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ZOOLOGY (118 journals)                  1 2     

Acta Herpetologica     Open Access   (4 followers)
Acta Theriologica     Full-text available via subscription   (6 followers)
Acta Zoologica     Hybrid Journal   (3 followers)
Acta zoológica mexicana     Open Access  
African Invertebrates     Open Access  
African Journal of Herpetology     Full-text available via subscription   (1 follower)
African Zoology     Open Access   (6 followers)
animal     Hybrid Journal   (3 followers)
Animal Behaviour     Hybrid Journal   (128 followers)
Animal Biology     Full-text available via subscription   (8 followers)
Animal Biology & Animal Husbandry     Open Access   (5 followers)
Animal Biotelemetry     Open Access   (2 followers)
Animal Genetics     Hybrid Journal   (6 followers)
Animal Migration     Open Access  
Animal Studies Journal     Open Access   (4 followers)
Annales UMCS, Zootechnica     Open Access   (1 follower)
Annales Zoologici     Full-text available via subscription  
Annales Zoologici Fennici     Open Access  
Annals of Animal Science     Open Access   (1 follower)
Annual Review of Animal Biosciences     Full-text available via subscription   (4 followers)
Anthropozoologica     Full-text available via subscription   (3 followers)
Anthrozoos : A Multidisciplinary Journal of The Interactions of People & Animals     Full-text available via subscription   (3 followers)
Applied Animal Behaviour Science     Hybrid Journal   (10 followers)
Applied Entomology and Zoology     Partially Free   (3 followers)
Aquatic Mammals     Full-text available via subscription   (3 followers)
Aquatic Sciences     Hybrid Journal   (10 followers)
Asian Journal of Animal and Veterinary Advances     Open Access   (5 followers)
Australian Journal of Zoology     Hybrid Journal   (1 follower)
Bioacoustics : The International Journal of Animal Sound and its Recording     Partially Free   (2 followers)
Bird Conservation International     Hybrid Journal   (12 followers)
Bird Study     Full-text available via subscription   (10 followers)
Brazilian Journal of Veterinary Research and Animal Science     Open Access   (5 followers)
British Birds     Full-text available via subscription   (6 followers)
Bulletin of the Museum of Comparative Zoology     Full-text available via subscription   (2 followers)
Canadian Journal of Animal Science     Full-text available via subscription   (4 followers)
Canadian Journal of Zoology     Full-text available via subscription   (11 followers)
Contributions to Zoology     Open Access   (3 followers)
Der Zoologische Garten     Full-text available via subscription   (2 followers)
Ecology of Freshwater Fish     Hybrid Journal   (14 followers)
Edentata     Open Access  
European Journal of Taxonomy     Open Access   (1 follower)
Euscorpius     Open Access  
EvoDevo     Open Access   (1 follower)
Fieldiana Zoology     Full-text available via subscription   (2 followers)
Fish and Fisheries     Hybrid Journal   (25 followers)
Frontiers in Zoology     Open Access   (6 followers)
Graellsia     Open Access  
Hystrix, the Italian Journal of Mammalogy     Open Access  
i-Perception     Open Access   (3 followers)
Iheringia. Série Zoologia     Open Access  
In Vitro Cellular & Developmental Biology - Animal     Hybrid Journal   (1 follower)
Integrative Zoology     Hybrid Journal  
International Journal of Odonatology     Hybrid Journal   (1 follower)
International Journal of Zoological Research     Open Access   (2 followers)
International Journal of Zoology     Open Access   (2 followers)
International Zoo Yearbook     Hybrid Journal  
Invertebrate Reproduction & Development     Hybrid Journal   (2 followers)
ISRN Zoology     Open Access   (3 followers)
Italian Journal of Animal Science     Open Access   (2 followers)
Italian Journal of Zoology     Hybrid Journal   (2 followers)
Journal of Agrobiology     Open Access   (2 followers)
Journal of Animal Ecology     Hybrid Journal   (24 followers)
Journal of Animal Physiology and Animal Nutrition     Hybrid Journal   (3 followers)
Journal of Apicultural Science     Open Access  
Journal of Basic & Applied Zoology : Physiology     Open Access  
Journal of Experimental Zoology Part A: Ecological Genetics and Physiology     Hybrid Journal   (2 followers)
Journal of Experimental Zoology Part B : Molecular and Developmental Evolution     Hybrid Journal  
Journal of Freshwater Ecology     Hybrid Journal   (9 followers)
Journal of Insects     Open Access  
Journal of Venomous Animals and Toxins     Open Access   (3 followers)
Journal of Venomous Animals and Toxins including Tropical Diseases     Open Access  
Journal of Wildlife Management     Hybrid Journal   (22 followers)
Journal of Zoo and Aquarium Research     Open Access  
Journal of Zoological Systematics and Evolutionary Research     Hybrid Journal   (4 followers)
Journal of Zoology     Hybrid Journal   (9 followers)
Laboratory Animals     Hybrid Journal   (8 followers)
Mammalia     Full-text available via subscription   (6 followers)
Marine Ecology Progress Series MEPS     Full-text available via subscription   (6 followers)
Mastozoología Neotropical     Open Access  
Memorias de la Conferencia Interna en Medicina y Aprovechamiento de Fauna Silvestre, Exótica y no Convencional     Open Access  
Neotropical Primates     Open Access  
New Zealand Journal of Zoology     Hybrid Journal  
Papéis Avulsos de Zoologia     Open Access   (1 follower)
Parasite     Open Access   (5 followers)
Physiological and Biochemical Zoology     Full-text available via subscription   (5 followers)
Polish Journal of Entomology     Open Access   (2 followers)
Protist Genomics     Open Access  
Research in Zoology     Open Access   (1 follower)
Revista Brasileira de Zoologia     Open Access  
Revista de Biología Marina y Oceanografía     Open Access   (1 follower)
Revista de Zoologia     Open Access   (1 follower)
Revista del Museo Argentino de Ciencias Naturales     Open Access  
Russian Journal of Herpetology     Full-text available via subscription   (1 follower)
Scientific Journal of Animal Science     Open Access   (2 followers)
Scientific Journal of Zoology     Open Access   (2 followers)
SHILAP Revista de Lepidopterologia     Open Access   (2 followers)
Skeletal Muscle     Open Access   (1 follower)
Sri Lanka Journal of Aquatic Sciences     Open Access  
Travaux du Muséum National d’Histoire Naturelle “Grigore Antipa”     Open Access  
Tropical Zoology     Partially Free   (1 follower)

        1 2     

Journal of Animal Ecology    [26 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  [1594 journals]   [SJR: 2.606]   [H-I: 94]
  • Body size, carry‐over effects and survival in a seasonal
           environment: consequences for population dynamics
    • Abstract: 1.In seasonal populations, vital rates are not only determined by the direct effects of density at the beginning of each season, but also by density at the beginning of past seasons. Such delayed density‐dependence can arise via non‐lethal effects on individuals that carry‐over to influence per capita rates. 2.In this study, we examine (a) whether parental breeding density influences offspring size, (b) how this could carry over to affect offspring survival during the subsequent non‐breeding period, and (c) the population consequences of this relationship. 3.Using Drosophila melanogaster, the common fruit fly, submitted to distinct breeding and non‐breeding seasons, we first used a controlled lab experiment to show that high parental breeding density leads to small offspring size, which then affects offspring survival during the non‐breeding period but only at high non‐breeding densities. 4.Similar to our experimental results, we then show that a model with the interaction between parental breeding density and offspring density at the beginning of the non‐breeding season best explained offspring survival over 36 replicated generations. 5.Finally, we developed a bi‐seasonal model to show that the positive relationship between parental density and offspring survival dampened fluctuations in population size between breeding and non‐breeding seasons. 6.These results highlight how variation in parental density can lead to differences in offspring quality which result in important non‐lethal effects that carry‐over to influence per capita rates the following season, and demonstrate how this phenomenon can have important implications for the long‐term dynamics of seasonal populations. This article is protected by copyright. All rights reserved.
