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ZOOLOGY (134 journals)                     

Showing 1 - 0 of 0 Journals sorted alphabetically
Acta Herpetologica     Open Access   (Followers: 4)
Acta Theriologica     Full-text available via subscription   (Followers: 6)
Acta Zoologica     Hybrid Journal   (Followers: 4)
Acta Zoologica Cracoviensia     Free   (Followers: 2)
Acta zoológica mexicana     Open Access  
Advances in Zoology and Botany     Open Access  
African Invertebrates     Open Access  
African Journal of Herpetology     Full-text available via subscription   (Followers: 1)
African Journal of Wildlife Research     Full-text available via subscription   (Followers: 1)
African Zoology     Hybrid Journal   (Followers: 5)
American Journal of Zoological Research     Open Access  
Animal Behaviour     Hybrid Journal   (Followers: 111)
Animal Biology     Hybrid Journal   (Followers: 7)
Animal Biology & Animal Husbandry     Open Access   (Followers: 4)
Animal Biotelemetry     Open Access   (Followers: 1)
Animal Genetics     Hybrid Journal   (Followers: 8)
Animal Migration     Open Access   (Followers: 1)
Animal Studies Journal     Open Access   (Followers: 4)
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: 6)
Applied Animal Behaviour Science     Hybrid Journal   (Followers: 17)
Applied Entomology and Zoology     Partially Free   (Followers: 2)
Aquatic Mammals     Full-text available via subscription   (Followers: 8)
Aquatic Sciences     Hybrid Journal   (Followers: 12)
Arquivos de Ciências Veterinárias e Zoologia da UNIPAR     Open Access  
Arthropod Management Tests     Hybrid Journal   (Followers: 2)
Asian Journal of Animal and Veterinary Advances     Open Access   (Followers: 7)
Australian Journal of Zoology     Hybrid Journal  
Bangladesh Journal of Zoology     Open Access  
Bioacoustics : The International Journal of Animal Sound and its Recording     Partially Free   (Followers: 2)
Biodiversidade     Open Access  
Bird Study     Full-text available via subscription   (Followers: 24)
Brazilian Journal of Veterinary Research and Animal Science     Open Access   (Followers: 8)
British Birds     Full-text available via subscription   (Followers: 24)
Bulletin of the Museum of Comparative Zoology     Full-text available via subscription   (Followers: 2)
Canadian Journal of Animal Science     Full-text available via subscription   (Followers: 3)
Canadian Journal of Zoology     Full-text available via subscription   (Followers: 14)
Contributions to Zoology     Open Access   (Followers: 3)
Current Zoology     Full-text available via subscription  
Der Zoologische Garten     Full-text available via subscription   (Followers: 2)
Ecology of Freshwater Fish     Hybrid Journal   (Followers: 18)
European Journal of Taxonomy     Open Access   (Followers: 3)
Euscorpius     Open Access  
EvoDevo     Open Access   (Followers: 2)
Fish and Fisheries     Hybrid Journal   (Followers: 28)
Frontiers in Zoology     Open Access   (Followers: 7)
Graellsia     Open Access  
Herpetology Notes     Open Access   (Followers: 1)
Hystrix, the Italian Journal of Mammalogy     Open Access  
i-Perception     Open Access   (Followers: 2)
Iheringia. Série Zoologia     Open Access   (Followers: 1)
In Vitro Cellular & Developmental Biology - Animal     Hybrid Journal   (Followers: 1)
Integrative Zoology     Hybrid Journal  
International Journal of Odonatology     Hybrid Journal   (Followers: 1)
International Journal of Zoological Research     Open Access   (Followers: 1)
International Journal of Zoology     Open Access   (Followers: 2)
International Studies on Sparrows     Open Access  
International Zoo Yearbook     Hybrid Journal   (Followers: 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: 55)
Journal of Animal Physiology and Animal Nutrition     Hybrid Journal   (Followers: 5)
Journal of Apicultural Science     Open Access   (Followers: 2)
Journal of Applied Animal Research     Hybrid Journal   (Followers: 2)
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: 2)
Journal of Freshwater Ecology     Hybrid Journal   (Followers: 15)
Journal of Herpetology     Full-text available via subscription   (Followers: 7)
Journal of Morphology     Hybrid Journal   (Followers: 2)
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: 32)
Journal of Zoo and Aquarium Research     Open Access   (Followers: 3)
Journal of Zoological Systematics and Evolutionary Research     Hybrid Journal   (Followers: 3)
Journal of Zoology     Hybrid Journal   (Followers: 19)
Laboratory Animals     Hybrid Journal   (Followers: 13)
Mammalia     Hybrid Journal   (Followers: 6)
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  
New Zealand Journal of Zoology     Hybrid Journal   (Followers: 3)
Papéis Avulsos de Zoologia     Open Access  
Parasite     Open Access   (Followers: 4)
Physiological and Biochemical Zoology     Full-text available via subscription   (Followers: 6)
Polish Journal of Entomology     Open Access   (Followers: 4)
Primate Biology     Open Access  
Protist Genomics     Open Access  
Redia : Journal of Zoology     Open Access  
Remote Sensing in Ecology and Conservation     Open Access   (Followers: 13)
Research in Zoology     Open Access   (Followers: 2)
Revista Brasileira de Reprodução Animal     Open Access  
Revista Brasileira de Zoologia     Open Access  
Revista de Biología Marina y Oceanografía     Open Access  
Revista de Educação Continuada em Medicina Veterinária e Zootecnia     Open Access  
Revista de Zoologia     Open Access   (Followers: 1)
Russian Journal of Herpetology     Full-text available via subscription   (Followers: 1)
Scientific Journal of Animal Science     Open Access   (Followers: 3)
Scientific Journal of Zoology     Open Access   (Followers: 2)
SHILAP Revista de Lepidopterologia     Open Access   (Followers: 2)
Skeletal Muscle     Open Access   (Followers: 1)
South American Journal of Herpetology     Full-text available via subscription   (Followers: 3)
Sri Lanka Journal of Aquatic Sciences     Open Access   (Followers: 1)
Travaux du Muséum National d’Histoire Naturelle “Grigore Antipa”     Open Access  
Tropical Zoology     Partially Free   (Followers: 1)
Turkish Journal of Zoology     Open Access  
University Journal of Zoology, Rajshahi University     Open Access  
Veterinária e Zootecnia     Open Access  
Waterbirds     Full-text available via subscription   (Followers: 9)
Wildlife Society Bulletin     Hybrid Journal   (Followers: 8)
World Rabbit Science     Full-text available via subscription  
Zoo Biology     Hybrid Journal   (Followers: 7)
ZooKeys     Open Access   (Followers: 4)
Zoologia (Curitiba)     Open Access   (Followers: 1)
Zoologica Poloniae : The Journal of Polish Zoological Society     Open Access   (Followers: 1)
Zoologica Scripta     Hybrid Journal   (Followers: 2)
Zoological Journal of the Linnean Society     Hybrid Journal   (Followers: 7)
Zoological Letters     Open Access  
Zoological Science     Full-text available via subscription   (Followers: 2)
Zoological Studies     Open Access   (Followers: 1)
Zoologische Mededelingen     Open Access  
Zoologischer Anzeiger - A Journal of Comparative Zoology     Hybrid Journal  
Zoologist (The)     Full-text available via subscription  
Zoology     Hybrid Journal   (Followers: 5)
Zoology and Ecology     Hybrid Journal   (Followers: 4)
Zoomorphology     Hybrid Journal   (Followers: 1)
Zoosystematics and Evolution - Mitteilungen Aus Dem Museum Fur Naturkunde Zu Berlin     Open Access   (Followers: 1)
Zootecnia     Open Access  


Journal Cover Journal of Animal Ecology
  [SJR: 3.359]   [H-I: 119]   [55 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  [1609 journals]
  • Injecting Epidemiology into Population Viability Analysis: Avian Cholera
           Transmission Dynamics at an Arctic Seabird Colony
    • Authors: Samuel A. Iverson; H. Grant Gilchrist, Catherine Soos, Isabel I. Buttler, N. Jane Harms, Mark R. Forbes
      Abstract: 1.Infectious diseases have the potential to spread rapidly and cause high mortality within populations of immunologically naïve hosts. The recent appearance of avian cholera, a highly virulent disease of birds caused by the bacterium Pasteurella multocida, at remote Arctic seabird colonies is an emerging conservation concern. 2.Determining disease risk to population viability requires a quantitative understanding of transmission potential and the factors that regulate epidemic persistence. Estimates of the basic (R0) and real‐time (Rt) reproductive number are critical in this regard – enumerating the number of secondary infections caused by each primary infection in a newly invaded host population and the decline in transmission rate as susceptible individuals are removed via mortality or immunized recovery. 3.Here, we use data collected at a closely monitored common eider (Somateria mollissima) breeding colony located in the Canadian Arctic to examine transmission and host population dynamics. Specifically, we infer epidemic curves from daily mortality observations and use a likelihood‐based procedure to estimate changes in the reproductive number over a series of annual outbreaks. These data are interpreted in relation to concurrent changes in host numbers to assess local extinction risk. 4.Consistent with expectations for a novel pathogen invasion, case incidence increased exponentially during the initial wave of exposure (R0 = 2.5; generation time = 6.5 d ± 1.1 SD). Disease conditions gradually abated, but only after several years of smouldering infection (Rt ≈ 1). In total, 6194 eider deaths were recorded during outbreaks spanning eight consecutive breeding seasons. Breeding pair abundance declined by 56% from the pre‐outbreak peak; however, a robust population of >4000 pairs remained intact upon epidemic fade‐out. Overall, outbreak patterns were consistent with herd immunity acting as a mitigating factor governing in the extent and duration of mortality. 5.Disease mortality is frequently modelled as a form of stochastic catastrophe in wildlife population assessments, whereas our approach gives shape to the functional response between transmission and host population dynamics. We conclude that increased emphasis on integrating epidemiological and population processes is essential to predicting the conservation impact of emerging infectious diseases in wildlife. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-20T10:45:26.833225-05:
      DOI: 10.1111/1365-2656.12585
  • How individual Montagu's Harriers cope with Moreau's Paradox during the
           Sahelian winter
    • Authors: Almut Ellinor Schlaich; Raymond H. G. Klaassen, Willem Bouten, Vincent Bretagnolle, Ben Johannes Koks, Alexandre Villers, Christiaan Both
      Abstract: Hundreds of millions of Afro‐Palaearctic migrants winter in the Sahel, a semi‐arid belt south of the Sahara desert, where they experience deteriorating ecological conditions during their overwintering stay and have to prepare for spring migration when conditions are worst. This well‐known phenomenon was first described by R.E. Moreau and is known ever since as Moreau's Paradox. However, empirical evidence of the deteriorating seasonal ecological conditions is limited and little is known on how birds respond. Montagu's Harriers Circus pygargus spend 6 months of the year in their wintering areas in the Sahel. Within the wintering season, birds move gradually to the south, visiting several distinct sites to which they are site‐faithful in consecutive years. At the last wintering site, birds find themselves at the southern edge of the Sahelian zone and have no other options than facing deteriorating conditions. We tracked 36 Montagu's Harriers with GPS trackers to study their habitat use and behaviour during winter and collected data on the abundance of their main prey, grasshoppers, in Senegal. Since grasshopper abundance was positively related to vegetation greenness (measured as normalized difference vegetation index, NDVI), we used NDVI values as a proxy for prey abundance in areas where no field data were collected. Prey abundance (grasshopper counts and vegetation greenness) at wintering sites of Montagu's Harriers decreased during the wintering period. Montagu's Harriers responded to decreasing food availability by increasing their flight time during the second half of the winter. Individuals increased flight time more in areas with stronger declines in NDVI values, suggesting that lower food abundance required more intense foraging to achieve energy requirements. The apparent consequence was that Montagu's Harriers departed later in spring when their final wintering site had lower NDVI values and presumably lower food abundance and consequently arrived later at their breeding site. Our results confirmed the suggestions Moreau made 40 years ago: the late wintering period might be a bottleneck during the annual cycle with possible carry‐over effects to the breeding season. Ongoing climate change with less rainfall in the Sahel region paired with increased human pressure on natural and agricultural habitats resulting in degradation and desertification is likely to make this period more demanding, which may negatively impact populations of migratory birds using the Sahel. Migrant birds wintering in the Sahel need to prepare for spring migration in dry conditions. GPS tracking of Montagu's Harriers shows that individuals increase their foraging effort in response to decreasing food availability. Individuals departed later from drier areas, suggesting carry‐over effects of winter to breeding.
