive in landscapes yet their causal mechanisms are still poorly understood. Traditionally, edge effects have been attributed to differences in habitat quality along the edge‐interior gradient of habitat patches, under the assumption that no edge effects would occur if habitat quality was uniform. This assumption was questioned recently after the recognition that geometric constraints tend to reduce population abundances near the edges of habitat patches, the so‐called “geometric edge effect” (GEE). Here we present the first empirical, landscape‐level evaluation of the importance of the GEE in shaping abundance patterns in fragmented landscapes. Using a dataset on the distribution of small mammals across 18 forest fragments, we assessed whether the incorporation of the GEE into the analysis changes the interpretation of edge effects and the degree to which predictions based on the GEE match observed responses. Quantitative predictions were generated for each fragment using simulations that took into account home range, density and matrix use for each species. The incorporation of the GEE into the analysis changed substantially the interpretation of overall observed edge responses at the landscape scale. Observed abundances alone would lead to the conclusion that the small mammals as a group have no consistent preference for forest edges or interiors, and that the black‐eared opossum Didelphis aurita (a numerically dominant species in the community) has on average a preference for forest interiors. In contrast, incorporation of the GEE suggested that the small mammal community as a whole has a preference for forest edges, whereas D. aurita has no preference for forest edges or interiors. Unexplained variance in edge responses was reduced by the incorporation of GEE, but remained large, varying greatly on a fragment‐by‐fragment basis. This study demonstrates how to model and incorporate the GEE in analyses of edge effects, and that this incorporation is necessary to properly interpret edge effects in landscapes. It also suggests that geometric constraints alone are unlikely to explain the variability in edge responses of a same species among different areas, highlighting the need to incorporate other ecological factors into explanatory models of edge effects. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-18T03:38:27.718009-05:
      DOI: 10.1111/1365-2656.12430
       
  • Home is where the shell is: predicting turtle home range sizes
    • Authors: Alex Slavenko; Yuval Itescu, Flora Ihlow, Shai Meiri
      First page: 106
      Abstract: 1.Home range is the area traversed by an animal in its normal activities. The size of home ranges is thought to be tightly linked to body size, through size effect on metabolic requirements. Due to the structure of Eltonian food pyramids, home range sizes of carnivores are expected to exceed those of herbivorous species. The habitat may also affect home range size, with reduced costs of locomotion or lower food abundance in e.g., aquatic habitats selecting for larger home ranges. Furthermore, home range of males in polygamous species may be large due to sexual selection for increased reproductive output. 2.Comparative studies on home range sizes have rarely been conducted on ectotherms. Because ectotherm metabolic rates are much lower than those of endotherms, energetic considerations of metabolic requirements may be less important in determining the home range sizes of the former, and other factors such as differing habitats and sexual selection may have an increased effect. 3.We collected literature data on turtle home range sizes. We used phylogenetic generalised least squares analyses to determine whether body mass, sex, diet, habitat and social structure, affect home range size. 4.Turtle home range size increases with body mass. However, body mass explains relatively little of the variation in home range size. Aquatic turtles have larger home ranges than semiaquatic species. Omnivorous turtles have larger home ranges than herbivores and carnivores, but diet is not a strong predictor. Sex and social structure are unrelated to home range size. 5.We conclude that energetic constraints are not the primary factor that determines home range size in turtles, and energetic costs of locomotion in different habitats probably play a major role. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-23T02:27:03.510908-05:
      DOI: 10.1111/1365-2656.12446
       