  • Year‐round effects of climate on demographic parameters of an
           arctic–nesting goose species
    • Abstract: 1. Understanding how climate change will affect animal population dynamics remains a major challenge, especially in long‐distant migrants exposed to different climatic regimes throughout their annual cycle. 2. We evaluated the effect of temperature throughout the annual cycle on demographic parameters (age‐specific survival and recruitment, breeding propensity, and fecundity) of the greater snow goose (Chen caerulescens atlantica L.), an arctic‐nesting species. Since this is a hunted species, we used the theory of exploited populations to estimate hunting mortality separately from natural mortality in order to evaluate climatic effects only on the latter form of mortality. 3. Our analysis was based on a 22‐year marking study (n = 27,150 females) and included live recaptures at the breeding colony and dead recoveries from hunters. We tested the effect of climatic covariates by applying a procedure that accounts for unexplained environmental variation in the demographic parameter to a multistate Capture‐Mark‐Recapture recruitment model. 4. Breeding propensity, clutch size and hatching probability all increased with high temperatures on the breeding grounds. First‐year survival to natural causes of mortality increased when temperature was high at the end of the summer whereas adult survival was not affected by temperature. On the contrary, accession to reproduction decreased with warmer climatic conditions during the non‐breeding season. 5. Survival was strongly negatively related to hunting mortality in adults, as expected, but not in first‐year birds, which suggests the possibility of compensation between natural and hunting mortality in the latter group. 6. We show that events occurring both at and away from the breeding ground can affect the demography of migratory birds, either directly or through carry‐over effects, and sometimes in opposite ways. This highlights the need to account for the whole life cycle of an animal when attempting to project the response of populations to future climatic changes. This article is protected by copyright. All rights reserved.
  • Ant functional responses along environmental gradients
    • Abstract: Understanding species distributions and diversity gradients is a central challenge in ecology and requires prior knowledge of the functional traits mediating species’ survival under particular environmental conditions. While the functional ecology of plants has been reasonably well explored, much less is known about that of animals. Ants are among the most diverse, abundant, and ecologically significant organisms on earth, and they perform a great variety of ecological functions. In this study, we analyze how the functional species traits present in ant communities vary along broad gradients in climate, productivity, and vegetation type in the southwestern Mediterranean. To this end, we compiled one of the largest animal databases to date: it contains information on 211 local ant communities (including eight climate variables, productivity, and vegetation type) and 124 ant species, for which 10 functional traits are described. We used traits that characterize different dimensions of the ant functional niche with respect to morphology, life‐history and behavior at both individual‐ and colony‐level. We calculated two complementary functional trait community indices (‘trait average’ and ‘trait dissimilarity’) for each trait, and we analyzed how they varied along the three different gradients using generalized least squares (GLS) models that accounted for spatial autocorrelation. Our results show that productivity, vegetation type, and, to a lesser extent, each climate variable per se might play an important role in shaping the occurrence of functional species traits in ant communities. Among the climate variables, temperature and precipitation seasonality had a much higher influence on functional responses than their mean values, whose effects were almost lacking. Our results suggest that strong relationships might exist between the abiotic environment and the distribution of functional traits among southwestern Mediterranean ant communities. This finding indicates that functional traits may modulate the responses of ant species to the environment. Since these traits act as the link between species distributions and the environment, they could potentially be used to predict community changes under future global change scenarios. This article is protected by copyright. All rights reserved.
  • Revisiting food‐based models of territoriality in solitary predators
    • Abstract: 1. Food availability is considered a major factor determining spacing behaviour in territorial species, especially for females. Theoretically, spatial overlap (considered the opposite of territoriality) and food availability are related in a non‐linear manner (hypothesized inverted‐U function), with high overlap levels at the extremes of a food availability gradient and low overlap at intermediate levels of this gradient. Similar patterns are expected for encounter frequencies owing to its expected correlation with spatial overlap. However, these predictions have rarely been tested in highly structured social systems on a broad gradient of food availability, which implicitly requires experimental manipulation. 2. We test these predictions in a solitary, territorial and trophic specialist, the Iberian lynx Lynx pardinus, taking advantage of a three‐decade dataset of spatial behaviour in different scenarios of food availability (i.e. rabbit density). 3. In contrast with expectations, home range overlap among resident females was low (median overlap index = 0.08, range 0‐0.57) and core area overlap was nearly nil (median overlap index = 0, range 0‐0.22) throughout the entire gradient of prey availability. Furthermore, spatial associations between pairs of females were negligible regardless marked variation in prey availability. Therefore, we did not find support for a model of flexible lynx territoriality driven by food availability. 4. Our results suggest that the exclusive use of space in the Iberian lynx was not related to food. Lack of influence of prey availability on lynx territoriality may be adaptive to cope with the consequences of frequent drought‐induced periods of prey scarcity or other disturbance typically affecting wild rabbit populations in Mediterranean environments. Thus, lynx would adopt an obstinate strategy of territoriality that consists in defending exclusive areas across a broad range of resource availability ensuring an exclusive access to the minimum amount of prey necessary for survival and eventually reproduction even during periods of prey scarcity. However, we found signs that territoriality was influenced by lynx density in a non‐linear fashion. Our results suggest the occurrence of population regulation through territoriality in this species. This article is protected by copyright. All rights reserved.