      PubDate: 2016-09-19T00:00:02.094751-05:
      DOI: 10.1111/1365-2656.12583
  • Modeling effects of nonbreeders on population growth estimates
    • Authors: Aline M. Lee; Jane M. Reid, Steven R. Beissinger
      Abstract: 1.Adult individuals that do not breed in a given year occur in a wide range of natural populations. However, such nonbreeders are often ignored in theoretical and empirical population studies, limiting our knowledge of how nonbreeders affect realized and estimated population dynamics and potentially impeding projection of deterministic and stochastic population growth rates. 2.We present and analyze a general modeling framework for systems where breeders and nonbreeders differ in key demographic rates, incorporating different forms of nonbreeding, different life histories, and frequency‐dependent effects of nonbreeders on demographic rates of breeders. 3.Comparisons of estimates of deterministic population growth rate, λ, and demographic variance, σ2d, from models with and without distinct nonbreeder classes show that models that do not explicitly incorporate nonbreeders give upwardly biased estimates of σ2d, particularly when the equilibrium ratio of nonbreeders to breeders, N*nb/N*b, is high. Estimates of λ from empirical observations of breeders only are substantially inflated when individuals frequently re‐enter the breeding population after periods of nonbreeding. 4.Sensitivity analyses of diverse parameterizations of our model framework, with and without negative frequency‐dependent effects of nonbreeders on breeder demographic rates, show how changes in demographic rates of breeders versus nonbreeders differentially affect λ. In particular, λ is most sensitive to nonbreeder parameters in long‐lived species, when N*nb/N*b > 0, and when individuals are unlikely to breed at several consecutive time steps. 5.Our results demonstrate that failing to account for nonbreeders in population studies can obscure low population growth rates that should cause management concern. Quantifying the size and demography of the nonbreeding section of populations and modeling appropriate demographic structuring is therefore essential to evaluate nonbreeders’ influence on deterministic and stochastic population dynamics. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-14T04:50:57.949622-05:
      DOI: 10.1111/1365-2656.12592
  • Intra‐specific competition, not predation, drives lizard tail loss
           on islands
    • Authors: Yuval Itescu; Rachel Schwarz, Shai Meiri, Panayiotis Pafilis
      Abstract: Tail autotomy is mainly considered an anti‐predator mechanism. Theory suggests predation pressure relaxes on islands, subsequently reducing autotomy rates. Intra‐specific aggression, which may also cause tail loss, probably intensifies on islands due to the higher abundance. We studied whether tail autotomy is mostly affected by predation pressure or by intra‐specific competition. We further studied whether predator abundance or predator richness is more important in this context. To test our predictions we examined multiple populations of two gecko species: Kotschy's gecko (Mediodactylus kotschyi; mainland and 41 islands) and the Mediterranean house gecko (Hemidactylus turcicus; mainland and 17 islands), and estimated their abundances together with five indices of predation. In both species autotomy rates are higher on islands and decline with most predation indices, in contrast with common wisdom, and increase with gecko abundance. In M. kotschyi tail loss rates are higher on predator and viper‐free islands, but increase with viper abundance.  We suggest that autotomy is not simply, or maybe even mainly, an anti‐predatory mechanism. Rather, such defense mechanisms are a response to complex direct and indirect biotic interactions and perhaps, in the case of tail autotomy in insular populations, chiefly to intra‐specific aggression. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-14T02:10:31.070689-05:
      DOI: 10.1111/1365-2656.12591
  • Cascading effects of defaunation on the coexistence of two specialized
           insect seed predators
    • Abstract: Identification of the mechanisms enabling stable coexistence of species with similar resource requirements is a central challenge in ecology. Such coexistence can be facilitated by species at higher trophic levels through complex multi‐trophic interactions, a mechanism that could be compromised by ongoing defaunation. We investigated cascading effects of defaunation on Pachymerus cardo and Speciomerus giganteus, the specialized insect seed predators of the Neotropical palm Attalea butyracea, testing the hypothesis that vertebrate frugivores and granivores facilitate their coexistence. Lab experiments showed that the two seed parasitoid species differed strongly in their reproductive ecology. Pachymerus produced many small eggs that it deposited exclusively on the fruit exocarp (exterior). Speciomerus produced few large eggs that it deposited exclusively on the endocarp, which is normally exposed only after a vertebrate handles the fruit. When eggs of the two species were deposited on the same fruit, Pachymerus triumphed only when it had a long head start, and the loser always succumbed to intraguild predation. We collected field data on the fates of 6569 Attalea seeds across sites in central Panama with contrasting degrees of defaunation and wide variation in the abundance of vertebrate frugivores and granivores. Speciomerus dominated where vertebrate communities were intact, whereas Pachymerus dominated in defaunated sites. Variation in the relative abundance of Speciomerus across all 84 sampling sites was strongly positively related with the proportion of seeds attacked by rodents, an indicator of local vertebrate abundance. Synthesis: We show that two species of insect seed predators relying on the same host plant species are niche differentiated in their reproductive strategies such that one species has the advantage when fruits are handled promptly by vertebrates and the other when they aren't. Defaunation disrupts this mediating influence of vertebrates and strongly favors one species at the expense of the other, providing a case study of the cascading effects of defaunation and its potential to disrupt coexistence of non‐target species, including the hyperdiverse phytophagous insects of tropical forests. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-09T11:01:40.388212-05:
      DOI: 10.1111/1365-2656.12590
  • Masculinized females produce heavier offspring in a group living rodent
    • Abstract: Alternative morphotypes have been reported less frequently in females than in males. An exception to this rule is the gradient of phenotypical masculinization reported in some female mammals, in which feminized and masculinized females represent two opposite ends along this gradient. These phenotypical differences originate during prenatal development as the consequence of maternal effects. Feminized and masculinized females differ in several traits, including morphological, physiological, behavioral, and reproductive traits. Differences previously reported in reproductive traits between feminized and masculinized females come mostly from mechanistic studies performed in the laboratory, and not necessarily on social species. As a result, it is unclear to what extent these reported differences between female alternative morphotypes materialize in wild, natural populations. We quantified the effect of female alternative morphotype on female reproductive traits in a natural population of Octodon degus, a highly social rodent. We assessed female alternative morphotype through a continuous gradient of anogenital distance. Thus, feminized females were close to the short end of anogenital distance, while masculinized females were close to the long end of this gradient. We also tested the hypothesis that the social environment interacts with female morphotype to influence female reproductive traits. In female degus, only body weight affected litter size, where heavier females weaned more offspring. Masculinized females delivered male‐biased litters and weaned heavier offspring. Lastly, masculinized females gave birth later in the breeding season compared to feminized females. Contrary to previous claims, our findings do not support that masculinized females are less fertile than feminized females. Moreover, masculinized females produced heavier, potentially higher quality offspring compared with feminized females. This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-02T11:50:22.966713-05:
      DOI: 10.1111/1365-2656.12588
  • Carry‐over effects on the annual cycle of a migratory seabird: an
           experimental study
    • Authors: Annette L. Fayet; Robin Freeman, Akiko Shoji, Holly L. Kirk, Oliver Padget, Chris M. Perrins, Tim Guilford
      Abstract: Long‐lived migratory animals must balance the cost of current reproduction with their own condition ahead of a challenging migration and future reproduction. In these species, carry‐over effects, which occur when events in one season affect the outcome of the subsequent season, may be particularly exacerbated. However, how carry‐over effects influence future breeding outcomes and whether (and how) they also affect behaviour during migration and wintering is unclear. Here we investigate carry‐over effects induced by a controlled, bidirectional manipulation of the duration of reproductive effort on the migratory, wintering and subsequent breeding behaviour of a long‐lived migratory seabird, the Manx shearwater Puffinus puffinus. By cross‐fostering chicks of different age between nests, we successfully prolonged or shortened by ∼25% the chick‐rearing period of 42 breeding pairs. We tracked the adults with geolocators over the subsequent year and combined migration route data with at‐sea activity budgets obtained from high‐resolution saltwater‐immersion data. Migratory behaviour was also recorded during non‐experimental years (the year before and/or two years after manipulation) for a subset of birds, allowing comparison between experimental and non‐experimental years within treatment groups. All birds cared for chicks until normal fledging age, resulting in birds with a longer breeding period delaying their departure on migration; however, birds that finished breeding earlier did not start migrating earlier. Increased reproductive effort resulted in less time spent at the wintering grounds, a reduction in time spent resting daily and a delayed start of breeding with lighter eggs and chicks and lower breeding success the following breeding season. Conversely, reduced reproductive effort resulted in more time resting and less time foraging during the winter, but a similar breeding phenology and success compared with control birds the following year, suggesting that ‘positive’ carry‐over effects may also occur but perhaps have a less long‐lasting impact than those incurred from increased reproductive effort. Our results shed light on how carry‐over effects can develop and modify an adult animal's behaviour year‐round and reveal how a complex interaction between current and future reproductive fitness, individual condition and external constraints can influence life‐history decisions. Increasing or decreasing reproductive effort in migratory birds in a controlled experiment results in oppositely directed carry‐over effects, affecting migratory and wintering behaviour, and future breeding performance. This study helps understand how carry‐over effects develop and affect the annual cycle of long‐lived migratory animals, a central question in life‐history theory.
      PubDate: 2016-08-31T00:00:04.521162-05:
      DOI: 10.1111/1365-2656.12580
  • Co‐infections and environmental conditions drive the distributions of
           blood parasites in wild birds
    • Authors: Nicholas J. Clark; Konstans Wells, Dimitar Dimitrov, Sonya M. Clegg
      Abstract: Experimental work increasingly suggests that non‐random pathogen associations can affect the spread or severity of disease. Yet due to difficulties distinguishing and interpreting co‐infections, evidence for the presence and directionality of pathogen co‐occurrences in wildlife is rudimentary. We provide empirical evidence for pathogen co‐occurrences by analysing infection matrices for avian malaria (Haemoproteus and Plasmodium spp.) and parasitic filarial nematodes (microfilariae) in wild birds (New Caledonian Zosterops spp.). Using visual and genus‐specific molecular parasite screening, we identified high levels of co‐infections that would have been missed using PCR alone. Avian malaria lineages were assigned to species level using morphological descriptions. We estimated parasite co‐occurrence probabilities, while accounting for environmental predictors, in a hierarchical multivariate logistic regression. Co‐infections occurred in 36% of infected birds. We identified both positively and negatively correlated parasite co‐occurrence probabilities when accounting for host, habitat and island effects. Two of three pairwise avian malaria co‐occurrences were strongly negative, despite each malaria parasite occurring across all islands and habitats. Birds with microfilariae had elevated heterophil to lymphocyte ratios and were all co‐infected with avian malaria, consistent with evidence that host immune modulation by parasitic nematodes facilitates malaria co‐infections. Importantly, co‐occurrence patterns with microfilariae varied in direction among avian malaria species; two malaria parasites correlated positively but a third correlated negatively with microfilariae. We show that wildlife co‐infections are frequent, possibly affecting infection rates through competition or facilitation. We argue that combining multiple diagnostic screening methods with multivariate logistic regression offers a platform to disentangle impacts of environmental factors and parasite co‐occurrences on wildlife disease. Parasite competition and facilitation are expected to occur across many host systems, yet evidence from wildlife is limited and strongly biased towards mammal hosts. Using hierarchical multivariate modelling, the authors show that interspecific parasite interactions are common and may be important drivers of blood parasite distributions in wild avian hosts.
      PubDate: 2016-08-26T03:15:30.170192-05:
      DOI: 10.1111/1365-2656.12578
  • Let's stay together' Intrinsic and extrinsic factors involved in pair
           bond dissolution in a recolonizing wolf population
    • Abstract: 1.For socially monogamous species, breeder bond dissolution has important consequences for population dynamics, but the extent to which extrinsic or intrinsic population factors causes pair dissolution remain poorly understood, especially among carnivores. 2.Using an extensive life history dataset, a survival analysis and competing risks framework, we examined the fate of 153 different wolf (Canis lupus) pairs in the recolonizing Scandinavian wolf population, during 14 winters of snow‐tracking and DNA‐monitoring. 3.Wolf pair dissolution was generally linked to a mortality event, and was strongly affected by extrinsic (i.e., anthropogenic) causes. No divorce was observed, and among the pair dissolution where causes have been identified, death of one or both wolves was always involved. Median time from pair formation to pair dissolution was three consecutive winters (i.e., approximately 2 years). Pair dissolution was mostly human‐related, primarily caused by legal control actions (36.7%), verified poaching (9.2%), and traffic‐related causes (2.1%). Intrinsic factors, such as disease and age, accounted for only 7.7% of pair dissolutions. The remaining 44.3% of dissolution events were from unknown causes, but we argue that a large portion could be explained by an additional source of human‐caused mortality; cryptic poaching. 4.Extrinsic population factors, such as variables describing the geographical location of the pair, had a stronger effect on risk of pair dissolution compared to anthropogenic landscape characteristics. Population intrinsic factors, such as the inbreeding coefficient of the male pair member, had a negative effect on pair bond duration. The mechanism behind this result remains unknown, but might be explained by lower survival of inbred males or more complex inbreeding effects mediated by behavior. 5.Our study provides quantitative estimates of breeder bond duration in a social carnivore and highlights the effect of extrinsic (i.e., anthropogenic) and intrinsic factors (i.e., inbreeding) involved in wolf pair bond duration. Unlike the effects of intrinsic and extrinsic factors that are commonly reported on individual survival or population growth, here we provide quantitative estimates of their potential effect on the social unit of the population, the wolf pair. This article is protected by copyright. All rights reserved.