  • Adaptive strategies in nocturnally migrating insects and songbirds:
           contrasting responses to wind
    • First page: 115
      Abstract: 1. Animals that use flight as their mode of transportation must cope with the fact that their migration and orientation performance is strongly affected by the flow of the medium they are moving in, i.e. by the winds. Different strategies can be used to mitigate the negative effects and benefit from the positive effects of a moving flow. The strategies an animal can use will be constrained by the relationship between the speed of the flow and the speed of the animal's own propulsion in relation to the surrounding air. 2. Here we analyse entomological and ornithological radar data from north‐western Europe to investigate how two different nocturnal migrant taxa, the noctuid moth Autographa gamma and songbirds, deal with wind by analysing variation in resulting flight directions in relation to the wind‐dependent angle between the animal's heading and track direction. 3. Our results, from fixed locations along the migratory journey, reveal different global strategies used by moths and songbirds during their migratory journeys. As expected, nocturnally migrating moths experienced a greater degree of wind drift than nocturnally migrating songbirds, but both groups were more affected by wind in autumn than in spring. 4. The songbirds’ strategies involve elements of both drift and compensation, providing some benefits from wind in combination with destination and time control. In contrast, moths expose themselves to a significantly higher degree of drift in order to obtain strong wind assistance, surpassing the songbirds in mean ground speed, at the cost of a comparatively lower spatiotemporal migratory precision. 5. Moths and songbirds show contrasting but adaptive responses to migrating through a moving flow, which are fine‐tuned to the respective flight capabilities of each group in relation to the wind currents they travel within. This article is protected by copyright. All rights reserved.
      PubDate: 2015-07-04T08:31:09.134657-05:
      DOI: 10.1111/1365-2656.12420
       
  • Multiple mating reveals complex patterns of assortative mating by
           personality and body size
    • First page: 125
      Abstract: 1.Understanding patterns of non‐random mating is central to predicting the consequences of sexual selection. Most studies quantifying assortative mating focus on testing for correlations among partners’ phenotypes in mated pairs. Few studies have distinguished between assortative mating arising from preferences for similar partners (expressed by all or a subset of the population), versus from phenotypic segregation in the environment. Also, few studies have assessed the robustness of assortative mating against temporal changes in social conditions. 2.We tracked multiple matings by stream water striders (Aquarius remigis) across variable social conditions to investigate mating patterns by both body size and behavioural type (personality). We documented temporal changes in partner availability and used a mixed model approach to analyse individual behaviours and changes in mating status recorded on an hourly basis. We assessed whether all or only a subset of individuals in the population expressed a tendency to mate with similar phenotypes. Our analyses took into account variation in the level of competition and in the phenotypes of available partners. 3.Males and females exhibited significant assortative mating by body size: the largest males and females, and the smallest males and females mated together more often than random. However, individuals of intermediate size were equally likely to mate with small, intermediate or large partners. Individuals also displayed two contrasting patterns of assortative mating by personality (activity level). Individuals generally mated preferentially with partners of similar activity level. However, beyond that general trend, individuals with more extreme personalities tended to exhibit disassortative mating: the most active males mated disproportionately with less active females, and the least active males tended to mate with more active females. 4.Our analyses thus revealed multiple, distinct patterns of non‐random mating. These mating patterns did not arise from differences in partner availability among individuals and were robust to temporal changes in social conditions. Hence mating patterns likely reflect mate preferences or arise from male – male competition coupled with sexual conflict. Our study also stresses the importance of accounting for variation in partner availability and demonstrates the influence of behavioural variation on mating patterns. This article is protected by copyright. All rights reserved.
      PubDate: 2015-08-31T10:16:42.440296-05:
      DOI: 10.1111/1365-2656.12436
       
  • Causes and consequences of repeatability, flexibility and individual
           fine‐tuning of migratory timing in pike
    • Authors: Petter Tibblin; Anders Forsman, Tobias Borger, Per Larsson
      First page: 136
      Abstract: Many organisms undertake migrations between foraging and breeding habitats and while it is assumed that reproductive timing affects fitness, little is known about the degree of individual consistency, and about the causes and consequences of individual variation in migratory timing in organisms other than birds. Here, we report on a 6‐year mark–recapture study, including 2048 individuals, of breeding migration in anadromous pike (Esox lucius), an iteroparous top‐predatory fish that displays homing behaviour. By repeated sampling across years at a breeding site, we first quantify individual variation both within and between breeding events and then investigate phenotypic correlates and fitness consequences of arrival timing to the breeding site. Our data demonstrate that males arrive before females, that large males arrive later than small males, that the timing of breeding migration varies among years and that individuals are consistent in their timing across years relative to other individuals in the population. Furthermore, data on return rates indicate that arrival time is under stabilizing viability selection, and that individuals who are more flexible in their timing of arrival during the first reproductive years survive longer compared with less flexible individuals. Finally, longitudinal data demonstrate that individuals consistently fine‐tune their arrival timing across years, showing that the timing of arrival to breeding sites is influenced by experience. These findings represent rare evidence of how between‐ and within‐individual variations in migratory timing across breeding events are correlated with phenotypic and fitness traits in an ecologically important keystone species. Our results emphasize the importance of considering variation in migratory timing both between and within individuals in studies investigating the fitness consequences of migratory behaviour and have implications for future management. This study provides rare evidence of phenotypic correlates and fitness consequences of individual variation of migratory timing in an aquatic top‐predatory fish.
      PubDate: 2015-09-28T00:59:32.197867-05:
      DOI: 10.1111/1365-2656.12439
       