  • Experimentally decoupling reproductive investment from energy storage to
           test the functional basis of a life‐history tradeoff
    • Abstract: The ubiquitous life‐history tradeoff between reproduction and survival has long been hypothesized to reflect underlying energy‐allocation tradeoffs between reproductive investment and processes related to self‐maintenance. Although recent work has questioned whether energy‐allocation models provide sufficient explanations for the survival cost of reproduction, direct tests of this hypothesis are rare, especially in wild populations. This hypothesis was tested in a wild population of brown anole lizards (Anolis sagrei) using a two‐step experiment. First, stepwise variation in reproductive investment was created using unilateral and bilateral ovariectomy (OVX) along with intact (SHAM) control. Next, this manipulation was decoupled from its downstream effects on energy storage by surgically ablating the abdominal fat stores from half of the females in each reproductive treatment. As predicted, unilateral OVX (intermediate reproductive investment) induced levels of growth, body condition, fat storage, and breeding‐season survival that were intermediate between the high levels of bilateral OVX (no reproductive investment) and the low levels of SHAM (full reproductive investment). Ablation of abdominal fat bodies had a strong and persistent effect on energy stores, but it did not influence post‐breeding survival in any of the three reproductive treatments. This suggests that the energetic savings of reduced reproductive investment does not directly enhance post‐breeding survival, with the caveat that only one aspect of energy storage was manipulated and OVX itself had no overall effect on post‐breeding survival. This study supports the emerging view that simple energy‐allocation models may often be insufficient as explanations for the life‐history tradeoff between reproduction and survival. This article is protected by copyright. All rights reserved.
  • Cheetahs and wild dogs show contrasting patterns of suppression by lions
    • Abstract: Top predators can dramatically suppress populations of smaller predators, with cascading effects throughout communities, and this pressure is often unquestioningy accepted as a constraint on mesopredator populations. In this study, we reassess whether African lions suppress populations of cheetahs and African wild dogs, and examine possible mechanisms for coexistence between these species. Using long‐term records from Serengeti National Park, we tested 30 years of population data for evidence of mesopredator suppression and we examined six years of concurrent radio‐telemetry data for evidence of large‐scale spatial displacement. The Serengeti lion population nearly tripled between 1966 and 1998; during this time, wild dogs declined but cheetah numbers remained largely unchanged. Prior to their local extinction, wild dogs primarily occupied low‐lion density areas, and apparently abandoned the long‐term study area as the lion population “saturated” the region. In contrast, cheetahs mostly utilized areas of high lion density, and the stability of the cheetah population indicates that neither high levels of lion‐inflicted mortality nor behavioral avoidance inflict sufficient demographic consequences to translate into population‐level effects. Population data from fenced reserves in southern Africa revealed a similar contrast between wild dogs and cheetahs in their ability to coexist with lions. These findings demonstrate differential responses of subordinate species within the same guild and challenge a widespread perception that lions undermine cheetah conservation efforts. Paired with several recent studies that document fine‐scale lion‐avoidance by cheetahs, this study further highlights fine‐scale spatial avoidance as a possible mechanism for mitigating mesopredator suppression. This article is protected by copyright. All rights reserved.
  • Disentangling the effects of exposure and susceptibility on transmission
           of the zoonotic parasite Schistosoma mansoni
    • Abstract: For all parasites, transmission is composed of two processes: host contact with parasites (“exposure”) and risk of infection given such contact (“susceptibility”). Classic models, such as mass action (density‐dependent) transmission, lump these processes together. However, separating these processes could enhance predictions for disease dynamics, especially for free‐living parasites. Here we outline three transmission models that partition exposure and susceptibility. Using data from a study of Schistosoma mansoni (trematode) infections in Biomphalaria glabrata snails, we competed these three models against four alternative models, including the mass action model (which lumps exposure and susceptibility). The models that separately accounted for exposure and susceptibility best predicted prevalence across the density gradients of hosts and parasites, outperforming all other models based on Akaike Information Criterion. When embedded into a dynamic epidemiological model, the exposure‐explicit models all predicted lower equilibrium densities of infected snails and human‐infectious cercariae. Thus, population‐level epidemiological models that utilize the classic mass action transmission model might overestimate human risk of schistosomiasis. More generally, the presented approach for disentangling exposure and susceptibility can distinguish between behavioral and immunological resistance, identify mechanisms of “disease dilution”, and provide a more complete dissection of drivers of parasite transmission. This article is protected by copyright. All rights reserved.
  • The effect of fire on habitat selection of mammalian herbivores: the role
           of body size and vegetation characteristics
    • Abstract: 1. Given the role of fire in shaping ecosystems, especially grasslands and savannahs, it is important to understand its broader impact on these systems. Post‐fire stimulation of plant nutrients is thought to benefit grazing mammals and explain their preference for burned areas. However, fire also reduces vegetation height and increases visibility, thereby potentially reducing predation risk. Consequently, fire may be more beneficial to smaller herbivores, with higher nutritional needs and greater risks of predation. 2. We tested the impacts of burning on different sized herbivores’ habitat preference in Serengeti National Park, as mediated by burning's effects on vegetation height, live to dead biomass ratio, and leaf nutrients. 3. Burning caused a less than four month increase in leaf nitrogen (N), and leaf non‐N nutrients (copper (Cu), potassium (K), and magnesium (Mg)), and a decrease in vegetation height and live:dead biomass. During this period, total herbivore counts were higher on burned areas. Generally, smaller herbivores preferred burned areas, more strongly than larger herbivores. 4. Unfortunately, it was not possible to determine the vegetation characteristics that explained burned area preference for each of the herbivore species observed. However, total herbivore abundance and impala (Aepyceros melampus) preference for burned areas was due to the increases in non‐N nutrients caused by burning. 5. These findings suggest that burned area attractiveness to herbivores is mainly driven by changes to forage quality and not potential decreases in predation risk caused by reductions in vegetation height. This article is protected by copyright. All rights reserved.