      PubDate: 2016-08-25T09:25:23.717448-05:
      DOI: 10.1111/1365-2656.12587
  • Symbionts modify interactions between insects and natural enemies in the
    • Abstract: 1.Eukaryotes commonly host communities of heritable symbiotic bacteria, many of which are not essential for their hosts’ survival and reproduction. There is laboratory evidence that these facultative symbionts can provide useful adaptations, such as increased resistance to natural enemies. However, we do not know how symbionts affect host fitness when the latter are subject to attack by a natural suite of parasites and pathogens. 2.Here we test whether two protective symbionts, Regiella insecticola and Hamiltonella defensa, increase the fitness of their host, the pea aphid (Acyrthosiphon pisum), under natural conditions. 3.We placed experimental populations of two pea aphid lines, each with and without symbionts, in five wet meadow sites to expose them to a natural assembly of enemy species. The aphids were then retrieved and mortality from parasitoids, fungal pathogens and other causes assessed. 4.We found that both Regiella and Hamiltonella reduce the proportion of aphids killed by the specific natural enemies against which they have been shown to protect in laboratory and cage experiments. However, this advantage was nullified (Hamiltonella) or reversed (Regiella) by an increase in mortality from other natural enemies and by the cost of carrying the symbiont. Symbionts therefore affect community structure by altering the relative success of different natural enemies. 5.Our results show that protective symbionts are not necessarily advantageous to their hosts, and may even behave more like parasites than mutualists. Nevertheless, bacterial symbionts may play an important role in determining food web structure and dynamics. This article is protected by copyright. All rights reserved.
      PubDate: 2016-08-25T09:21:02.75703-05:0
      DOI: 10.1111/1365-2656.12586
  • Genetic mixture of multiple source populations accelerates invasive range
    • Authors: Natalie K. Wagner; Brad M. Ochocki, Kerri M. Crawford, Aldo Compagnoni, Tom E.X. Miller
      Abstract: 1.A wealth of population‐genetic studies have documented that many successful biological invasions stem from multiple introductions from genetically distinct source populations. Yet, mechanistic understanding of whether and how genetic mixture promotes invasiveness has lagged behind documentation that such mixture commonly occurs. We conducted a laboratory experiment to test the influence of genetic mixture on the velocity of invasive range expansion. 2.The mechanistic basis for effects of genetic mixture could include evolutionary responses (mixed invasions may harbor greater genetic diversity and thus elevated evolutionary potential) and / or fitness advantages of between‐population mating (heterosis). If driven by evolution, positive effects of source population mixture should increase through time, as selection sculpts genetic variation. If driven by heterosis, effects of mixture should peak following first reproductive contact and then dissipate. 3.Using a laboratory model system (beetles spreading through artificial landscapes), we quantified the velocity of range expansion for invasions initiated with one, two, four, or six genetic sources over six generations. Our experiment was designed to test predictions corresponding to the evolutionary and heterosis mechanisms, asking whether any effects of genetic mixture occurred in early or later generations of range expansion. We also quantified demography and dispersal for each experimental treatment, since any effects of mixture should be manifest in one or both of these traits. 4.Over six generations, invasions with any amount of genetic mixture (two, four, and six sources) spread farther than single‐source invasions. Our data suggest that heterosis provided a “catapult effect”, leaving a lasting signature on range expansion even though the benefits of out‐crossing were transient. Individual‐level trait data indicated that genetic mixture had positive effects on local demography (reduced extinction risk and enhanced population growth) during the initial stages of invasion but no consistent effects on dispersal ability. 5.Our work is the first to demonstrate that genetic mixture can alter the course of spatial expansion, the stage of invasion typically associated with the greatest ecological and economic impacts. We suggest that similar effects of genetic mixture may be a common feature of biological invasions in nature, but that these effects can easily go undetected. This article is protected by copyright. All rights reserved.
      PubDate: 2016-08-08T10:22:21.413438-05:
      DOI: 10.1111/1365-2656.12567
  • Interspecific interference competition at the resource patch scale: do
           large herbivores spatially avoid elephants while accessing water?
    • Abstract: 1.Animals may anticipate and try to avoid, at some costs, physical encounters with other competitors. This may ultimately impact their foraging distribution and intake rates. Such cryptic interference competition is difficult to measure in the field and extremely little is known at the interspecific level. 2.We tested the hypothesis that smaller species avoid larger ones because of potential costs of interference competition, and hence expected them to segregate from larger competitors at the scale of a resource‐patch. We assessed fine‐scale spatial segregation patterns between three African herbivore species (zebra Equus quagga, kudu Tragelaphus strepsiceros and giraffe Giraffa camelopardalis) and a megaherbivore, the African elephant Loxodonta africana, at the scale of water resource patches in the semi‐arid ecosystem of Hwange National Park, Zimbabwe. 3.Nine waterholes were monitored every two weeks during the dry season of a drought year and observational scans of the spatial distribution of all herbivores were performed every 15 minutes. We developed a methodological approach to analyse such fine‐scale spatial data. 4.Elephants increasingly used waterholes as the dry season progressed, as did the probability of co‐occurrence and agonistic interaction with elephants for the three study species. All three species segregated from elephants at the beginning of the dry season, suggesting a spatial avoidance of elephants and the existence of costs of being close to them. However, contrarily to our expectations, herbivores did not segregate from elephants the rest of the dry season but tended to increasingly aggregate with elephants as the dry season progressed. 5.We discuss these surprising results and the existence of a trade‐off between avoidance of interspecific interference competition and other potential factors such as access to quality‐water, which may have relative associated costs that change with the time of the year. This article is protected by copyright. All rights reserved.
      PubDate: 2016-08-06T02:57:51.501293-05:
      DOI: 10.1111/1365-2656.12582
  • Nematode parasite diversity in birds: the role of host ecology, life
           history, and migration
    • Authors: T.L.F. Leung; J. Koprivnikar
      Abstract: 1.Previous studies have found that migratory birds generally have a more diverse array of pathogens such as parasites, as well as higher intensities of infection. However, it is not clear whether this is driven by the metabolic and physiological demands of migration, differential selection on host life history traits, or basic ecological differences between migratory and non‐migratory species. 2.Parasitic helminths can cause significant pathology in their hosts, and many are trophically‐transmitted such that host diet and habitat use play key roles in the acquisition of infections. Given the concurrent changes in avian habitats and migratory behaviour, it is critical to understand the degree to which host ecology influences their parasite communities. 3.We examined nematode parasite diversity in 153 species of Anseriformes (water birds) and Accipitriformes (predatory birds) in relation to their migratory behaviour, diet, habitat use, geographic distribution, and life history using previously published data. 4.Overall, migrators, host species with wide geographic distributions, and those utilizing multiple aquatic habitats had greater nematode richness (number of species), and birds with large clutches harboured more diverse nematode fauna with respect to number of superfamilies. Separate analyses for each host order found similar results related to distribution, habitat use, and migration; however, herbivorous water birds played host to a less diverse nematode community compared to those that consume some animals. 5.Birds using multiple aquatic habitats have a more diverse nematode fauna relative to primarily terrestrial species, likely because there is greater opportunity for contact with parasite infectious stages and/or consumption of infected hosts. As such, omnivorous and carnivorous birds using aquatic habitats may be more affected by environmental changes which alter their diet and range. Even though there were no overall differences in their ecology and life history compared with non‐migrators, migratory bird species still harboured a more diverse array of nematodes, suggesting that this behaviour places unique demands on these hosts and warrants further study. This article is protected by copyright. All rights reserved.
      PubDate: 2016-08-06T02:57:31.524096-05:
      DOI: 10.1111/1365-2656.12581
  • The modulating role of group stability on fitness effects of group size is
           different in females and males of a communally rearing rodent
    • Abstract: 1.Group size may influence fitness benefits and costs that emerge from cooperative and competitive interactions in social species. However, evidence from plural breeding mammals indicates that group size is insufficient to explain variation in direct fitness, implying other attributes of social groups were overlooked. 2.We studied the natural population of a social rodent during 5 years to test the hypothesis that social stability – in terms of group composition – modulates the effects of increasing number of breeding females (a proxy of communal rearing) and males on the number of offspring weaned (sired) and on the number of offspring weaned (sired) surviving to breeding age (two proxies of direct fitness). We quantified the effects of social stability (measured as changes in female or male group members between mating and the onset of lactation) on these fitness measures. 3.We used live trapping, telemetry, and DNA markers to determine social and fitness measures. 4.Social stability in degus was variable in terms of the number of changes in group composition across groups. Low stability was mostly due to mortality and emigration of group members. 5.Results supported a modulating role of social stability on the relationship between group size and the number of offspring weaned (sired). Stability in female and male group composition were both modulators of fitness to females and males. 6.The modulatory role of stability was sex‐specific, where high social stability was often fitness beneficial to the females. Instead, low social stability was fitness enhancing to the males. This article is protected by copyright. All rights reserved.
      PubDate: 2016-08-02T04:17:10.115507-05:
      DOI: 10.1111/1365-2656.12566
  • Geographic variation and trade‐offs in parasitoid virulence
    • Abstract: 1.Host‐parasitoid systems are characterised by a continuous development of new defence strategies in hosts and counter‐defence mechanisms in parasitoids. This coevolutionary arms race makes host‐parasitoid systems excellent for understanding trade‐offs in host use caused by evolutionary changes in host immune responses and parasitoid virulence. However, knowledge obtained from natural host‐parasitoid systems on such trade‐offs is still limited. 2.In this study the aim was to examine trade‐offs in parasitoid virulence in Asecodes parviclava (Hymenoptera: Eulophidae) when attacking three closely related beetles: Galerucella pusilla, G. calmariensis and G. tenella (Coleoptera: Chrysomelidae). A second aim was to examine whether geographic variation in parasitoid infectivity or host immune response could explain differences in parasitism rate between northern and southern sites. 3.More specifically, we wanted to examine whether the capacity to infect host larvae differed depending on the previous host species of the parasitoids and if such differences were connected to differences in the induction of host immune systems. This was achieved by combining controlled parasitism experiments with cytological studies of infected larvae. 4.Our results reveal that parasitism success in A. parviclava differs both depending on previous and current host species, with a higher virulence when attacking larvae of the same species as the previous host. Virulence was in general high for parasitoids from G. pusilla and low for parasitoids from G. calmariensis. At the same time, G. pusilla larvae had the strongest immune response and G. calmariensis the weakest. These observations were linked to changes in the larval hemocyte composition, showing changes in cell types important for the encapsulation process in individuals infected by more or less virulent parasitoids. 5.These findings suggest on‐going evolution in parasitoid virulence and host immune response, making the system a strong candidate for further studies on host race formation and speciation. This article is protected by copyright. All rights reserved.