  • Reefscapes of fear: predation risk and reef heterogeneity interact to
           shape herbivore foraging behavior
    • Authors: Laura B. Catano; Maria C. Rojas, Ryan J. Malossi, Joseph R. Peters, Michael R. Heithaus, James W. Fourqurean, Deron E. Burkepile
      First page: 146
      Abstract: Predators can exert strong direct and indirect effects on ecological communities by intimidating their prey. The nature of predation risk effects is often context dependent, but in some ecosystems these contingencies are often overlooked. Risk effects are often not uniform across landscapes or among species. Indeed, they can vary widely across gradients of habitat complexity and with different prey escape tactics. These context‐dependencies may be especially important for ecosystems such as coral reefs that vary widely in habitat complexity and have species‐rich predator and prey communities. With field experiments using predator decoys of the black grouper (Mycteroperca bonaci), we investigated how reef complexity interacts with predation risk to affect the foraging behavior and herbivory rates of large herbivorous fishes (e.g., parrotfishes and surgeonfishes) across four coral reefs in the Florida Keys (USA). In both high and low complexity areas of the reef we measured how herbivory changed with increasing distance from the predator decoy to examine how herbivorous fishes reconcile the conflicting demands of avoiding predation vs. foraging within a reefscape context. We show that with increasing risk, herbivorous fishes consumed dramatically less food (ca. 90 %) but fed at a faster rate when they did feed (ca. 26 %). Furthermore, we show that fishes foraging closest to the predator decoy were 40 % smaller than those that foraged at further distances. Thus, smaller individuals showed muted response to predation risk compared to their larger counterparts, potentially due to their decreased risk to predation or lower reproductive value (i.e., the asset protection principle). Habitat heterogeneity mediated risk effects differently for different species of herbivores, with predation risk more strongly suppressing herbivore feeding in more complex areas and for individuals at higher risk of predation. Predators appear to create a reefscape of fear that changes the size structure of herbivores towards smaller individuals, increases individual feeding rates, but suppresses overall amounts of primary producers consumed, potentially altering patterns of herbivory, an ecosystem process critical for healthy coral reefs. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-01T10:46:03.348313-05:
      DOI: 10.1111/1365-2656.12440
       