  • Predator avoidance during reproduction: diel movements by spawning sockeye
           salmon between stream and lake habitats
    • Abstract: 1. Daily movements of mobile organisms between habitats in response to changing trade‐offs between predation risk and foraging gains are well established; however, less in known about whether similar tactics are used during reproduction, a time period when many organisms are particularly vulnerable to predators. 2. We investigated the reproductive behaviour of adult sockeye salmon (Oncorhynchus nerka) and the activity of their principal predator, brown bears (Ursus arctos), on streams in southwestern Alaska. Specifically, we continuously monitored movements of salmon between lake habitat, where salmon are invulnerable to bears, and three small streams, where salmon spawn and are highly vulnerable to bears. We conducted our study across 2 years that offered a distinct contrast in bear activity and predation rates. 3. Diel movements by adult sockeye salmon between stream and lake habitat were observed in 51.3 ± 17.7% [mean ± SD] of individuals among years and sites. Fish that moved tended to hold in the lake for most of the day, and then migrated into spawning streams during the night coincident with when bear activity on streams tended to be lowest. Additionally, cyclic movements between lakes and spawning streams were concentrated earlier in the spawning season. 4. Individuals that exhibited diel movements had longer average reproductive life‐spans than those who made only one directed movement into a stream. However, the relative effect was dependent on the timing of bear predation, which varied between years. When predation pressure primarily occurred early in the spawning run (i.e., during the height of the diel movements), movers lived 120 – 310% longer than non‐movers. If predation pressure was concentrated later in the spawning run (i.e., when most movements had ceased), movers only lived 10‐60% longer. 5. Our results suggest a dynamic trade‐off in reproductive strategies of sockeye salmon; adults must be in the stream to reproduce, but must also avoid predation long enough to spawn. Given the inter‐annual variation in the timing and intensity of predation pressure, the advantages of a particular movement strategy will likely vary among years. Regardless, movements by salmon allowed individuals to exploit fine‐scale habitat heterogeneity during reproduction that appears to be a strategy to reduce predation risk on the spawning grounds. This article is protected by copyright. All rights reserved.
  • Community‐level Demographic Consequences of Urbanization: An
           Ecological Network Approach
    • Abstract: Ecological networks are known to influence ecosystem attributes, but we poorly understand how interspecific network structure affect population demography of multiple species, particularly for vertebrates. Establishing the link between network structure and demography is at the crux of being able to use networks to understand population dynamics and to inform conservation. We addressed the critical but unanswered question, does network structure explain demographic consequences of urbanization' We studied 141 ecological networks representing interactions between plants and nesting birds in forests across an urbanization gradient in Ohio, USA from 2001‐2011. Nest predators were identified by video‐recording nests and surveyed from 2004‐2011. As landscapes urbanized, bird‐plant networks were more nested, less compartmentalized, and dominated by strong interactions between a few species (i.e., low evenness). Evenness of interaction strengths promoted avian nest survival, and evenness explained demography better than urbanization, level of invasion, numbers of predators, or other qualitative network metrics. Highly uneven networks had approximately half the nesting success as the most even networks. Thus, nest survival reflected how urbanization altered species interactions, particularly with respect to how nest placement affected search efficiency of predators. The demographic effects of urbanization were not direct, but were filtered through bird‐plant networks. This study illustrates how network structure can influence demography at the community level, and further, that knowledge of species interactions and a network approach may be requisite to understanding demographic responses to environmental change. This article is protected by copyright. All rights reserved.
  • The smell of good food: volatile infochemicals as resource quality
    • Abstract: 1.Foraging success generally depends on various environmental and physiological factors. Particularly for organisms with limited motility such as gastropods, food searching is a very cost‐intensive process. As energy gain through foraging is dependent on both resource quality and quantity, consumers have to be able to differentiate between varying resource items. 2.The effectiveness of food searching could be increased through the perception of diet‐derived chemical signals that convey information about a food resource's quality over a certain distance. This strategy would clearly help to optimize movement decisions. 3.In this study, we investigated the foraging behaviour of a freshwater gastropod towards volatile signal substances released from benthic algae grown under high and low nutrient availability, representing high and low food quality, using behavioural assays in the laboratory. 4.Our results demonstrate that volatile organic compounds (VOCs) serve as foraging kairomones for these aquatic, benthic herbivores. Further, we were able to show for the first time that snails are able to differentiate between high and low quality food sources only by the perception of food odours alone (volatile infochemicals). 5.Gas chromatography coupled with mass spectrometry demonstrated quantitative as well as qualitative differences in the chemical composition of the VOC's bouquet, dependent on algal nutrient content. 6.Our results suggest that the recognition of resource quality via the reception of signal substances is likely to be adaptive for consumers with low mobility to maximize ingestion of high quality resources. This article is protected by copyright. All rights reserved.
  • A trophic cascade induced by predatory ants in a fig‐fig wasp
    • Abstract: 1.A trophic cascade occurs when predators directly decrease the densities, or change the behaviour, of herbivores and thus indirectly increase plant productivity. The predator‐herbivore‐plant context is well‐known, but some predators attack species beneficial to plants (e.g. pollinators) and/or enemies of herbivores (e.g. parasites) and their role in the dynamics of mutualisms remains largely unexplored. 2.We surveyed the predatory ant species and studied predation by the dominant ant species, the weaver ant Oecophylla smaragdina, associated with the fig tree Ficus racemosa in southwest China. We then tested the effects of weaver ants on the oviposition behaviour of pollinating and non‐pollinating fig wasps in an ant exclusion experiment. The effects of weaver ants on fig wasp community structure and fig seed production were then compared between trees with and without O. smaragdina. 3.Oecophylla smaragdina captured more non‐pollinating wasps (Platyneura mayri) than pollinators as the insects arrived to lay eggs. When ants were excluded, more non‐pollinators laid eggs into figs and fewer pollinators entered figs. Furthermore, trees with O. smaragdina produced more pollinator offspring and fewer non‐pollinator offspring, shifting the community structure significantly. In addition, F. racemosa produced significantly more seeds on trees inhabited by weaver ants. 4.Oecophylla smaragdina predation reverses the dominance of the two commonest wasp species at the egg‐laying stage, and favours the pollinators. This behavioural pattern is mirrored by wasp offspring production, with pollinators’ offspring dominating figs produced by trees inhabited by weaver ants, and offspring of the non‐pollinator P. mayri most abundant in figs on trees inhabited by other ants. 5.Overall, our results suggest that predation by weaver ants limits the success of the non‐pollinating P. mayri and therefore indirectly benefits the mutualism by increasing the reproductive success of both the pollinators and the plant. Predation is thus a key functional factor that can shape the community structure of a pollinator‐plant mutualistic system. This article is protected by copyright. All rights reserved.