      PubDate: 2016-08-01T00:00:27.408915-05:
      DOI: 10.1111/1365-2656.12579
  • Direct and indirect genetic and fine‐scale location effects on
           breeding date in song sparrows
    • Authors: Ryan R. Germain; Matthew E. Wolak, Peter Arcese, Sylvain Losdat, Jane M. Reid
      Abstract: 1.Quantifying direct and indirect genetic effects of interacting females and males on variation in jointly expressed life‐history traits is central to predicting micro‐evolutionary dynamics. However, accurately estimating sex‐specific additive genetic variances in such traits remains difficult in wild populations, especially if related individuals inhabit similar fine‐scale environments. 2.Breeding date is a key life‐history trait that responds to environmental phenology and mediates individual and population responses to environmental change. However, no studies have estimated female (direct) and male (indirect) additive genetic and inbreeding effects on breeding date, and estimated the cross‐sex genetic correlation, while simultaneously accounting for fine‐scale environmental effects of breeding locations, impeding prediction of micro‐evolutionary dynamics. 3.We fitted animal models to 38 years of song sparrow (Melospiza melodia) phenology and pedigree data to estimate sex‐specific additive genetic variances in breeding date, and the cross‐sex genetic correlation, thereby estimating total additive genetic variance while simultaneously estimating sex‐specific inbreeding depression. We further fitted three forms of spatial animal model to explicitly estimate variance in breeding date attributable to breeding location, overlap among breeding locations, and spatial autocorrelation. We thereby quantified fine‐scale location variances in breeding date and quantified the degree to which estimating such variances affected estimated additive genetic variances. 4.The non‐spatial animal model estimated non‐zero female and male additive genetic variances in breeding date (sex‐specific heritabilities: 0.07 and 0.02 respectively) and a strong, positive cross‐sex genetic correlation (0.99), creating substantial total additive genetic variance (0.18). Breeding date varied with female but not male inbreeding coefficient, revealing direct, but not indirect, inbreeding depression. All three spatial animal models estimated small location variance in breeding date, but because relatedness and breeding location were virtually uncorrelated, modelling location variance did not alter estimated additive genetic variances. 5.Our results show that sex‐specific additive genetic effects on breeding date can be strongly positively correlated, which would affect any predicted rates of micro‐evolutionary change in response to sexually‐antagonistic or congruent selection. Further, we show that inbreeding effects on breeding date can also be sex‐specific, and that genetic effects can exceed phenotypic variation stemming from fine‐scale location‐based variation within a wild population. This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-23T05:50:21.499909-05:
      DOI: 10.1111/1365-2656.12575
  • Hunting promotes sexual conflict in brown bears
    • Authors: Jacinthe Gosselin; Martin Leclerc, Andreas Zedrosser, Sam M.J.G. Steyaert, Jon E. Swenson, Fanie Pelletier
      Abstract: 1.The removal of individuals through hunting can destabilize social structure, potentially affecting population dynamics. Although previous studies have shown that hunting can indirectly reduce juvenile survival through increased sexually selected infanticide, very little is known about the spatiotemporal effects of male hunting on juvenile survival. 2.Using detailed individual monitoring of a hunted population of brown bears (Ursus arctos) in Sweden (1991‐2011), we assessed the spatiotemporal effect of male removal on cub survival. 3.We modeled cub survival before, during, and after the mating season. We used three proxies to evaluate spatial and temporal variation in male turnover; distance and timing of the closest male killed and number of males that died around a female's home range center. 4.Male removal decreased cub survival only during the mating season, as expected in seasonal breeders with sexually selected infanticide. Cub survival increased with distance to the closest male killed within the previous 1.5 years and it was lower when the closest male killed was removed 1.5 instead of 0.5 year earlier. We did not detect an effect of the number of males killed. 5.Our results support the hypothesis that social restructuring due to hunting can reduce recruitment and suggest that the distribution of the male deaths might be more important than the overall number of males that die. As the removal of individuals through hunting is typically not homogenously distributed across the landscape, spatial heterogeneity in hunting pressure may cause source‐sink dynamics, with lower recruitment in areas of high human‐induced mortality. This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-23T05:45:28.41457-05:0
      DOI: 10.1111/1365-2656.12576
  • Patterns of age‐related change in reproductive effort differ in the
           prenatal and postnatal periods in a long‐lived mammal
    • Authors: J. Terrill Paterson; Jay J. Rotella, Jennifer M. Mannas, Robert A. Garrott
      Abstract: 1.Age‐related changes in maternal reproductive allocation for long‐lived species are a key prediction from life‐history theory. 2.Theoretical and empirical work suggests allocation may increase with age due to constraint (increases with experience) or restraint (increases with age in the face of declining residual reproductive value), and may decrease among the oldest aged animals due to senescence in reproductive function. 3.Here we use a hierarchical modeling approach to investigate age‐related patterns of change in maternal reproductive effort in the Weddell seal, a long‐lived marine mammal with a protracted period of maternal care during which mothers allocate a large proportion of body mass while feeding little. 4.We find maternal allocation increases with age for young mothers during both the prenatal and postnatal periods. In contrast, older mothers demonstrate a senescent decline in prenatal allocation but allocate more of their declining resources to their offspring during the postnatal period. We also find strong evidence for the importance of individual effects in reproductive allocation among mothers: some mothers consistently produce heavier (or lighter) pups than expected. 5.Our results indicate that maternal allocation changes over a mother's reproductive lifespan and that age‐specific differences differ in notable ways in prenatal and postnatal periods. This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-23T05:45:25.165889-05:
      DOI: 10.1111/1365-2656.12577
  • Mammalian engineers drive soil microbial communities and ecosystem
           functions across a disturbance gradient
    • Abstract: 1.The effects of mammalian ecosystem engineers on soil microbial communities and ecosystem functions in terrestrial ecosystems are poorly known. Disturbance from livestock has been widely reported to reduce soil function, but disturbance by animals that forage in the soil may partially offset these negative effects of livestock, directly and/or indirectly by shifting the composition and diversity of soil microbial communities. Understanding the role of disturbance from livestock and ecosystem engineers in driving soil microbes and functions is essential for formulating sustainable ecosystem management and conservation policies. 2.We compared soil bacterial community composition and enzyme concentrations within four microsites: foraging pits of two vertebrates, the indigenous short‐beaked echidna (Tachyglossus aculeatus) and the exotic European rabbit (Oryctolagus cuniculus), and surface and subsurface soils along a gradient in grazing‐induced disturbance in an arid woodland. 3.Microbial community composition varied little across the disturbance gradient, but there were substantial differences among the four microsites. Echidna pits supported a lower relative abundance of Acidobacteria and Cyanobacteria, but a higher relative abundance of Proteobacteria than rabbit pits and surface microsites. Moreover, these microsite differences varied with disturbance. Rabbit pits had a similar profile to the subsoil or the surface soils under moderate and high, but not low disturbance. 4.Overall, echidna foraging pits had the greatest positive effect on function, assessed as mean enzyme concentrations, but rabbits had the least. The positive effects of echidna foraging on function were indirectly driven via microbial community composition. In particular, increasing activity was positively associated with increasing relative abundance of Proteobacteria, but decreasing Acidobacteria. 5.Synthesis. Our study suggests that soil disturbance by animals may offset, to some degree, the oft‐reported negative effects of grazing induced‐disturbance on soil function. Further, our results suggest that most of this effect will be derived from echidnas, with little positive effects due to rabbits. Activities that enhance the habitat for echidnas or reduce rabbit populations are likely to have a positive effect on soil function in these systems. This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-18T02:16:09.339999-05:
      DOI: 10.1111/1365-2656.12574
  • Elevation and latitude interact to drive life history variation in
           precocial birds: A comparative analysis using galliformes
    • Authors: Priya Balasubramaniam; John T. Rotenberry
      Abstract: 1.Elevational gradients provide a powerful laboratory for understanding the environmental and ecological drivers of geographic variation in avian life history strategies. Environmental variation across elevational gradients is hypothesized to select for a tradeoff of reduced fecundity (lower clutch size and/or fewer broods) for higher offspring quality (larger eggs and/or increased parental care) in higher elevation species and populations. In birds, a focus on altricial species from north‐temperate latitudes has prevented an evaluation of the generality of this tradeoff, and how it is affected by latitude and intrinsic factors (development mode). 2.We performed a comparative analysis controlling for body size and phylogenetic relationships on a global dataset of 135 galliform species to test (i) whether higher elevation precocial species have lower fecundity (smaller clutch and/or fewer broods) and invest more in offspring quality (greater egg mass) and (ii) whether latitude influences the traits involved and/or the trade‐off, and (iii) to identify ecological and environmental drivers of life history variation along elevational gradients. 3.Life history traits showed significant interaction effects across elevation and latitude: temperate higher elevation species had smaller clutches and clutch mass, larger eggs, and shorter incubation periods, whereas more tropical species had larger clutches, eggs, and clutch mass, and longer incubation periods as elevation increased. Number of broods and body mass did not vary with elevation or latitude. Latitudinal gradient in clutch size was observed only for low elevation species. 4.Significantly, an overlooked latitude‐by‐elevation interaction confounds our traditional view of clutch size variation across a tropical‐to‐temperate gradient. Across all latitudes, higher elevation species invested in offspring quality via larger eggs but support for reduced fecundity resulting from smaller clutches was found only along temperate elevational gradients; contrary to expectations, tropical high elevation species showed increased fecundity. Variation in nest predation risk could explain differences between temperate and tropical elevational gradients, but we lack a consistent mechanism to explain why predation risk should vary in this manner. Alternatively, a resource‐availability hypothesis based on physical attributes that globally differ between elevation and latitude (seasonality in day‐length and temperature) seems more plausible. This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-08T08:15:20.282084-05:
      DOI: 10.1111/1365-2656.12570
  • The ontogeny of tolerance curves: Habitat quality versus acclimation in a
           stressful environment
    • Abstract: 1.Stressful environments affect life‐history components of fitness through (i) instantaneous detrimental effects, (ii) historical (carry‐over) effects, and (iii) history‐by‐environment interactions, including acclimation effects. The relative contributions of these different responses to environmental stress are likely to change along life, but such ontogenic perspective is often overlooked in studies of tolerance curves, precluding a better understanding of the causes of costs of acclimation, and more generally of fitness in temporally fine‐grained environments. 2.We performed an experiment in the brine shrimp Artemia to disentangle these different contributions to environmental tolerance, and investigate how they unfold along life. We placed individuals from three clones of A. parthenogenetica over a range of salinities during a week, before transferring them to a (possibly) different salinity for the rest of their lives. We monitored individual survival at repeated intervals throughout life, instead of measuring survival or performance at a given point in time, as commonly done in acclimation experiments. We then designed a modified survival analysis model to estimate phase‐specific hazard rates, accounting for the fact that individuals may share the same treatment for only part of their lives. 3.Our approach allowed us to distinguish effects of salinity on (i) instantaneous mortality in each phase (habitat quality effects), (ii) mortality later in life (history effects), and (iii) their interaction. We showed clear effects of early salinity on late survival, and interactions between effects of past and current environments on survival. Importantly, analysis of the ontogenetic dynamics of the tolerance curve reveals that acclimation affects different parts of the curve at different ages. 4.Adopting a dynamical view of the ontogeny of tolerance curve should prove useful for understanding niche limits in temporally changing environments, where the full sequence of environments experienced by an individual determines its overall environmental tolerance, and how it changes throughout life. This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-08T07:55:37.020196-05:
      DOI: 10.1111/1365-2656.12572
  • Consistent scaling of population structure across landscapes despite
           intraspecific variation in movement and connectivity
    • Authors: B. E. Reichert; R. J. Fletcher, C. E. Cattau, W. M. Kitchens
      Abstract: 1.Understanding the spatial scale of population structure is fundamental to long‐standing tenets of population biology, landscape ecology, and conservation. Nonetheless, identifying such scales has been challenging because a key factor that influences scaling—movement among patches or local populations—is a multi‐causal process with substantial phenotypic and temporal variation. 2.We resolve this problem via a novel application of network modularity. When applied to movements, modularity provides a formal description of the functional aggregation of populations and identifies potentially critical scales for ecological and evolutionary dynamics. We first test for modularity using several different types of biologically relevant movements across the entire geographic range of an endangered bird, the snail kite (Rostrhamus sociabilis plumbeus). We then ask whether variation in movement based on i) age, ii) sex, and iii) time (annual, seasonal, and within‐season movements) influence spatial population structure (i.e., modularity) in snail kites. 3.We identified significant modularity in movements of snail kites based on annual and within‐season movements of adults (all adults, males only, females only) and juveniles, yet no evidence of modularity in seasonal (non‐breeding) movements. For those movements with observed modular structure, we found striking similarities in the spatial configuration of population structure, even though movement properties varied considerably among these different types of movements. 4.Our results suggest that the emergence of modularity in population networks can be robust despite movement heterogeneity and differences in patch‐based measures of connectivity. Furthermore, our comparison of the population structure and connectivity across multiple movement phases helps to identify wetland patches most critical to population connectivity at multiple spatio‐temporal scales. 5.We argue that understanding modularity in populations may provide a robust complement to existing measures of population structure and connectivity and will help to clarify the limiting roles of movement for populations. Such information is increasingly needed for interpreting population persistence and guiding effective conservation strategies with ongoing environmental change. This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-08T07:55:27.003543-05:
      DOI: 10.1111/1365-2656.12571
  • Multi‐host Bartonella parasites display covert host‐specificity even
           when transmitted by generalist vectors
    • Authors: Susan M. Withenshaw; Godefroy Devevey, Amy B. Pedersen, Andy Fenton
      Abstract: Many parasites infect multiple sympatric host species and there is a general assumption that parasite transmission between co‐occurring host species is commonplace. Such between‐species transmission could be key to parasite persistence within a disease reservoir and is consequently an emerging focus for disease control. However, while a growing body of theory indicates the potential importance of between‐species transmission for parasite persistence, conclusive empirical evidence from natural communities is lacking, and the assumption that between‐species transmission is inevitable may therefore be wrong. We investigated the occurrence of between‐species transmission in a well‐studied multi‐host parasite system. We identified the flea‐borne Bartonella parasites infecting sympatric populations of Apodemus sylvaticus (Linneaus, 1978) (wood mice) and Myodes glareolus (Schreber, 1780) (bank voles) in the UK and confirmed that several Bartonella species infect both rodent species. However, counter to previous knowledge, genetic characterisation of these parasites revealed covert host‐specificity, where each host species is associated with a distinct assemblage of genetic variants, indicating that between‐species transmission is rare. Limited between‐species transmission could result from rare encounters between one host species and the parasites infecting another and/or host‐parasite incompatibility. We investigated the occurrence of such encounter and compatibility barriers by identifying the flea species associated with each rodent host, and the Bartonella variants carried by individual fleas. We found that the majority of fleas were host‐generalists but the assemblage of Bartonella variants in fleas tended to reflect the assemblage of Bartonella variants in the host species they were collected from, thus providing evidence of encounter barriers mediated by limited between‐species flea transfer. However, we also found several fleas that were carrying variants never found in the host species from which they were collected, indicating some degree of host‐pathogen incompatibility when barriers to encounter are overcome. Overall, these findings challenge our default perceptions of multi‐host parasite persistence, as they show that despite considerable overlaps in host species ecology, separate populations of the same parasite species may circulate and persist independently in different sympatric host species. This questions our fundamental understanding of endemic transmission dynamics and the control of infection within natural reservoir communities. This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-06T02:45:46.151714-05:
      DOI: 10.1111/1365-2656.12568
  • High adult mortality in disease‐challenged frog populations
           increases vulnerability to drought
    • Authors: Ben C. Scheele; David A. Hunter, Sam C. Banks, Jennifer C. Pierson, Lee F. Skerratt, Rebecca Webb, Don A. Driscoll
      Abstract: Pathogen emergence can drive major changes in host population demography, with implications for population dynamics and sensitivity to environmental fluctuations. The amphibian disease chytridiomycosis, caused by infection with the fungal pathogen Batrachochytrium dendrobatidis (Bd), is implicated in the severe decline of over 200 amphibian species. In species that have declined but not become extinct, Bd persists and can cause substantial ongoing mortality. High rates of mortality associated with Bd may drive major changes in host demography, but this process is poorly understood. Here, we compared population age structure of Bd‐infected populations, Bd‐free populations, and museum specimens collected prior to Bd emergence for the endangered Australian frog, Litoria verreauxii alpina (alpine tree frog). We then used population simulations to investigate how pathogen‐associated demographic shifts affect the ability of populations to persist in stochastic environments. We found that Bd‐infected populations have a severely truncated age structure associated with very high rates of annual adult mortality. Near‐complete annual adult turnover in Bd‐infected populations means that individuals breed once, compared with Bd‐free populations where adults may breed across multiple years. Our simulations showed that truncated age structure erodes the capacity of populations to withstand periodic recruitment failure; a common challenge for species reproducing in uncertain environments. We document previously undescribed demographic shifts associated with a globally emerging pathogen and demonstrate how these shifts alter host ecology. Truncation of age structure associated with Bd effectively reduces host niche width, and can help explain the contraction of L. v. alpina to perennial waterbodies where the risk of drought‐induced recruitment failure is low. Reduced capacity to tolerate other sources of mortality may explain variation in decline severity among other chytridiomycosis‐challenged species and highlights the potential to mitigate disease impacts through minimising other sources of mortality. This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-06T02:40:36.951801-05:
      DOI: 10.1111/1365-2656.12569
  • Hoverfly preference for high honeydew amounts creates enemy‐free space
           for aphids colonizing novel host plants
    • Authors: Ilka Vosteen; Jonathan Gershenzon, Grit Kunert
      Abstract: The existence of an enemy‐free space can play an important role in aphid host race formation processes, but little is known about the mechanisms that create an area of low predation pressure on particular host plants. In this paper we identify a mechanism generating lower predation pressure that promotes the maintenance of the different host races of the pea aphid (Acyrthosiphon pisum) complex, a well‐studied model for ecological speciation. The pea aphid consists of at least 15 genetically distinct host races which are native to specific host plants of the legume family, but can all develop on the universal host plant Vicia faba. Previous work showed that hoverfly (Episyrphus balteatus) oviposition preferences contribute to the enemy‐free space that helps to maintain the different pea aphid host races, and that higher amounts of honeydew are more attractive to ovipositing hoverflies. Here we demonstrated that aphid honeydew is produced in large amounts when aphid reproduction rate was highest, and so is an important oviposition cue for hoverflies under field conditions. However, on less suitable host plants, where honeydew production is reduced, pea aphids enjoy lower predation rates. A reduction in enemy pressure can mitigate the performance disadvantages of aphids colonizing a novel host, and probably plays an important role in pea aphid host race formation. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-22T03:00:26.364936-05:
      DOI: 10.1111/1365-2656.12564
  • The dominant detritus‐feeding invertebrate in arctic peat soils derives
           its essential amino acids from gut symbionts
    • Abstract: Supplementation of nutrients by symbionts enables consumers to thrive on resources that might otherwise be insufficient to meet nutritional demands. Such nutritional subsidies by intracellular symbionts has been well studied; however, supplementation of de novo synthesized nutrients to hosts by extracellular gut symbionts is poorly documented, especially for generalists with relatively undifferentiated intestinal tracts. Although gut symbionts facilitate degradation of resources that would otherwise remain inaccessible to the host, such digestive actions alone cannot make up for dietary insufficiencies of macronutrients such as essential amino acids (EAA). Documenting whether gut symbionts also function as partners for symbiotic EAA supplementation is important because the question of how some detritivores are able to subsist on nutritionally insufficient diets has remained unresolved. To answer this poorly‐understood nutritional aspect of symbiont‐host interactions, we studied the enchytraeid worm, a bulk soil feeder that thrives in arctic peatlands. In a combined field and laboratory study, we employed stable isotope fingerprinting of amino acids to identify the biosynthetic origins of amino acids to bacteria, fungi and plants in enchytraeids. Enchytraeids collected from arctic peatlands derived more than 80% of their EAA from bacteria. In a controlled feeding study with the enchytraeid Enchytraeus crypticus, EAA derived almost exclusively from gut bacteria when the worms fed on higher fiber diets, whereas most of the enchytraeids’ EAA derived from dietary sources when fed on lower fiber diets. Our gene sequencing results of gut microbiota showed that the worms harbor several taxa in their gut lumen absent from their diets and substrates. Almost all gut taxa are candidates for EAA supplementation because almost all belong to clades capable of biosynthesizing EAA. Our study provides the first evidence of extensive symbiotic supplementation of EAA by microbial gut symbionts, and demonstrate that symbiotic bacteria in the gut lumen appear to function as partners for both symbiotic EAA supplementation as well as for digestion of insoluble plant fibers. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-20T10:20:27.337915-05:
      DOI: 10.1111/1365-2656.12563
  • Diet preferences as the cause of individual differences rather than the
    • Authors: Thomas Oudman; Allert I. Bijleveld, Marwa M. Kavelaars, Anne Dekinga, John Cluderay, Theunis Piersma, Jan A. Gils
      Abstract: Behavioural variation within a species is usually explained as the consequence of individual variation in physiology. However, new evidence suggests that the arrow of causality may well be in the reverse direction: behaviours such as diet preferences cause the differences in physiological and morphological traits. Recently, diet preferences were proposed to underlie consistent differences in digestive organ mass and movement patterns (patch residence times) in red knots (Calidris canutus islandica). Red knots are molluscivorous and migrant shorebirds for which the size of the muscular stomach (gizzard) is critical for the food processing rate. In this study, red knots (C. c. canutus, n = 46) were caught at Banc d'Arguin, an intertidal flat ecosystem in Mauritania, and released with radio‐tags after the measurement of gizzard mass. Using a novel tracking system (time‐of‐arrival), patch residence times were measured over a period of three weeks. Whether or not gizzard mass determined patch residence times was tested experimentally by offering 12 of the 46 tagged red knots soft diets prior to release; this reduced an individual's gizzard mass by 20–60%. To validate whether the observed range of patch residence times would be expected from individual diet preferences, we simulated patch residence times as a function of diet preferences via a simple departure rule. Consistent with previous empirical studies, patch residence times in the field were positively correlated with gizzard mass. The slope of this correlation, as well as the observed range of patch residence times, was in accordance with the simulated values. The 12 birds with reduced gizzard masses did not decrease patch residence times in response to the reduction in gizzard mass. These findings suggest that diet preferences can indeed cause the observed among‐individual variation in gizzard mass and patch residence times. We discuss how early diet experiences can have cascading effects on the individual expression of both behavioural and physiomorphic traits. This emphasizes that to understand the ecological consequences of individual differences, knowledge of the environment during development is required. Behavioural differences between animals are often explained by their physiology or morphology. The authors studied the causality between physiomorphic and behavioural differences in red knots, migratory shorebirds that feed on bivalves. They show that differences in gut size and movement patterns are likely caused by diet preferences, rather than vice versa. Photo credit: Jeroen Onrust.
      PubDate: 2016-06-16T02:45:33.960849-05:
      DOI: 10.1111/1365-2656.12549
  • Erratum
    • PubDate: 2016-06-15T07:10:24.558451-05:
      DOI: 10.1111/1365-2656.12553
  • Prey size and scramble vs. contest competition in a social spider:
           implications for population dynamics
    • Abstract: 1.There are many benefits of group living, but also substantial costs, one of which is competition for resources. How scarce food resources are distributed among different members of a population or social group—whether via scramble or contest competition— can influence not only the variance in individual fitness, but also the stability and therefore survival of the group or population. 2.Attributes of the food resources themselves, such as their size, may also influence the type of intraspecific competition that occurs, and therefore the intrinsic stability of a group or population. 3.By experimentally manipulating the size of prey fed to artificial colonies of the social spider Anelosimus eximius, we investigated whether prey size could alter the degree of scramble vs. contest competition that takes place and, thus, potentially, influence colony population dynamics. 4.We found that large prey were shared more evenly than small prey, and that individuals in poor condition were more likely to feed when prey were large than when prey were small. Additionally we show that individuals participating in prey capture are also more likely to feed on the captured prey. 5.We developed a simple mathematical model to explore the prey sizes that would be energetically worth defending, i.e. “economically defendable”. The model shows that neither very small, nor prey above a certain size is worth monopolizing, with only intermediate size prey being “economically defendable”. We therefore suggest the small and large prey in our experiment corresponds to our model's intermediate and large prey categories respectively. 6.As the size of prey captured by social spider colonies increases with colony size, our findings suggest that scramble competition may predominate in large colonies. Scramble competition, combined with the fact that prey biomass per capita declines as colonies grow beyond a certain size, would then explain why extremely large colonies of this social spider may suddenly go extinct. Our project thus illustrates the potential triple link between characteristics of the resources, individual behaviour, and population dynamics, a link rarely considered in an empirical setting. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-14T09:25:26.960416-05:
      DOI: 10.1111/1365-2656.12559
  • Energy storage and fecundity explain deviations from ecological
           stoichiometry predictions under global warming and size‐selective
    • Authors: Chao Zhang; Mieke Jansen, Luc De Meester, Robby Stoks
      Abstract: 1.A key challenge for ecologists is to predict how single and joint effects of global warming and predation risk translate from the individual level up to ecosystem functions. Recently, stoichiometric theory linked these levels through changes in body stoichiometry, predicting that both higher temperatures and predation risk induce shifts in energy storage (increases in C‐rich carbohydrates and reductions in N‐rich proteins) and body stoichiometry (increases in C:N and C:P). This promising theory, however, is rarely tested and assumes that prey will divert energy away from reproduction under predation risk, while under size‐selective predation, prey instead increase fecundity. 2.We exposed the water flea Daphnia magna to 4 °C warming and fish predation risk to test whether C‐rich carbohydrates increase and N‐rich proteins decrease and as a result C:N and C:P increase under warming and predation risk. 3.Unexpectedly, warming decreased body C:N, which was driven by reductions in C‐rich fat and sugar contents while the protein content did not change. This reflected a trade‐off where the accelerated intrinsic growth rate under warming occurred at the cost of a reduced energy storage. Warming reduced C:N less and only increased C:P and N:P in the fish‐period Daphnia. These evolved stoichiometric responses to warming were largely driven by stronger warming‐induced reductions in P than in C and N and could be explained by the better ability to deal with warming in the fish‐period Daphnia. 4.In contrast to theory predictions, body C:N decreased under predation risk due to a strong increase in the N‐rich protein content that offset the increase in C‐rich fat content. The higher investment in fecundity (more N‐rich eggs) under predation risk contributed to this stronger increase in protein content. Similarly, the lower body C:N of pre‐fish Daphnia also matched their higher fecundity. 5.Warming and predation risk independently shaped body stoichiometry, largely by changing levels of energy storage molecules. Our results highlight that two widespread patterns, the trade‐off between rapid development and energy storage and the increased investment in reproduction under size‐selective predation cause predictable deviations from current ecological stoichiometry theory. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-15T00:36:29.495401-05:
      DOI: 10.1111/1365-2656.12531
  • Beyond neutral and forbidden links: morphological matches and the assembly
           of mutualistic hawkmoth‐plant networks
    • Abstract: 1.A major challenge in evolutionary ecology is to understand how coevolutionary processes shape patterns of interactions between species at community level. Pollination of flowers with long corolla tubes by long‐tongued hawkmoths has been invoked as a showcase model of coevolution. Recently, optimal foraging models have predicted that there might be a close association between mouthparts length and the corolla depth of the visited flowers, thus favouring trait convergence and specialisation at community level. 2.Here, we assessed whether hawkmoths more frequently pollinate plants with floral tube lengths similar to their proboscis lengths (morphological match hypothesis) against abundance‐based processes (neutral hypothesis) and ecological trait mismatches constraints (forbidden links hypothesis), in structuring hawkmoth‐plant mutualistic networks from five communities in four biogeographical regions of South America. 3.We found convergence in morphological traits across the five communities and that the distribution of morphological differences between hawkmoths and plants is consistent with expectations under the morphological match hypothesis in three of the five communities. In the two remaining communities, which are ecotones between two distinct biogeographic areas, interactions are better predicted by the neutral hypothesis. 4.Our findings are consistent with the idea that diffuse coevolution drives the evolution of extremely long proboscises and flower tubes, and highlight the importance of morphological traits, beyond the forbidden links hypothesis, in structuring interactions between mutualistic partners, revealing that the role of niche‐based processes can be much more complex than previously known. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-02T02:45:04.321843-05:
      DOI: 10.1111/1365-2656.12509
  • It's only a matter of time: the altered role of subsidies in a warming
    • Authors: Eoin J. O'Gorman
      First page: 1133
      Abstract: Clockwise from left: an experimental stream reach from the study, highlighting the fences used to contain fish as the apex predator; a cutthroat trout from the experiment, the only fish species in the study streams; stomach contents from a fish, highlighting the major role of the terrestrial subsidy (mealworms) in the diet. In Focus: Sato, T., El‐Sabaawi, R.W., Campbell, K., Ohta, T. & Richardson, J.S. (2016) A test of the effects of timing of a pulsed resource subsidy on stream ecosystems. Journal of Animal Ecology, 85, 1136–1146. Cross‐ecosystem subsidies play a critical role in maintaining the structure and functioning of natural communities, especially if they are asynchronous with resource production in the recipient ecosystem. Sato et al. () use a large‐scale field experiment to show that changes in the timing of a pulsed terrestrial subsidy can alter stream dynamics from the individual to the ecosystem level. With increasing evidence that global warming will alter the timing, magnitude and frequency of allochthonous inputs, these findings make an important contribution to our understanding of how such changes will reverberate throughout ecosystems that depend on subsidies. Clockwise from left: an experimental stream reach from the study, highlighting the fences used to contain fish as the apex predator; a cutthroat trout from the experiment, the only fish species in the study streams; stomach contents from a fish, highlighting the major role of the terrestrial subsidy (mealworms) in the diet.