  • How to capture fish in a school' Effect of successive predator attacks
           on seabird feeding success
    • First page: 157
      Abstract: 1.Prey aggregations, such as fish schools, attract numerous predators. This typically leads to the formation of multi‐specific groups of predators. These aggregations can be seen both as a place of increased competition and as a place of possible facilitation between predators. Consequently, the functional role of such predator‐prey aggregation is uncertain, and its effect on individual feeding success is virtually unknown. 2.Using underwater film footages of different predators feeding on fish schools during the sardine run in South Africa, we directly measured the in‐situ feeding success of individual Cape gannets Morus capensis in different foraging situations. 3.We determined the types of Cape gannet attacks (direct plunge dive or plunge dive followed by underwater pursuit) and we measured the occurrences and timing of attacks from the different species (mostly Cape gannets and long‐beaked common dolphins Delphinus capensis). We also estimated the size of the targeted fish schools. These observations were complemented with a simulation model to evaluate the cumulative effect of successive predator attacks on the prey aggregation structure. 4.The probability to capture a fish in one feeding attempt by Cape gannets averaged 0.28. It was lower when gannets engaged in underwater prey pursuit after the plunge compared to direct plunge (0.13 vs. 0.36). We found no effect of the number of prey on gannets’ feeding success. However, the timing and frequency of attacks influenced strongly and positively the feeding success of individuals. The probability to capture a fish was the lowest (0.16) when no attack occurred in the few seconds (1‐15 s) prior to a dive, and the highest (~0.4, i.e. more than twice) when one or two attacks occurred during this time window. The simulation model showed that a prey aggregation disorganized just after an attack, and that the maximum of disturbance was obtained a few seconds after the initiation of the successive attacks. 5.Our study suggests that, in multi‐species predator assemblages, the cumulative effect (through disorganisation of school cohesiveness) of the multiple species attacking a prey aggregation may increase the feeding success of each individual. Therefore, facilitation between predators is likely to overcome competition in these multi‐specific assemblages. This article is protected by copyright. All rights reserved.
      PubDate: 2015-10-13T03:52:16.24444-05:0
      DOI: 10.1111/1365-2656.12455
       
  • Spatial scale and movement behaviour traits control the impacts of habitat
           fragmentation on individual fitness
    • Authors: Lorenzo Cattarino; Clive A. McAlpine, Jonathan R. Rhodes
      First page: 168
      Abstract: Habitat fragmentation, i.e., the breaking apart of habitat, can occur at multiple spatial scales at the same time, as a result of different land uses. Individuals of most species spend different amounts of times moving in different modes, during which they cover different distances and experience different fitness impacts. The scale at which fragmentation occurs interacts with the distance that individuals move in a particular mode to affect an individual's ability to find habitat. However, there is little knowledge of the fitness consequences of different scales of fragmentation for individuals with different traits of movement behaviour. This is critical to understand the mechanisms of persistence of different species in fragmented landscapes. The aim of this study is to quantify the impacts of habitat fragmentation at different scales on the fitness components (reproduction and survival) of individuals with different traits of movement behaviour. We developed a demographic model of individuals that adopt short and tortuous movements within foraging areas (foraging mode) and long and straight movements between foraging areas (searching mode). We considered individuals that adopt different movement modes with varying frequencies, inherently move different searching distances and experience different risks of mortality during searching. We then applied the model within a spatially‐explicit simulation framework where we varied simultaneously the degree of fragmentation within (fine scale) and between foraging areas (coarse scale). Fine‐scale fragmentation had a greater impact on reproduction and survival than coarse‐scale fragmentation, for those individuals with a low searching propensity. The impact of fine‐scale fragmentation on reproduction and survival interacted with the impact of coarse‐scale fragmentation on reproduction and survival, to affect the fitness of individuals with a high searching propensity, large inherent searching distances and high searching mortality rates. Habitat selection strongly mitigated the impact of the scale at which fragmentation occurred on individual fitness. Our findings suggest that the land use to target with conservation actions to reduce fragmentation, such as financial schemes that promote re‐vegetation or retention of standing vegetation, depends on the scale at which fragmentation occurs and the movement behaviour traits of the species of conservation concern. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-14T06:09:25.589053-05:
      DOI: 10.1111/1365-2656.12427
       