  • Ectoparasitism and stress hormones: strategy of host exploitation, common
           host‐parasite history, and energetics matter
    • Abstract: 1. Parasites are thought to have numerous negative effects on their hosts. These negative effects may be associated with stress in a host. 2. We evaluated the effects of four species of flea ectoparasites (Parapulex chephrenis, Synosternus cleopatrae, Xenopsylla conformis and Xenopsylla ramesis) on non‐specific responses of eight species of rodents (Meriones crassus, Gerbillus dasyurus, Gerbillus andersoni, Gerbillus pyramidum, Gerbillus nanus, Acomys cahirinus, Acomys russatus and Mesocricetus auratus) and measured faecal glucocorticoid metabolites concentrations (FGMC) produced by the hosts. 3. We found no effect of body mass of an individual rodent on FGMCs. Parasitism by fleas with a “stay on the host body” exploitation strategy was associated with higher host FGMCs than parasitism by fleas that spent most of their life “off‐host”. FGMCs among rodents infested by the same flea species were correlated positively with the phylogenetic distance of a given rodent from the principal host of this flea; changes in FGMCs were lower in the host species more closely related to the flea's principal host. Changes in FMGCs of a host while parasitized were correlated with a host's change in body mass, where hosts that lost more body mass had higher FGMCs. 4. Our results suggest that ectoparasitism can be stressful to their hosts. However, the occurrence of parasite‐induced stress seems to depend on the identity of both host and parasite species and the evolutionary history of a host‐parasite association. To our knowledge, this is the first multi‐species study to evaluate the effect of ectoparasites on glucocorticoid hormones in small mammals. This article is protected by copyright. All rights reserved.
  • Let's go beyond taxonomy in diet description: testing a trait‐based
           approach to prey‐predator relationships
    • Abstract: 1. Understanding “Why a prey is a prey for a given predator'” can be facilitated through trait‐based approaches that identify linkages between prey and predator morphological and ecological characteristics and highlight key functions involved in prey selection. 2. Enhanced understanding of the functional relationships between predators and their prey is now essential to go beyond the traditional taxonomic framework of dietary studies, and to improve our knowledge of ecosystem functioning for wildlife conservation and management. 3. We test the relevance of a three‐matrix approach in foraging ecology among a marine mammal community in the north‐east Atlantic to identify the key functional traits shaping prey selection processes regardless of the taxonomy of both the predators and prey. 4. Our study reveals that prey found in the diet of marine mammals possess functional traits which are directly and significantly linked to predator characteristics, allowing the establishment of a functional typology of marine mammal‐prey relationships. We found prey selection of marine mammals was primarily shaped by physiological and morphological traits of both predators and prey, confirming that energetic costs of foraging strategies and muscular performance are major drivers of prey selection in marine mammals. 5. We demonstrate that trait‐based approaches can provide a new definition of the resource needs of predators. This framework can be used to anticipate bottom‐up effects on marine predator population dynamics, and to identify predators which are sensitive to the loss of key prey functional traits when prey availability is reduced. This article is protected by copyright. All rights reserved.
  • The marine diversity spectrum
    • Abstract: Distributions of species body sizes within a taxonomic group, for example, mammals, are widely studied and important because they help illuminate the evolutionary processes that produced these distributions. Distributions of the sizes of species within an assemblage delineated by geography instead of taxonomy (all the species in a region regardless of clade) are much less studied but are equally important and will illuminate a different set of ecological and evolutionary processes. We develop and test a mechanistic model of how diversity varies with body mass in marine ecosystems. The model predicts the form of the ‘diversity spectrum’, which quantifies the distribution of species' asymptotic body masses, is a species analogue of the classic size spectrum of individuals, and which we have found to be a new and widely applicable description of diversity patterns. The marine diversity spectrum is predicted to be approximately linear across an asymptotic mass range spanning seven orders of magnitude. Slope −0·5 is predicted for the global marine diversity spectrum for all combined pelagic zones of continental shelf seas, and slopes for large regions are predicted to lie between −0·5 and −0·1. Slopes of −0·5 and −0·1 represent markedly different communities: a slope of −0·5 depicts a 10‐fold reduction in diversity for every 100‐fold increase in asymptotic mass; a slope of −0·1 depicts a 1·6‐fold reduction. Steeper slopes are predicted for larger or colder regions, meaning fewer large species per small species for such regions. Predictions were largely validated by a global empirical analysis. Results explain for the first time a new and widespread phenomenon of biodiversity. Results have implications for estimating numbers of species of small asymptotic mass, where taxonomic inventories are far from complete. Results show that the relationship between diversity and body mass can be explained from the dependence of predation behaviour, dispersal, and life history on body mass, and a neutral assumption about speciation and extinction. This work demonstrates and explains for the first time a global phenomenon of how species diversity varies with body size in marine systems.
  • The role of social environment on parental care: offspring benefit more
           from the presence of female than male helpers
    • Abstract: Investment in offspring depends on the costs and benefits to the carer, which can vary with sex and social status. Investment also depends on the effort of others by allowing for compensation (load‐lightening), with biparental care studies showing that this depends on the state and type of the other carer. By contrast, studies on cooperative breeders have solely focussed on the effects of group size rather than its composition (i.e. social environment). Here we propose and provide the first test of the ‘Social Environment’ hypothesis, that is, how the characteristics (here the sex) of other helpers present in the group affect parental care and how this in turn affects offspring fitness in cooperatively breeding red‐winged fairy‐wrens (Malurus elegans). Breeders provisioned nestlings at a higher rate than helpers, but there was no sex difference in provisioning rate. Compensation to increasing group size varied little with sex and status, but strongly depended on social environment. All group members reduced their provisioning rates in response to an increasing number of male (load‐lightening), but not female helpers (additive care). As a result, nestlings received more food and grew faster in the presence of female helpers. The increased nestling growth did convey a fitness advantage due to a higher post‐fledging survival to adulthood. Our study provides the first evidence that parental care can depend on social environment. This could be an important overlooked aspect to explain variation in parental care in cooperative breeders in general and in particular the enormous variation between the sexes, which we reveal in a literature overview. Previous studies on parental care in cooperative breeders have focused on effects of group size on an individual's investment. Here the authors propose the ‘Social Environment’ hypothesis, which states that the type of helpers (specified by e.g. their sex or personality) present in the group will affect an individual's investment strategy.