      PubDate: 2016-08-11T07:04:54.592899-05:
      DOI: 10.1111/1365-2656.12560
  • The effects of food‐web structure on ecosystem function exceeds
           those of precipitation
    • First page: 1147
      Abstract: Ecosystems are being stressed by climate change, but few studies have tested food web responses to changes in precipitation patterns and the consequences to ecosystem function. Fewer still have considered whether results from one geographic region can be applied to other regions, given the degree of community change over large biogeographic gradients. We assembled, in one field site, three types of macroinvertebrate communities within water‐filled bromeliads. Two represented food webs containing both a fast filter feeder‐microbial and slow detritivore energy channels found in Costa Rica and Puerto Rico, and one represented the structurally simpler food webs in French Guiana, which only contained the fast filter feeder‐microbial channel. We manipulated the amount and distribution of rain entering bromeliads, and examined how food web structure mediated ecosystem responses to changes in the quantity and temporal distribution of precipitation. Food web structure affected the survival of functional groups in general, and ecosystem functions such as decomposition and the production of fine particulate organic matter. Ecosystem processes were more affected by decreased precipitation than were the abundance of microorganisms and metazoans. In our experiments, the sensitivity of the ecosystem to precipitation change was primarily revealed in the food web dominated by the single filter feeder‐microbial channel because other top‐down and bottom‐up processes were weak or absent. Our results show stronger effects of food web structure than precipitation change per se on the functioning of bromeliad ecosystems. Consequently, we predict that ecosystem function in bromeliads throughout the Americas will be more sensitive to changes in the distribution of species, rather than to the direct effects caused by changes in precipitation. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-01T04:20:35.459175-05:
      DOI: 10.1111/1365-2656.12538
  • Predator identity influences metacommunity assembly
    • Authors: Nicole K. Johnston; Zhichao Pu, Lin Jiang
      First page: 1161
      Abstract: 1.Predation is among the most important biotic factors influencing natural communities, yet we have a rather rudimentary understanding of its role in modulating metacommunity assembly. 2.We experimentally examined the effects of two different predators (a generalist and a specialist) on metacommunity assembly, using protist microcosm metacommunities that varied in predator identity, dispersal among local communities, and the history of species colonization into local communities. 3.Generalist predation resulted in reduced α diversity and increased β diversity irrespective of dispersal, likely due to predation‐induced stochastic extinction of different prey species in different local communities. Dispersal, however, induced source‐sink dynamics in the presence of specialist predators, resulting in higher α diversity and marginally lower β diversity. 4.These results demonstrate the distinct effects of different predators on prey metacommunity assembly, emphasizing the need to explore the role of predator diet breadth in structuring metacommunities. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-14T02:40:20.629913-05:
      DOI: 10.1111/1365-2656.12551
  • Allometric and temporal scaling of movement characteristics in Galapagos
    • First page: 1171
      Abstract: 1.Understanding how individual movement scales with body size is of fundamental importance in predicting ecological relationships for diverse species. One‐dimensional movement metrics scale consistently with body size yet vary over different temporal scales. Knowing how temporal scale influences the relationship between animal body size and movement would better inform hypotheses about the efficiency of foraging behaviour, the ontogeny of energy budgets, and numerous life history trade‐offs. 2.We investigated how the temporal scaling of allometric patterns in movement vary over the course of a year, specifically during periods of motivated (directional and fast movement) and unmotivated (stationary and tortuous movement) behaviour. We focused on a recently diverged group of species that displays wide variation in movement behaviour—giant Galapagos tortoises (Chelonoidis spp.)—to test how movement metrics estimated on a monthly basis scaled with body size. 3.We used state‐space modelling to estimate seven different movement metrics of Galapagos tortoises. We used log‐log regression of the power law to evaluate allometric scaling for these movement metrics, and contrasted relationships by species and sex. 4.Allometric scaling of movement was more apparent during motivated periods of movement. During this period, allometry was revealed at multiple temporal intervals (hourly, daily, and monthly), with values observed at daily and monthly intervals corresponding most closely to the expected ¼ scaling coefficient, albeit with wide credible intervals. We further detected differences in the magnitude of scaling among taxa uncoupled from observed differences in the temporal structuring of their movement rates. 5.Our results indicate that the definition of temporal scales is fundamental to the detection of allometry of movement, and should be given more attention in movement studies. Our approach not only provides new conceptual insights into temporal attributes in one‐dimensional scaling of movement, but also generates valuable insights into the movement ecology of iconic yet poorly understood Galapagos giant tortoises. This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-21T09:55:45.909031-05:
      DOI: 10.1111/1365-2656.12561
  • Simple settlement decisions explain common dispersal patterns in
           territorial species
    • Authors: James J. Gilroy; Julie L. Lockwood
      First page: 1182
      Abstract: Dispersal is one of the least‐understood aspects of animal behaviour. For example, little is known of the mechanisms that determine how individuals express different dispersal behaviours in different circumstances. Uncovering these mechanisms is important for our understanding of spatial population dynamics. Using agent‐based simulations, we examine how simple decision rules generate individual‐level dispersal plasticity, and how this can influence population‐scale dispersal dynamics. We model a territorial, monogamous population inhabiting a completely homogeneous environment. Dispersal variability therefore emerges solely as a result of between‐individual interactions (competition, settlement, reproduction), which are governed by simple decision‐making algorithms. We show that complex dispersal dynamics, including sex biases and strong density dependence, emerge naturally from simple rule‐based behaviours. Dispersal is particularly sensitive to the inclusion of mate availability as a criterion for settlement: if neither sex evaluates mate availability, dispersal distances tend to decline at low densities, leading to a strong Allee effect from reduced pairing success. If one sex evaluates mate availability (females), Allee effects are largely avoided, but female‐biased dispersal generates increasingly male‐biased adult sex ratios at low densities. Sex biases are eliminated if both sexes evaluate mate availability, but population growth rates tend to be reduced due to survival costs and reduced pairing success. Our models suggest that simple decision mechanisms can explain several dynamic patterns that are commonly observed among territorial species. Importantly, these patterns emerge in the absence of environmental heterogeneity or between‐individual variation in dispersal phenotypes, two conditions that are often invoked to explain dispersal heterogeneity in nature. This has implications for studies seeking to examine the causes of dispersal variability in wild populations, suggesting that observed patterns could be largely driven by the social and demographic conditions experienced by sampled individuals. Further insights could be gained by examining how selection operates on decision rules in different life‐history and environmental circumstances, and how this might interact with selection on other demographic traits. Uncovering the decision‐rules used during settlement should be a priority for those wishing to understand and predict dispersal patterns in nature. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-13T07:25:40.845164-05:
      DOI: 10.1111/1365-2656.12545
  • Coupled range dynamics of brood parasites and their hosts responding to
           climate and vegetation changes
    • First page: 1191
      Abstract: As populations shift their ranges in response to global change, local species assemblages can change, setting the stage for new ecological interactions, community equilibria, and evolutionary responses. Here we focus on the range dynamics of four avian brood parasite species and their hosts in southern Africa, in a context of bush encroachment (increase in woody vegetation density in places previously occupied by savanna‐grassland mosaics) favouring some species at the expense of others. We first tested whether hosts and parasites constrained each other's ability to expand or maintain their ranges. Second, we investigated whether range shifts represented an opportunity for new host‐parasite and parasite‐parasite interactions. We used multi‐species dynamic occupancy models with interactions, fitted to citizen‐science data, to estimate the contribution of interspecific interactions to range shifts and to quantify the change in species co‐occurrence probability over a 25‐year period. Parasites were able to track their hosts’ range shifts. We detected no deleterious effect of the parasites’ presence on either the local population viability of host species or the hosts’ ability to colonize newly suitable areas. In the recently diversified indigobird radiation (Vidua spp.), following bush encroachment, the new assemblages presented more potential opportunities for speciation via host switch, but also more potential for hybridization between extant lineages, also via host switch. Multi‐species dynamic occupancy models with interactions brought new insights into the feedbacks between range shifts, biotic interactions, and local demography: brood parasitism had little detected impact on extinction or colonization processes, but inversely the latter processes affected biotic interactions via the modification of co‐occurrence patterns. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-09T06:57:38.069097-05:
      DOI: 10.1111/1365-2656.12546
  • Trade‐offs and mixed infections in an obligate‐killing insect
    • Authors: Elizabeth M. Redman; Kenneth Wilson, Jenny S. Cory
      First page: 1200
      Abstract: Natural populations of pathogens are frequently composed of numerous interacting strains. Understanding what maintains this diversity remains a key focus of research in disease ecology. In addition, within‐host pathogen dynamics can have a strong impact on both infection outcome and the evolution of pathogen virulence and thus understanding the impact of pathogen diversity is important for disease management. We compared eight genetically distinguishable variants from Spodoptera exempta nucleopolyhedrovirus (SpexNPV) isolated from the African armyworm, Spodoptera exempta. NPVs are obligate killers and the vast majority of transmission‐stages are not released until after the host has died. The NPV variants differed significantly in their virulence and could be clustered into two groups based on their dose‐response curves. They also differed in their speed of kill and productivity (transmission potential) for S. exempta. The mixed‐genotype wild‐type SpexNPV, from which each variant was isolated, was significantly more virulent than any individual variant and its mean mortality rate was within the fastest group of individual variants. However, the wild‐type virus produced fewer new infectious stages than any single variant, which might reflect competition among the variants. A survival analysis, combining the mortality and speed of kill data, confirmed the superiority of the genetically‐mixed wild‐type virus over any single variant. S. exempta larvae infected with wild‐type SpexNPV were predicted to die 2.7 and 1.9 times faster than insects infected with isolates from either of the two clusters of genotypes. Theory suggests that there are likely to be trade‐offs between pathogen fitness traits. Across all larvae, there was a negative linear relationship between virus yield and speed of kill, such that more rapid host death carried the cost of producing fewer transmission stages. We also found a near‐significant relationship for the same trend at the inter‐variant level. However, there was no evidence for a significant relationship between the induced level of mortality and transmission potential (virus yield) or speed of kill. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-13T07:25:31.175242-05:
      DOI: 10.1111/1365-2656.12547
  • Slowing them down will make them lose: A role for attine ant crop fungus
           in defending pupae against infections'
    • First page: 1210
      Abstract: Fungus‐growing ants (Attini) have evolved an obligate dependency upon a basidiomycete fungus that they cultivate as their food. Less well known is that the crop fungus is also used by many attine species to cover their eggs, larvae and pupae. The adaptive functional significance of this brood covering is poorly understood. One hypothesis to account for this behaviour is that it is part of the pathogen protection portfolio when many thousands of sister workers live in close proximity and larvae and pupae are not protected by cells, as in bees and wasps, and are immobile. We performed behavioural observations on brood covering in the leaf‐cutting ant Acromyrmex echinatior and we experimentally manipulated mycelial cover on pupae and exposed them to the entomopathogenic fungus Metarhizium brunneum to test for a role in pathogen resistance. Our results show that active mycelial brood covering by workers is a behaviourally plastic trait that varies temporally, and across life stages and castes. The presence of a fungal cover on the pupae reduced the rate at which conidia appeared and the percentage of pupal surface that produced pathogen spores, compared to pupae that had fungal cover experimentally removed or naturally had no mycelial cover. Infected pupae with mycelium had higher survival rates than infected pupae without the cover, although this depended upon the time at which adult sister workers were allowed to interact with pupae. Finally, workers employed higher rates of metapleural gland grooming to infected pupae without mycelium than to infected pupae with mycelium. Our results imply that mycelial brood covering may play a significant role in suppressing the growth and subsequent spread of disease, thus adding a novel layer of protection to their defence portfolio. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-08T04:05:30.479329-05:
      DOI: 10.1111/1365-2656.12543
  • Experimental Insight into the Process of Parasite Community Assembly
    • Authors: S.A. Budischak; Eric P. Hoberg, Art Abrams, A.E. Jolles, V.O. Ezenwa
      First page: 1222