  • Cold‐seeking behaviour mitigates reproductive losses from fungal
           infection in Drosophila
    • Authors: Vicky L Hunt; Weihao Zhong, Colin D McClure, David T Mlynski, Elizabeth ML Duxbury, A Keith Charnley, Nicholas K Priest
      First page: 178
      Abstract: 1.Animals must tailor their life history strategies to suit the prevailing conditions and respond to hazards in the environment. Animals with lethal infections are faced with a difficult choice: to allocate more resources to reproduction and suffer higher mortality or to reduce reproduction with the expectation of enhanced immunity and late‐age reproduction. But, how they do this is largely unknown. 2.Here, we have investigated the temperature preference of the fruit fly, Drosophila melanogaster, during infection with the fungal pathogen, Metarhizium robertsii, and the consequences of temperature preference on life history traits. We have used multiple measurements to assess the fitness consequences of temperature including age‐specific changes in mortality rate and reproduction, providing more sensitive measures of accounting for variation in fitness with age. 3.We report that D. melanogaster optimizes its life history by exploiting thermal variation. Fungus‐infected fruit flies seek out cooler temperatures, which immediately reduces their fecundity but, ultimately, increases their lifetime reproductive success. Colder temperatures reduced fungal growth rates both in vivo and in vitro, indicating that cooler temperatures increased resistance to the infection. 4.By comparing life history responses in infected and control animals, we found that cold seeking in infected animals facilitates a trade off between early‐ and late‐age reproduction, but does not otherwise provide life history benefits that are specific to infected animals. These results indicate that cold‐seeking is a mechanism for reducing the reproductive costs of infection. In contrast, uninfected control flies prefer warmer temperatures that optimise reproductive success via a rapid propagation strategy. 5.These findings help explain how life history trade‐offs are mediated and how animals cope with infection, which will be increasingly important given the recent emergence of fungal pathogens and global climate change. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-01T10:57:29.954457-05:
      DOI: 10.1111/1365-2656.12438
       
  • Seasonal time constraints reduce genetic variation in life history traits
           along a latitudinal gradient
    • First page: 187
      Abstract: 1.Time constraints cause strong selection on life history traits, because populations need to complete their life cycles within a shorter time. We therefore expect lower genetic variation in these traits in high‐ than in low‐latitude populations, since the former are more time constrained. 2.The aim was to estimate life history traits and their genetic variation in an obligately univoltine damselfly along a latitudinal gradient of 2,730 km. 3.Populations were grown in the laboratory at temperatures and photoperiods simulating those at their place of origin. In a complementary experiment individuals from the same families were grown in constant temperature and photoperiod that mimicked average conditions across the latitude. 4.Development time and size was faster and smaller, respectively, and growth rate was higher at northern latitudes. Additive genetic variance was very low for life history traits and estimates for egg development time and larval growth rate showed significant decreases towards northern latitudes. The expression of genetic effects in life history traits differed considerably when individuals were grown in constant rather than simulated and naturally variable conditions. 5.Our results support strong selection by time constraints. They also highlight the importance of growing organisms in their native environment for correct estimates of genetic variance at their place of origin. Our results also suggest that the evolutionary potential of life history traits is very low at northern compared to southern latitudes, but that changes in climate could alter this pattern. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-03T04:52:02.482165-05:
      DOI: 10.1111/1365-2656.12442
       
  • Assessing the structure and temporal dynamics of seabird communities: the
           challenge of capturing marine ecosystem complexity
    • First page: 199
      Abstract: Understanding interspecific interactions, and the influences of anthropogenic disturbance and environmental change on communities, are key challenges in ecology. Despite the pressing need to understand these fundamental drivers of community structure and dynamics, only 17% of ecological studies conducted over the past three decades have been at the community level. Here, we assess the trophic structure of the procellariiform community breeding at South Georgia, to identify the factors that determine foraging niches and possible temporal changes. We collected conventional diet data from 13 sympatric species between 1974 and 2002, and quantified intra‐ and inter‐guild, and annual variation in diet between and within foraging habits. In addition, we tested the reliability of stable isotope analysis (SIA) of seabird feathers collected over a 13‐year period, in relation to those of their potential prey, as a tool to assess community structure when diets are diverse and there is high spatial heterogeneity in environmental baselines. Our results using conventional diet data identified a four‐guild community structure, distinguishing species that mainly feed on crustaceans; large fish and squid; a mixture of crustaceans, small fish and squid; or carrion. In total, Antarctic krill Euphausia superba represented 32%, and 14 other species a further 46% of the combined diet of all 13 predators, underlining the reliance of this community on relatively few types of prey. Annual variation in trophic segregation depended on relative prey availability; however, our data did not provide evidence of changes in guild structure associated with a suggested decline in Antarctic krill abundance over the past 40 years. Reflecting the differences in δ15N of potential prey (crustaceans vs. squid vs. fish and carrion), analysis of δ15N in chick feathers identified a three‐guild community structure that was constant over a 13‐year period, but lacked the trophic cluster representing giant petrels which was identified using conventional diet data. Our study is the first in recent decades to examine dietary changes in seabird communities over time. Conventional dietary analysis provided better resolution of community structure than SIA. However, δ15N in chick feathers, which reflected trophic (level) specialization, was nevertheless an effective and less time‐consuming means of monitoring temporal changes. In the past four decades, barely 20 published studies have attempted to describe seabird communities, only seven of which considered more than 10 species and none monitored temporal changes. This study is the first in recent decades to examine dietary changes in seabird communities over time.
      PubDate: 2015-10-06T09:14:29.916172-05:
      DOI: 10.1111/1365-2656.12434
       