  • When does diversity matter' Species functional diversity and ecosystem
           functioning across habitats and seasons in a field experiment
    • Abstract: Despite ample experimental evidence indicating that biodiversity might be an important driver of ecosystem processes, its role in the functioning of real ecosystems remains unclear. In particular, the understanding of which aspects of biodiversity are most important for ecosystem functioning, their importance relative to other biotic and abiotic drivers, and the circumstances under which biodiversity is most likely to influence functioning in nature, is limited. We conducted a field study that focussed on a guild of insect detritivores in streams, in which we quantified variation in the process of leaf decomposition across two habitats (riffles and pools) and two seasons (autumn and spring). The study was conducted in six streams, and the same locations were sampled in the two seasons. With the aid of structural equations modelling, we assessed spatiotemporal variation in the roles of three key biotic drivers in this process: functional diversity, quantified based on a species trait matrix, consumer density and biomass. Our models also accounted for variability related to different litter resources, and other sources of biotic and abiotic variability among streams. All three of our focal biotic drivers influenced leaf decomposition, but none was important in all habitats and seasons. Functional diversity had contrasting effects on decomposition between habitats and seasons. A positive relationship was observed in pool habitats in spring, associated with high trait dispersion, whereas a negative relationship was observed in riffle habitats during autumn. Our results demonstrate that functional biodiversity can be as significant for functioning in natural ecosystems as other important biotic drivers. In particular, variation in the role of functional diversity between seasons highlights the importance of fluctuations in the relative abundances of traits for ecosystem process rates in real ecosystems. This work greatly enhances our understanding of which aspects of biodiversity are most important for ecosystem functioning, what their importance relative to other biotic and abiotic drivers is, and the spatial and temporal circumstances under which biodiversity is most likely to influence functioning in nature.
  • Trophic niche width increases with bill‐size variation in a
           generalist passerine: a test of niche variation hypothesis
    • Abstract: The niche variation hypothesis (NVH) predicts that populations with wider niches are phenotypically more variable than populations with narrower niches, which is frequently used to explain diversifying processes such as ecological release. However, not all empirical evidence supports the NVH. Furthermore, a relationship between population phenotypic variation and niche width can be caused by sexual selection or environmental gradients, which should be carefully considered along with competition in explaining niche variation. In this study, we used eight populations of a generalist passerine species, Paradoxornis webbianus (vinous‐throated parrotbill), to test the NVH. We assessed evidence of ecological sexual dimorphism and environmental gradients in bill morphology of P. webbianus. A total of 170 P. webbianus from eight sites ranging 24–2668 m in altitude were included in this study. We used two principal components to quantify bill morphology: one describes bill size and the other describes bill slenderness. We used stable carbon and nitrogen isotope values of bird feathers to quantify trophic positions, and we estimated population trophic niche width using Bayesian standardized ellipse area. Paradoxornis webbianus with larger and more slender bills fed at higher trophic levels and population trophic niche width tended to increase with bill‐size variation, supporting the NVH. The males had larger bills and marginally higher nitrogen isotope values than the females, suggesting ecological sexual dimorphism. Despite a positive correlation between bill size and wing length indicating sexual selection for larger male size, only three of the eight populations showed both male‐biased bill size and male‐biased wing length. Sexual dimorphism explained 13%–64% of bill‐size variation across sites, suggesting its role in niche variation could vary greatly among populations. The variation in bill slenderness in P. webbianus increased with elevation. However, neither bill‐size variation nor trophic niche width changed with elevation. Therefore, environmental gradients that could be reflected in the elevation are not likely to drive the observed morphological and niche variation. This study provides an empirical case for the NVH and highlights the importance of investigating sexual dimorphism and environmental gradients in studies of niche dynamics. Using stable isotope values to quantify population trophic niche width, the authors demonstrate a novel way to test a classic evolutionary hypothesis, the niche variation hypothesis, in a generalist passerine. This approach has the potential to be widely applied to various taxa in a standardized way and can promote future meta‐analysis.
  • Adaptation of reproductive phenology to climate change with ecological
           feedback via dominance hierarchies
    • Abstract: Phenological shifts belong to the most commonly observed biological responses to recent climate change. It is, however, often unclear how these shifts are linked to demography and competitive interactions. We develop an eco‐evolutionary model to study adaptation of timing of reproduction in organisms with social dominance hierarchies. We focus on residential birds with winter flocks, where success in competition for territories among offspring depends on ranking given by prior residence. We study the effects of environmental change on breeding population densities, ensuing selection pressures and long‐term evolutionary equilibria. We consider changes in food peak date, in winter survival, in total reproductive output and in the width of the food distribution. We show that the evolutionarily stable hatching date will advance with increasing winter survival and reproductive output since these parameters increase habitat saturation and post‐fledging competition. Increasing the length of the breeding season also selects for earlier hatching date due to the reduced costs for producing offspring with high ranking. Our analysis shows that there is little correlation between short‐term and long‐term population responses across different scenarios of environmental change. However, short‐term population growth consistently predicts selection for earlier reproduction. Hence, the model identifies changed breeding population density as a key factor to understanding phenological adaptation in systems with prior residence advantages. While selection for change in reproductive phenology is often explained by changed seasonal variation in environmental variables, such as food abundance, we show that environmental change without apparent effects on seasonality can critically affect phenological adaptation. Such factors can mask or even override influences of changed seasonality on phenology. The model thus offers a conceptually new set of explanations for understanding phenological and demographic trends in a changing climate. By elucidating how dominance hierarchies and competitive interactions among offspring affect adaptation of timing of reproduction, the authors introduce a novel approach for interpreting phenological trends in species of a residential bird. This analysis also reveals new connections between demographic responses, phenological shifts and changes in winter survival and overall productivity.