      Abstract: 1.Community assembly is a fundamental process that has long been a central focus in ecology. Extending community assembly theory to communities of co‐infecting parasites, we used a gastrointestinal nematode removal experiment in free‐ranging African buffalo to examine community assembly patterns and processes. 2.We first asked whether reassembled communities differ from undisturbed communities by comparing anthelmintic‐treated and control hosts. Next, we examined the temporal dynamics of assembly using a cross‐section of communities that reassembled for different periods of time since last experimental removal. Next, we tested for evidence of assembly processes that might drive such reassembly patterns: environmental filtering based on host traits (i.e. habitat patches), interspecific interactions, priority effects, and chance dispersal from the environmental pool of infective stages (i.e. the regional species pool). 3.On average, reassembled parasite communities had lower abundances, but were more diverse and even, and these patterns varied tightly with reassembly time. Over time, the communities within treated hosts progressively resembled controls as diversity and evenness decreased while total abundance increased. Notably, experimental removal allowed us to attribute observed differences in abundance, diversity, and evenness to the process of community assembly. 4.During early reassembly, parasite accumulation was biased towards a subordinate species and, by excluding stochastic assembly processes (i.e. chance dispersal and priority effects), we were able determine that early assembly is deterministic. Later in the reassembly process, we established that host traits, as well as stochastic dispersal from the environmental pool infective stages, can affect community composition. 5.Overall, our results suggest there is a high degree of resiliency and environmental dependence to the worm communities of buffalo. More generally, our data show that both deterministic and stochastic processes may play a role in the assembly of parasite communities of wild hosts, but their relative importance may vary temporally. Consequently, the best strategy for managing reassembling parasite communities may also need to shift over time. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-13T02:10:23.880302-05:
      DOI: 10.1111/1365-2656.12548
  • Parasite specialization in a unique habitat: hummingbirds as reservoirs of
           generalist blood parasites of Andean birds
    • First page: 1234
      Abstract: 1.Understanding how parasites fill their ecological niches requires information on the processes involved in the colonization and exploitation of unique host species. Switching to hosts with atypical attributes may favour generalists broadening their niches, or may promote specialization and parasite diversification as the consequence. 2.We analysed which blood parasites have successfully colonized hummingbirds, and how they have evolved to exploit such a unique habitat. We specifically asked (i) if the assemblage of Haemoproteus parasites of hummingbirds is the result of single or multiple colonization events, (ii) to what extent these parasites are specialized in hummingbirds or shared with other birds, and (iii) how hummingbirds contribute to sustain the populations of these parasites, in terms of both prevalence and infection intensity. 3.We sampled 169 hummingbirds of 19 species along an elevation gradient in Southern Ecuador to analyse the host specificity, diversity and infection intensity of Haemoproteus by molecular and microscopy techniques. In addition 736 birds of 112 species were analysed to explore if hummingbird parasites are shared with other birds. 4.Hummingbirds hosted a phylogenetically diverse assemblage of generalist Haemoproteus lineages shared with other host orders, indicating multiple colonization events. Among these parasites, Haemoproteus witti stood out as the most generalized. Interestingly, we found that infection intensities of this parasite were extremely low in passerines (with no detectable gametocytes) but very high in hummingbirds, with many gametocytes seen. Moreover, infection intensities of H. witti were positively correlated with prevalence across host species. 5.Our results show that hummingbirds have been colonised by generalist Haemoproteus lineages in multiple occasions. However, one of these generalist parasites (H. witti) seems to be highly dependent on hummingbirds, which arise as the most relevant reservoirs in terms of both prevalence and gametocytaemia. From this perspective, this generalist parasite may be viewed as a hummingbird specialist. This challenges the current paradigm of how to measure host specialization in these parasites, which has important implications to understand disease ecology. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-09T06:57:27.910713-05:
      DOI: 10.1111/1365-2656.12550
  • Fitness costs of animal medication: anti‐parasitic plant chemicals
           reduce fitness of monarch butterfly hosts
    • Authors: Leiling Tao; Kevin M. Hoang, Mark D. Hunter, Jacobus C. de Roode
      First page: 1246
      Abstract: 1.The emerging field of ecological immunology demonstrates that allocation by hosts to immune defense against parasites is constrained by the costs of those defenses. However, the costs of non‐immunological defenses, which are important alternatives to canonical immune systems, are less well characterized. Estimating such costs is essential for our understanding of the ecology and evolution of alternative host defense strategies. 2.Many animals have evolved medication behaviors, whereby they use anti‐parasitic compounds from their environment to protect themselves or their kin from parasitism. Documenting the costs of medication behaviors is complicated by natural variation in the medicinal components of diets and their covariance with other dietary components, such as macronutrients. 3.In the current study, we explore costs of the usage of anti‐parasitic compounds in monarch butterflies (Danaus plexippus), using natural variation in concentrations of anti‐parasitic compounds among plants. Upon infection by their specialist protozoan parasite Ophryocystis elektroscirrha, monarch butterflies can selectively oviposit on milkweed with high foliar concentrations of cardenolides, secondary chemicals that reduce parasite growth. Here, we show that these anti‐parasitic cardenolides can also impose significant costs on both uninfected and infected butterflies. 4.Among eight milkweed species that vary substantially in their foliar cardenolide concentration and composition, we observed opposing effects of cardenolides on monarch fitness traits. While high foliar cardenolide concentrations increased the tolerance of monarch butterflies to infection, they reduced the survival rate of caterpillars to adulthood. Additionally, although nonpolar cardenolide compounds decreased the spore load of infected butterflies, they also reduced the life span of uninfected butterflies, resulting in a hump‐shaped curve between cardenolide non‐polarity and the life span of infected butterflies. 5.Overall, our results suggest that the use of anti‐parasitic compounds carries substantial costs, which could constrain host investment in medication behaviors. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-10T10:01:43.673494-05:
      DOI: 10.1111/1365-2656.12558
  • Phenological mismatch and ontogenetic diet shifts interactively affect
           offspring condition in a passerine
    • Authors: Jelmer M. Samplonius; Elena F. Kappers, Stef Brands, Christiaan Both
      First page: 1255
      Abstract: 1.Climate change may cause phenological asynchrony between trophic levels, which can lead to mismatched reproduction in animals. Although indirect effects of mismatch on fitness are well described, direct effects on parental prey choice are not. Moreover, direct effects of prey variation on offspring condition throughout their early development are understudied. 2.Here we used camera trap data collected over two years to study the effects of trophic mismatch and nestling age on prey choice in pied flycatchers (Ficedula hypoleuca). Furthermore, we studied the effect of mismatch and variation in nestling diet on offspring condition. 3.Both experimentally induced and natural mismatch with the caterpillar peak negatively affected absolute and relative numbers of caterpillars and offspring condition (mass, tarsus and wing length), and positively affected absolute and relative numbers of flying insects in the nestling diet. Feeding more flying insects was negatively correlated with nestling day 12 mass. 4.Both descriptive and experimental data showed preferential feeding of spiders when nestlings were
      PubDate: 2016-06-06T07:25:40.978701-05:
      DOI: 10.1111/1365-2656.12554
  • Alternative prey use affects helminth parasite infections in gray wolves
    • Authors: Olwyn C. Friesen; James D. Roth
      First page: 1265
      Abstract: Predators affect prey populations not only through direct predation, but also by acting as definitive hosts for their parasites and completing parasite life cycles. Understanding the affects of parasitism on prey population dynamics requires knowing how their predators’ parasite community is affected by diet and prey availability. Ungulates, such as moose (Alces americanus) and white tailed deer (Odocoileus virginianus), are often important prey for wolves (Canis lupus), but wolves also consume a variety of alternative prey, including beaver (Castor canadensis) and snowshoe hare (Lepus americanus). The use of alternative prey, which may host different or fewer parasites than ungulates, could potentially reduce overall abundance of ungulate parasites within the ecosystem, benefiting both wolves and ungulate hosts. We examined parasites in wolf carcasses from eastern Manitoba and estimated wolf diet using stable isotope analysis. Taeniidae cestodes were present in most wolves (75%), reflecting a diet primarily comprised of ungulates, but nematodes were unexpectedly rare. Cestode abundance was negatively related to the wolf's δ13C value, indicating diet affects parasite abundance. Wolves that consumed a higher proportion of beaver and caribou (Rangifer tarandus), estimated using Bayesian mixing models, had lower cestode abundance, suggesting the use of these alternative prey can reduce parasite loads. Long‐term, the consumption of beavers may lower the abundance of adult parasites in wolves, eventually lowering parasite density in the region and ultimately benefiting ungulates that serve as intermediate hosts. Thus, alternative prey can affect both predator‐prey and host‐parasite interactions, and potentially affect food web dynamics. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-08T04:05:33.485771-05:
      DOI: 10.1111/1365-2656.12544
  • Causes and consequences of spatial variation in sex ratios in a declining
           bird species
    • Authors: Catriona A. Morrison; Robert A. Robinson, Jacquie A. Clark, Jennifer A. Gill
      First page: 1298
      Abstract: Male‐biased sex ratios occur in many bird species, particularly in those with small or declining populations, but the causes of these skews and their consequences for local population demography are rarely known. Within‐species variation in sex ratios can help to identify the demographic and behavioural processes associated with such biases. Small populations may be more likely to have skewed sex ratios if sex differences in survival, recruitment or dispersal vary with local abundance. Analyses of species with highly variable local abundances can help to identify these mechanisms and the implications for spatial variation in demography. Many migratory bird species are currently undergoing rapid and severe declines in abundance in parts of their breeding ranges and thus have sufficient spatial variation in abundance to explore the extent of sex ratio biases, their causes and implications. Using national‐scale bird ringing data for one such species (willow warbler, Phylloscopus trochilus), we show that sex ratios vary greatly across Britain and that male‐biased sites are more frequent in areas of low abundance, which are now widespread across much of south and east England. These sex ratio biases are sufficient to impact local productivity, as the relative number of juveniles caught at survey sites declines significantly with increasing sex ratio skew. Sex differences in survival could influence this sex ratio variation, but we find little evidence for sex differences in survival increasing with sex ratio skew. In addition, sex ratios have become male‐biased over the last two decades, but there are no such trends in adult survival rates for males or females. This suggests that lower female recruitment into low abundance sites is contributing to these skews. These findings suggest that male‐biased sex ratios in small and declining populations can arise through local‐scale sex differences in survival and dispersal, with females recruiting disproportionately into larger populations. Given the high level of spatial variation in population declines and abundance of many migratory bird species across Europe at present, male‐biased small populations may be increasingly common. As singing males are the primary records used in surveys of these species, and as unpaired males often sing throughout the breeding season, local sex ratio biases could also be masking the true extent of these population declines. Small populations of migratory warblers are more likely to be male‐biased and these small biased populations are increasingly widespread throughout Britain.
      PubDate: 2016-07-08T00:00:03.567125-05:
      DOI: 10.1111/1365-2656.12556
  • Piscivorous fish exhibit temperature‐influenced binge feeding during
           an annual prey pulse
    • Authors: Nathan B. Furey; Scott G. Hinch, Matthew G. Mesa, David A. Beauchamp
      First page: 1307
      Abstract: Understanding the limits of consumption is important for determining trophic influences on ecosystems and predator adaptations to inconsistent prey availability. Fishes have been observed to consume beyond what is sustainable (i.e. digested on a daily basis), but this phenomenon of hyperphagia (or binge‐feeding) is largely overlooked. We expect hyperphagia to be a short‐term (1‐day) event that is facilitated by gut volume providing capacity to store consumed food during periods of high prey availability to be later digested. We define how temperature, body size and food availability influence the degree of binge‐feeding by comparing field observations with laboratory experiments of bull trout (Salvelinus confluentus), a large freshwater piscivore that experiences highly variable prey pulses. We also simulated bull trout consumption and growth during salmon smolt outmigrations under two scenarios: 1) daily consumption being dependent upon bioenergetically sustainable rates and 2) daily consumption being dependent upon available gut volume (i.e. consumption is equal to gut volume when empty and otherwise ‘topping off’ based on sustainable digestion rates). One‐day consumption by laboratory‐held bull trout during the first day of feeding experiments after fasting exceeded bioenergetically sustainable rates by 12‐ to 87‐fold at low temperatures (3 °C) and by  ˜1·3‐fold at 20 °C. The degree of binge‐feeding by bull trout in the field was slightly reduced but largely in agreement with laboratory estimates, especially when prey availability was extremely high [during a sockeye salmon (Oncorhynchus nerka) smolt outmigration and at a counting fence where smolts are funnelled into high densities]. Consumption by bull trout at other settings were lower and more variable, but still regularly hyperphagic. Simulations demonstrated the ability to binge‐feed increased cumulative consumption (16–32%) and cumulative growth (19–110%) relative to only feeding at bioenergetically sustainable rates during the  ˜1‐month smolt outmigration period. Our results indicate the ability for predators to maximize short‐term consumption when prey are available can be extreme and is limited primarily by gut volume, then mediated by temperature; thus, predator–prey relationships may be more dependent upon prey availability than traditional bioenergetic models suggest. Binge‐feeding has important implications for energy budgets of consumers as well as acute predation impacts on prey. Short‐term binge‐feeding by bull trout in the laboratory and in the field (during a prey pulse) were quantified and found to be extreme and largely not limited by low temperatures. Thus, the ability for predators to maximize short‐term consumption when prey are available is greater than traditional bioenergetics models suggest.