  • Effects of management on aquatic tree‐hole communities in temperate
           forests are mediated by detritus amount and water chemistry
    • First page: 213
      Abstract: 1.Arthropod communities in water‐filled tree‐holes may be sensitive to impacts of forest management, for example via changes in environmental conditions such as resource input. 2.We hypothesized that increasing forest management intensity negatively affects arthropod abundance and richness and shifts community composition and trophic structure of tree‐hole communities. We predicted that this shift is caused by reduced habitat and resource availability at the forest stand scale as well as reduced tree‐hole size, detritus amount and changed water chemistry at the tree‐hole scale. 3.We mapped 910 water‐filled tree‐holes in two regions in Germany and studied 199 tree‐hole inhabiting arthropod communities. 4.We found that increasing forest management intensity indeed significantly reduced arthropod abundance and richness in water‐filled tree‐holes. The most important indirect effects of management intensity on tree‐hole community structure were the reduced amounts of detritus for the tree‐hole inhabiting organisms and changed water chemistry at the tree‐hole scale, both of which seem to act as a habitat filter. Although habitat availability at the forest stand scale decreased with increasing management intensity, this unexpectedly increased local arthropod abundance in individual tree‐holes. However, regional species richness in tree‐holes significantly decreased with increasing management intensity, most likely due to decreased habitat diversity. We did not find that the management‐driven increase in plant diversity at the forest stand scale affected communities of individual tree‐holes, for example via resource availability for adults. 5.Our results suggest that management of temperate forests has to target a number of factors at different scales to conserve diverse arthropod communities in water‐filled tree holes. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-02T02:31:52.11505-05:0
      DOI: 10.1111/1365-2656.12437
       
  • Taxonomic and functional composition of arthropod assemblages across
           contrasting Amazonian forests
    • First page: 227
      Abstract: Arthropods represent most of global biodiversity, with the highest diversity found in tropical rainforests. Nevertheless, we have a very incomplete understanding of how tropical arthropod communities are assembled. We conducted a comprehensive mass‐sampling of arthropod communities within three major habitat types of lowland Amazonian rainforest, including terra firme clay, white‐sand, and seasonally‐flooded forests in Peru and French Guiana. We examined how taxonomic and functional composition (at the family level) differed across these habitat types in the two regions. The overall arthropod community composition exhibited strong turnover among habitats and between regions. In particular, seasonally‐flooded forest habitats of both regions comprised unique assemblages. Overall, 17.7% (26 of 147) of arthropod families showed significant preferences for a particular habitat type. We present a first reproducible arthropod functional classification among the 147 taxa based on similarity among 21 functional traits describing feeding source, major mouthparts and microhabitats inhabited by each taxon. We identified seven distinct functional groups whose relative abundance contrasted strongly across the three habitats, with sap and leaf feeders showing higher abundances in terra firme clay forest. Our novel arthropod functional classification provides an important complement to link these contrasting patterns of composition to differences in forest functioning across geographic and environmental gradients. This study underlines that both environment and biogeographical processes are responsible for driving arthropod taxonomic composition while environmental filtering is the main driver of the variance in functional composition. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-08T04:47:49.109916-05:
      DOI: 10.1111/1365-2656.12445
       