  • Effects of exploitation on an overabundant species: the lesser snow goose
    • Abstract: Invasive and overabundant species are an increasing threat to biodiversity and ecosystem functioning world‐wide. As such, large amounts of money are spent each year on attempts to control them. These efforts can, however, be thwarted if exploitation is compensated demographically or if populations simply become too numerous for management to elicit an effective and rapid functional response. We examined the influence of these mechanisms on cause‐specific mortality in lesser snow geese using multistate capture–reencounter methods. The abundance and destructive foraging behaviours of snow geese have created a trophic cascade that reduces (sub‐) Arctic plant, insect and avian biodiversity, bestowing them the status of ‘overabundant’. Historically, juvenile snow geese suffered from density‐related degradation of their saltmarsh brood‐rearing habitat. This allowed harvest mortality to be partially compensated by non‐harvest mortality (process correlation between mortality sources: ρ = −0·47; 90% BCI: −0·72 to −0·04). Snow goose family groups eventually responded to their own degradation of habitat by dispersing to non‐degraded areas. This relaxed the pressure of density dependence on juvenile birds, but without this mechanism for compensation, harvest began to have an additive effect on overall mortality (ρ = 0·60; 90% BCI: −0·06 to 0·81). In adults, harvest had an additive effect on overall mortality throughout the 42‐year study (ρ = 0·24; 90% BCI: −0·59 to 0·67). With the aim of controlling overabundant snow geese, the Conservation Order amendment to the International Migratory Bird Treaty was implemented in February of 1999 to allow for harvest regulations that had not been allowed since the early 1900s (e.g. a spring harvest season, high or unlimited bag limits and use of electronic calls and unplugged shotguns). Although harvest mortality momentarily increased following these actions, the increasing abundance of snow geese has since induced a state of satiation in harvest that has driven harvest rates below the long‐term average. More aggressive actions will thus be needed to halt the growth and spread of the devastating trophic cascade that snow geese have triggered. Our approach to investigating the impacts of population control efforts on cause‐specific mortality will help guide more effective management of invasive and overabundant species world‐wide. Controlling invasive and overabundant species is of global economic and conservation importance. Here, Koons and colleagues provide a rigorous framework for evaluating the (in) effectiveness of population control efforts and utilizing science in an adaptive management framework on which more effective population control policies can be based. Photo by Lise Aubry.
  • Assessing sex‐related chick provisioning in greater flamingo
           Phoenicopterus roseus parents using capture–recapture models
    • Abstract: In sexually dimorphic species, the parental effort of the smaller sex may be reduced due to competitive exclusion in the feeding areas by the larger sex or physiological constraints. However, to determine gender effects on provisioning patterns, other intrinsic and extrinsic factors affecting parental effort should be accounted for. Greater flamingos (Phoenicopterus roseus) exhibit sexual size dimorphism. In Fuente de Piedra colony, the lake dries out almost completely during the breeding season and both parents commute between breeding and foraging sites >130 km away during the chick‐rearing period. Applying multistate capture–recapture models to daily observations of marked parents, we determined the effects of sex, and their interactions with other intrinsic and extrinsic factors, on the probability of chick desertion and sojourn in the colony and feeding areas. Moreover, using stable isotopes in the secretions that parents produce to feed their chicks, we evaluated sex‐specific use of wetlands. The probability of chick attendance (complementary to chick desertion) was >0·98. Chick desertion was independent of parental sex, but decreased with parental age. Females stayed in the feeding areas for shorter periods [mean: 7·5 (95% CI: 6·0–9·4) days] than males [9·2 (7·3–11·8) days]. Isotopic signatures of secretions did not show sex differences in δ13C, but males' secretions were enriched in δ15N, suggesting they fed on prey of higher trophic levels than females. Both parents spent approximately 1 day in the colony, but females prolonged their mean stay when the lake dried out. Females also allocated more time to foraging in the flooded areas remaining in the colony, likely because they were energetically more stressed than males. The results indicate that sex‐specific provisioning behaviour in greater flamingo is related to differential effects of both intrinsic and extrinsic factors. Males seem forage less efficiently than females, whereas females' body condition seems to be lower after feeding the chick. Our methodology may be extended to species that feed on distant food sources and that do not visit their offspring daily, to elucidate patterns of chick‐provisioning behaviour. By analysing resightings of individually marked flamingos, this study provides empirical evidence that capture‐recapture models can be successfully applied to estimate probabilities of desertion and commuting when parents do not visit their chicks daily and the marking of adults to track their movements (e.g. telemetry) is difficult.
  • Maternal, social and abiotic environmental effects on growth vary across
           life stages in a cooperative mammal
    • Abstract: Resource availability plays a key role in driving variation in somatic growth and body condition, and the factors determining access to resources vary considerably across life stages. Parents and carers may exert important influences in early life, when individuals are nutritionally dependent, with abiotic environmental effects having stronger influences later in development as individuals forage independently. Most studies have measured specific factors influencing growth across development or have compared relative influences of different factors within specific life stages. Such studies may not capture whether early‐life factors continue to have delayed effects at later stages, or whether social factors change when individuals become nutritionally independent and adults become competitors for, rather than providers of, food. Here, we examined variation in the influence of the abiotic, social and maternal environment on growth across life stages in a wild population of cooperatively breeding meerkats. Cooperatively breeding vertebrates are ideal for investigating environmental influences on growth. In addition to experiencing highly variable abiotic conditions, cooperative breeders are typified by heterogeneity both among breeders, with mothers varying in age and social status, and in the number of carers present. Recent rainfall had a consistently marked effect on growth across life stages, yet other seasonal terms only influenced growth during stages when individuals were growing fastest. Group size and maternal dominance status had positive effects on growth during the period of nutritional dependence on carers, but did not influence mass at emergence (at 1 month) or growth at independent stages (>4 months). Pups born to older mothers were lighter at 1 month of age and subsequently grew faster as subadults. Males grew faster than females during the juvenile and subadult stage only. Our findings demonstrate the complex ways in which the external environment influences development in a cooperative mammal. Individuals are most sensitive to social and maternal factors during the period of nutritional dependence on carers, whereas direct environmental effects are relatively more important later in development. Understanding the way in which environmental sensitivity varies across life stages is likely to be an important consideration in predicting trait responses to environmental change. This study uniquely compares abiotic, social and maternal factors affecting growth from birth until adulthood in a wild, cooperative mammal. Rain is important across all stages, whereas mothers and helpers influence growth most in early development. Understanding such complex environmental effects on development is important in a changing world.