      PubDate: 2016-07-26T01:00:32.135822-05:
      DOI: 10.1111/1365-2656.12565
  • Impact of changing wind conditions on foraging and incubation success in
           male and female wandering albatrosses
    • First page: 1318
      Abstract: 1.Wind is an important climatic factor for flying animals as by affecting their locomotion, it can deeply impact their life‐history characteristics. 2.In the context of globally changing wind patterns, we investigated the mechanisms underlying recently reported increase in body mass of a population of wandering albatrosses (Diomedea exulans) with increasing wind speed over time. 3.We built a foraging model detailing the effects of wind on movement statistics and ultimately on mass gained by the forager and mass lost by the incubating partner.We then simulated the body mass of incubating pairs under varying wind scenarios.We tracked the frequency at which critical mass leading to nest abandonment was reached to assess incubation success. 4.We found that wandering albatrosses behave as time‐minimizers during incubation as mass gain was independent of any movement statistics but decreased with increasing mass at departure.Individuals forage until their energy requirements, which are determined by their body conditions, are fulfilled.This can come at the cost of their partner's condition as mass loss of the incubating partner depended on trip duration.This behaviour is consistent with strategies of long‐lived species which favoured their own survival over their current reproductive attempt.In addition, wind speed increased ground speed which in turn reduced trip duration and males foraged further away than females at high ground speed. 5.Contrasted against an independent dataset, the simulation performed sat‐isfactorily for males but less so for females under current wind conditions.The simulation predicted an increase in male body mass growth rate with increasing wind speed whereas females’ rate decreased. This trend may provide an explanation for the observed increase in mass of males but not of females.Conversely, the simulation predicted very few nest abandonments,which is in line with the high breeding success of this species and is contrary to the hypothesis that wind patterns impact incubation success by altering foraging movement. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-17T08:45:49.374935-05:
      DOI: 10.1111/1365-2656.12552
  • Field‐based experimental acidification alters fouling community
           structure and reduces diversity
    • Authors: Norah E. M. Brown; Thomas W. Therriault, Christopher D. G. Harley
      First page: 1328
      Abstract: 1.Increasing levels of CO2 in the atmosphere are affecting ocean chemistry, leading to increased acidification (i.e., decreased pH) and reductions in calcium carbonate saturation state. 2.Many species are likely to respond to acidification, but the direction and magnitude of these responses will be based on interspecific and ontogenetic variation in physiology and the relative importance of calcification. Differential responses to ocean acidification among species will likely result in important changes in community structure and diversity. 3.To characterize potential impacts of ocean acidification on community composition and structure, we examined the response of a marine fouling community to experimental CO2 enrichment in field‐deployed flow‐through mesocosm systems. 4.Acidification significantly altered community structure by altering the relative abundances of species and reduced community variability, resulting in more homogenous biofouling communities from one experimental tile to the next both among and within the acidified mesocosms. Mussel (Mytilus trossulus) recruitment was reduced by over 30% in the elevated CO2 treatment compared to the ambient treatment by the end of the experiment. Strong differences in mussel cover (up to 40% lower in acidified conditions) developed over the second half of the 10‐week experiment. Acidification did not appear to affect mussel growth, as average mussel sizes were similar between treatments at the end of the experiment. Hydroid (Obelia dichotoma) cover was significantly reduced in the elevated CO2 treatment after eight weeks. Conversely, the percent cover of bryozoan colonies (Mebranipora membranacea) was higher under acidified conditions with differences becoming apparent after six weeks. Neither recruitment nor final size of barnacles (Balanus crenatus) was affected by acidification. By the end of the experiment, diversity was 41% lower in the acidified treatment relative to ambient conditions. 5.Overall, our findings support the general expectation that OA will simplify marine communities by acting on important ecological processes that ultimately determine community structure and diversity. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-10T10:45:27.185783-05:
      DOI: 10.1111/1365-2656.12557
  • The price of associating with breeders in the cooperatively breeding
           chestnut‐crowned babbler: foraging constraints, survival and sociality
    • Authors: E Sorato; S C Griffith, AF Russell
      First page: 1340
      Abstract: Understanding the costs of living with breeders might offer new insights into the factors that counter evolutionary transitions from selfish individuals to cooperative societies. While selection on early dispersal is well‐understood, it is less clear whether costs are also associated with remaining with family members during subsequent breeding; a pre‐requisite to the evolution of kin‐based cooperation. We propose and test the hypothesis that living in groups containing breeders is costly and that such costs are exacerbated by increasing group size. For example, in group‐living central‐place foragers, group members might suffer from resource depletion when foraging in a restricted area during breeding and significant costs of repeatedly travelling between foraging patches and the site of offspring. Using the cooperatively breeding chestnut‐crowned babbler (Pomatostomus ruficeps), for which grouping during breeding is obligatory, we show that reproduction is associated with substantially reduced foraging areas and evidence of resource depletion, particularly in larger groups. Such effects largely persisted from the onset of incubation through to offspring independence 4‐5 months later. All group members, irrespective of their breeder or helper status, lost significant body mass over this period, and, in males, mass loss was associated with reduced inter‐annual survival. Although babblers are constrained from living outside of breeding groups due to high risks of predation and the poor success of breeding without helpers, we suggest that the effects we describe may generally select against group‐living during breeding attempts in species where constraints to independent breeding and costs of dispersal are less acute. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-02T07:46:22.229218-05:
      DOI: 10.1111/1365-2656.12539
  • Street lighting: sex‐independent impacts on moth movement
    • First page: 1352
      Abstract: 1.Artificial lights have become an integral and welcome part of our urban and peri‐urban environments. However, recent research has highlighted the potentially negative ecological consequences of ubiquitous artificial light. In particular, insects, especially moths, are expected to be negatively impacted by the presence of artificial lights. Previous research with light traps has shown a male‐biased attraction to light in moths. 2.In this study, we sought to determine if street lights could limit moth dispersal and if there was any sex bias in attraction to light. More specifically, we aimed to determine sex specific attraction radii for moths to street lights. 3.We tested these hypotheses by collecting moths for two years at an experimental setup. To estimate the attraction radii we developed a Markov model and related it to the acquired data. 4.Utilizing multinomial statistics, we found that attraction rates to lights in the middle of the matrix were substantially lower than predicted by the null hypothesis of equal attraction level (0.44 times). With the Markov model, we estimated that a corner‐light was 2.77 times more attractive than a wing‐light with an equivalent attraction radius of c. 23m around each light. We found neither sexual differences in the attraction rate nor in the attraction radius of males and females. Since we captured three times more males than females, we conclude that sex ratios are representative of operational sex ratios or of different flight activities. 5.These results provide evidence for street lights to limit moth dispersal, and that they seem to act equally on male and female moths. Consequently, public lighting might divide a suitable landscape into many small habitats. Therefore, it is reasonable to assume i) that public lighting near hedges and bushes or field margins reduces the quality of these important habitat structures, and ii) that public lighting near important habitat structures but not interfering with local movement may affect moth movement between patches. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-13T07:30:26.84133-05:0
      DOI: 10.1111/1365-2656.12540
  • Kin effects on energy allocation in group‐living ground squirrels
    • Authors: Vincent A. Viblanc; Claire Saraux, Jan O. Murie, F. Stephen Dobson
      First page: 1361
      Abstract: The social environment has potent effects on individual phenotype and fitness in group‐living species. We asked whether the presence of kin might act on energy allocation, a central aspect of life‐history variation. Using a 22‐year data set on reproductive and somatic allocations in Columbian ground squirrels (Urocitellus columbianus), we tested the effects of co‐breeding and non‐breeding kin on the fitness and energy allocation balance between reproduction and personal body condition of individual females. Greater numbers of co‐breeding kin had a positive effect on the number of offspring weaned, through the mechanism of altering energy allocation patterns. On average, females with higher numbers of co‐breeding kin did not increase energy income but biased energy allocation towards reproduction. Co‐breeding female kin ground squirrels maintain close nest burrows, likely providing a social buffer against territorial invasions from non‐kin ground squirrels. Lower aggressiveness, lower risks of infanticide from female kin and greater protection of territorial boundaries may allow individual females to derive net fitness benefits via their energy allocation strategies. We demonstrated the importance of kin effects on a fundamental life‐history trade‐off. This study highlights the effects of the social environment (kin numbers) on a fundamental life history trade‐off: the allocation of energy to reproductive or somatic functions.
      PubDate: 2016-06-06T00:00:05.812116-05:
      DOI: 10.1111/1365-2656.12541
  • Contrasting patterns of short‐term indirect seed‐seed interactions
           mediated by scatter‐hoarding rodents
    • Authors: Zhishu Xiao; Zhibin Zhang
      First page: 1370
      Abstract: It is well known that direct effects of seed predators or dispersers can have strong effects on seedling establishment. However, we have limited knowledge about the indirect species interactions between seeds of different species that are mediated by shared seed predators and/or dispersers and their consequences for plant demography and diversity. Because scatter‐hoarding rodents as seed dispersers may leave some hoarded seeds uneaten, scatter‐hoarding may serve to increase seed survival and dispersal. Consequently, the presence of heterospecific seeds could alter whether the indirect interactions mediated by scatter‐hoarding rodents have a net positive effect, creating apparent mutualism between seed species, or a net negative effect, creating apparent competition between seed species. We present a testable framework to measure short‐term indirect effects between co‐occurring plant species mediated by seed scatter‐hoarding rodents. We tested this framework in a subtropical forest in Southwest China using a replacement design and tracked the fate of individually‐tagged seeds in experimental patches. We manipulated the benefits to rodents by using low‐tannin dormant chestnuts as palatable food and high‐tannin non‐dormant acorns as unpalatable food. We found that seed palatability changed the amount of scatter‐hoarding that occurred when seeds co‐occurred either among or within patches. Consistent with our predictions, scatter‐hoarding rodents created apparent mutualism through increasing seed removal and seed‐caching, and enhancing survival, of both plant species in mixed patches compared with monospecific patches. However, if we ignore scatter hoarding and treat all seed harvest as seed predation (and not dispersal), then apparent competition between palatable chestnuts and unpalatable acorns was also observed. This study is the first to demonstrate that foraging decisions by scatter‐hoarding animals to scatter hoard seeds for later consumption (or loss) or consume them can influence indirect effects among co‐occurring seeds, and rodent‐mediated indirect effects vary depending on whether the harvested seeds are hoarded or eaten. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-31T04:10:28.326152-05:
      DOI: 10.1111/1365-2656.12542
  • Thermal preference predicts animal personality in Nile tilapia Oreochromis
    • Authors: M. Cerqueira; S. Rey, T. Silva, Zoe Featherstone, Margaret Crumlish, S. MacKenzie
      First page: 1389
      Abstract: 1.Environmental temperature gradients provide habitat structure in which fish orientate and individual thermal choice may reflect an essential integrated response to the environment. The use of subtle thermal gradients likely impacts upon specific physiological and behavioural processes reflected as a suite of traits described by animal personality. In this study we examine the relationship between thermal choice, animal personality and the impact of infection upon this interaction. 2.We predicted that thermal choice in Nile tilapia Oreochromis niloticus reflects distinct personality traits and that under a challenge individuals exhibit differential thermal distribution. 3.Nile Tilapia were screened following two different protocols: 1) a suite of individual behavioural tests to screen for personality and 2) thermal choice in a custom‐built tank with a thermal gradient (TCH tank) ranging from 21 to 33 °C. A first set of fish were screened for behaviour and then thermal preference and a second set were tested in the opposite fashion; thermal then behaviour. The final thermal distribution of the fish after 48 h was assessed reflecting final thermal preferendum. Additionally, fish were then challenged using a bacterial Streptococcus iniae model infection to assess the behavioural fever response of proactive and reactive fish. 4.Results showed that individuals with preference for higher temperatures were also classified as proactive with behavioural tests and reactive contemporaries chose significantly lower water temperatures. All groups exhibited behavioural fever recovering personality‐specific thermal preferences after 5 days. 5.Our results show that thermal preference can be used as a proxy to assess personality traits in Nile tilapia and it is a central factor to understand the adaptive meaning of animal personality within a population. Importantly, response to infection by expressing behavioural fever overrides personality related thermal choice. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-24T02:31:33.630447-05:
      DOI: 10.1111/1365-2656.12555
  • Evaluating random search strategies in three mammals from distinct feeding
    • First page: 1411
      Abstract: 1.Searching allows animals to find food, mates, shelter, and other resources essential for survival and reproduction, and is thus among the most important activities performed by animals. Theory predicts that animals will use random search strategies in highly variable and unpredictable environments. Two prominent models have been suggested for animals searching in sparse and heterogeneous environments: (i) the Levy walk and (ii) the composite correlated random walk (CCRW) and its associated area‐restricted search behaviour. Until recently, it was difficult to differentiate between the movement patterns of these two strategies. 2.Using a new method that assesses whether movement patterns are consistent with these two strategies and two other common random search strategies, we investigated the movement behaviour of three species inhabiting sparse northern environments: woodland caribou (Rangifer tarandus caribou), barren ground grizzly bear (Ursus arctos), and polar bear (U. maritimus). These three species vary widely in their diets, and thus allow us to contrast the movement patterns of animals from different feeding guilds. 3.Our results showed that, although more traditional methods would have found evidence for the Levy walk for some individuals, a comparison of the Levy walk to CCRWs showed stronger support for the latter. While a CCRW was the best model for most individuals, there was a range of support for its absolute fit. A CCRW was sufficient to explain the movement of nearly half of herbivorous caribou and a quarter of omnivorous grizzly bears, but was insufficient to explain the movement of all carnivorous polar bears. 4.Strong evidence for CCRW movement patterns suggests that many individuals may use a multiphasic movement strategy rather than one‐behaviour strategies such as the Levy walk. The fact that the best model was insufficient to describe the movement paths of many individuals suggests that some animals living in sparse environments may use strategies that are more complicated than those described by the standard random search models. Thus, our results indicate a need to develop movement models that incorporate factors such as the perceptual and cognitive capacities of animals. This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-21T06:12:01.378226-05:
      DOI: 10.1111/1365-2656.12562
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