  • Patterns and predictors of β‐diversity in the fragmented
           Brazilian Atlantic forest: A multiscale analysis of forest specialist and
           generalist birds
    • First page: 240
      Abstract: 1.Biodiversity maintenance in human‐altered landscapes (HALs) depends on the species turnover among localities, but the patterns and determinants of β‐diversity in HALs are poorly known. In fact, declines, increases, and neutral shifts in β‐diversity have all been documented, depending on the landscape, ecological group and spatial scale of analysis. 2.We shed some light on this controversy by assessing the patterns and predictors of bird β‐diversity across multiple spatial scales considering forest specialist and habitat generalist bird assemblages. 3.We surveyed birds from 144 point counts in 36 different forest sites across two landscapes with different amount of forest cover in the Brazilian Atlantic forest. We analysed β‐diversity among points, among sites, and between landscapes with multiplicative diversity partitioning of Hill numbers. We tested whether β‐diversity among points was related to within‐site variations in vegetation structure, and if β‐diversity among sites was related to site location and/or to differences among sites in vegetation structure and landscape composition (i.e. percent forest and pasture cover surrounding each site). 4.β‐diversity between landscapes was lower than among sites and among points in both bird assemblages. In forest specialist birds, the landscape with less forest cover showed the highest β‐diversity among sites (bird differentiation among sites), but generalist birds showed the opposite pattern. At the local scale, however, the less forested landscape showed the lowest β‐diversity among points (bird homogenisation within sites), independently of the bird assemblage. β‐diversity among points was weakly related to vegetation structure, but higher β‐diversity values were recorded among sites that were more isolated from each other, and among sites with higher differences in landscape composition, particularly in the less forested landscape. 5.Our findings indicate that patterns of bird β‐diversity vary across scales and are strongly related to landscape composition. Bird assemblages are shaped by both environmental filtering and dispersal limitation, particularly in less forested landscapes. Conservation and management strategies should therefore prevent deforestation in this biodiversity hotspot. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-24T02:19:18.114894-05:
      DOI: 10.1111/1365-2656.12448
       
  • Resource specialists lead local insect community turnover associated with
           temperature – analysis of an 18‐year full‐seasonal
           record of moths and beetles
    • First page: 251
      Abstract: Insect responses to recent climate change are well documented, but the role of resource specialization in determining species vulnerability remains poorly understood. Uncovering local ecological effects of temperature change with high‐quality, standardized data provides an important first opportunity for predictions about responses of resource specialists, and long‐term time series are essential in revealing these responses. Here, we investigate temperature‐related changes in local insect communities, using a sampling site with more than a quarter‐million records from two decades (1992–2009) of full‐season, quantitative light trapping of 1543 species of moths and beetles. We investigated annual as well as long‐term changes in fauna composition, abundance and phenology in a climate‐related context using species temperature affinities and local temperature data. Finally, we explored these local changes in the context of dietary specialization. Across both moths and beetles, temperature affinity of specialists increased through net gain of hot‐dwelling species and net loss of cold‐dwelling species. The climate‐related composition of generalists remained constant over time. We observed an increase in species richness of both groups. Furthermore, we observed divergent phenological responses between cold‐ and hot‐dwelling species, advancing and delaying their relative abundance, respectively. Phenological advances were particularly pronounced in cold‐adapted specialists. Our results suggest an important role of resource specialization in explaining the compositional and phenological responses of insect communities to local temperature increases. We propose that resource specialists in particular are affected by local temperature increase, leading to the distinct temperature‐mediated turnover seen for this group. We suggest that the observed increase in species number could have been facilitated by dissimilar utilization of an expanded growing season by cold‐ and hot‐adapted species, as indicated by their oppositely directed phenological responses. An especially pronounced advancement of cold‐adapted specialists suggests that such phenological advances might help minimize further temperature‐induced loss of resource specialists. Although limited to a single study site, our results suggest several local changes in the insect fauna in concordance with expected change of larger‐scale temperature increases. Long‐term insect light trapping shows that temperature affinity of diet specialists increased through net gain of hot‐dwelling species and net loss of cold‐dwelling species. Persistence of cold‐dwelling species may have been facilitated by dissimilar phenological response of hot and cold‐dwelling species to an expanded growing season. Horse‐chestnut leaf miner (Cameraria ohridella) and acorn weevil (Curculio glandium) are examples of gained hot‐dwelling specialists. Photo credit: Jens Kirkeby (above) and Klaus Bek Nielsen.
      PubDate: 2015-11-02T00:57:32.65307-05:0
      DOI: 10.1111/1365-2656.12452
       
  • Within‐ and trans‐generational effects of herbivores and
           detritivores on plant performance and reproduction
    • First page: 283
      Abstract: 1.Mutualistic and antagonistic aboveground and belowground species have the potential to be involved in strong interactions that can either weaken or strengthen their individual impacts on plants. Their impacts can also have delayed effects on a plant's progeny by altering offspring traits and survival. Few studies have explored the effect of herbivore and detritivore interactions with parent plants on offspring vital life‐cycle processes, such as seedling emergence rate, seedling establishment, and offspring survival. 2.In the field, I experimentally studied the combined effects of floral herbivores, root herbivores, and detritivores on plant growth and reproduction of Moricandia moricandioides (Brassicaceae). In particular, I analysed the trans‐generational effects of herbivores and detritivores on seed and juvenile production as well as on vital life‐cycle processes (i.e. seedling emergence rates, survival). 3.Floral herbivores strongly reduced the number of flowers, fruits, seeds, and juveniles. Detritivores had an impact on plant success by increasing seed quality (% N and N:C ratio), although the effect was altered by the presence of floral and root herbivores. 4.I found maternal effects (trans‐generational effects) of floral herbivores, root herbivores, and detritivores. Floral herbivores reduced seedling emergence and establishment. Floral and root herbivores in combination reduced seedling emergence timing, but the effect was counteracted by detritivores. Detritivores also reduced the negative effect of floral herbivores on offspring mortality rate. 5.This study shows that the impact of aboveground and belowground organisms on M. moricandioides plants go beyond seed production and were evident in the probability of establishment and survival of the following generation. Trans‐generational effects were induced by all three groups of interacting organisms and the net consequences for plant offspring depended on the organisms interacting with the plant. This article is protected by copyright. All rights reserved.
      PubDate: 2015-10-03T07:41:34.549976-05:
      DOI: 10.1111/1365-2656.12453
       
  • Immunosenescence and the ability to survive bacterial infection in the red
           flour beetle tribolium castaneum
    • Authors: Imroze Khan; Arun Prakash, Deepa Agashe
      First page: 291
      Abstract: 1.In most animals, ageing is associated with a decline in immune function (immune senescence). However, different components of the immune system seem to age differentially, and many studies do not measure the ultimate fitness consequences of immune function after infection. Previous work shows that immune function may be traded off with other fitness components such as reproduction. It is possible that age alters the nature of these trade‐offs, particularly in conjunction with factors such as gender and mating that can also affect investment in immune function. 2.We tested the impact of age, sex and mating on post‐infection survivorship in Tribolium castaneum flour beetles, as well as the components of baseline constitutive innate immunity and external (secreted) immune function in uninfected individuals. We also tested whether the reproductive ability of uninfected females is traded off with immune function (baseline innate and external immunity) and post‐infection survivorship across age groups. 3.We found that age, sex and mating significantly affected immune components and infection outcome, although the magnitude and nature of the impact varied in each case. We found that older beetles were more susceptible to infection by the pathogen Bacillus thuringiensis even though major components of the constitutive innate immune defence (antibacterial and phenoloxidase activity) remained unchanged or improved with age. Thus, these aspects of innate immunity cannot explain the observed decline in post‐infection survival of older beetles. We did not find trade‐offs between the reproductive ability of uninfected females and their immune function. In contrast to innate immunity, external immunity showed an overall decline with age but was also affected by sex and mating. Finally, we show that bacterial infection alters external immunity via complex interactions between age, sex and mating status. 4.Our work uncovers novel interactions between age, sex and mating that can determine the evolution and outcome of immunosenescence by affecting the time course of relative investment in different immune and fitness components. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-14T06:08:24.600543-05:
      DOI: 10.1111/1365-2656.12433
       
 
 
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