  • Species versus guild level differentiation revealed across the annual
           cycle by isotopic niche examination
    • Abstract: Interspecific competitive interactions typically result in niche differentiation to alleviate competition through mechanisms including character displacement. However, competition is not the sole constraint on resource partitioning, and its effects are mediated by factors including the environmental context in which species coexist. Colonial seabirds provide an excellent opportunity to investigate the importance of competition in shaping realized niche widths because their life histories lead to variation in intra‐ and interspecific competition across the annual cycle. Dense breeding aggregations result in intense competition for prey in surrounding waters, whereas non‐breeding dispersal to larger geographical areas produces lower densities of competitors. Bayesian hierarchical models of the isotopic niche, closely aligned to the trophic niche, reveal the degree of segregation between species and functional groups during both time periods. Surprisingly, species explained far more of the variance in the isotopic niche during the non‐breeding than the breeding period. Our results underline the key role of non‐breeding dynamics in alleviating competition and promoting distinctions between species through the facilitation of resource partitioning. Such situations may be common in a diverse range of communities sustained by ephemeral but abundant food items. This highlights how consideration of the hierarchical grouping of competitive interactions alongside consideration of abiotic constraints across the complete annual cycle allows a full understanding of the role of competition in driving patterns of character displacement. This study highlights the key role of non‐breeding dynamics in alleviating competition and promoting distinctions between species through the facilitation of resource partitioning. Considering hierarchical competitive interactions alongside abiotic constraints across the complete annual cycle generates a fuller understanding of the role of competition in driving patterns of character displacement.
  • Viral antibody dynamics in a chiropteran host
    • Abstract: Bats host many viruses that are significant for human and domestic animal health, but the dynamics of these infections in their natural reservoir hosts remain poorly elucidated. In these, and other, systems, there is evidence that seasonal life‐cycle events drive infection dynamics, directly impacting the risk of exposure to spillover hosts. Understanding these dynamics improves our ability to predict zoonotic spillover from the reservoir hosts. To this end, we followed henipavirus antibody levels of >100 individual E. helvum in a closed, captive, breeding population over a 30‐month period, using a powerful novel antibody quantitation method. We demonstrate the presence of maternal antibodies in this system and accurately determine their longevity. We also present evidence of population‐level persistence of viral infection and demonstrate periods of increased horizontal virus transmission associated with the pregnancy/lactation period. The novel findings of infection persistence and the effect of pregnancy on viral transmission, as well as an accurate quantitation of chiropteran maternal antiviral antibody half‐life, provide fundamental baseline data for the continued study of viral infections in these important reservoir hosts. This is the first study of henipaviral infection dynamics in a fully closed population of the natural reservoir hosts. The authors detect population‐level infection persistence as well as increased periods of viral transmission related to life‐cycle events. These data help us to understand the seasonality of recurrent zoonotic spillovers of viruses from bat populations.
  • Dispersal in a patchy landscape reveals contrasting determinants of
           infection in a wild avian malaria system
    • Abstract: Understanding exactly when, where and how hosts become infected with parasites is critical to understanding host–parasite co‐evolution in natural populations. However, for host–parasite systems in which hosts or parasites are mobile, for example in vector‐borne diseases, the spatial location of infection and the relative importance of parasite exposure at successive host life‐history stages are often uncertain. Here, using a 6‐year longitudinal data set from a spatially referenced population of blue tits, we test the extent to which infection by avian malaria parasites is determined by conditions experienced at natal or breeding sites, as well as by postnatal dispersal between the two. We show that the location and timing of infection differs markedly between two sympatric malaria parasite species. For one species (Plasmodium circumflexum), our analyses indicate that infection occurs after birds have settled on breeding territories, and because the distribution of this parasite is temporally stable across years, hosts born in malarious areas could in principle alter their exposure and potentially avoid infection through postnatal dispersal. Conversely, the spatial distribution of another parasite species (Plasmodium relictum) is unpredictable and infection probability is positively associated with postnatal dispersal distance, potentially indicating that infection occurs during this major dispersal event. These findings suggest that hosts in this population may be subject to divergent selection pressures from these two parasites, potentially acting at different life‐history stages. Because this implies parasite species‐specific predictions for many coevolutionary processes, they also illustrate the complexity of predicting such processes in multi‐parasite systems. This study uses a novel approach to elucidate exactly when and where hosts become infected, for a vector‐borne disease system where hosts are highly mobile (avian malaria). The authors show that in a single host population, two parasite species infect hosts at different life‐history stages, leading to contrasting predictions about host–parasite coevolution.
  • Linking social and pathogen transmission networks using microbial genetics
           in giraffe (Giraffa camelopardalis)
    • Abstract: Although network analysis has drawn considerable attention as a promising tool for disease ecology, empirical research has been hindered by limitations in detecting the occurrence of pathogen transmission (who transmitted to whom) within social networks. Using a novel approach, we utilize the genetics of a diverse microbe, Escherichia coli, to infer where direct or indirect transmission has occurred and use these data to construct transmission networks for a wild giraffe population (Giraffe camelopardalis). Individuals were considered to be a part of the same transmission chain and were interlinked in the transmission network if they shared genetic subtypes of E. coli. By using microbial genetics to quantify who transmits to whom independently from the behavioural data on who is in contact with whom, we were able to directly investigate how the structure of contact networks influences the structure of the transmission network. To distinguish between the effects of social and environmental contact on transmission dynamics, the transmission network was compared with two separate contact networks defined from the behavioural data: a social network based on association patterns, and a spatial network based on patterns of home‐range overlap among individuals. We found that links in the transmission network were more likely to occur between individuals that were strongly linked in the social network. Furthermore, individuals that had more numerous connections or that occupied ‘bottleneck’ positions in the social network tended to occupy similar positions in the transmission network. No similar correlations were observed between the spatial and transmission networks. This indicates that an individual's social network position is predictive of transmission network position, which has implications for identifying individuals that function as super‐spreaders or transmission bottlenecks in the population. These results emphasize the importance of association patterns in understanding transmission dynamics, even for environmentally transmitted microbes like E. coli. This study is the first to use microbial genetics to construct and analyse transmission networks in a wildlife population and highlights the potential utility of an approach integrating microbial genetics with network analysis. This study utilizes a novel approach to quantify pathogen transmission patterns in wild giraffe. A transmission network was constructed by interlinking individuals if they shared genetic subtypes of Escherichia coli. This network was compared to networks representing giraffe social and spatial patterns. This integrative approach provides new insights about social dynamics in pathogen transmission.
  • A trade‐off between quantity and quality of offspring in
           haematophagous ectoparasites: the effect of the level of specialization
    • Abstract: Theory predicts an adaptive trade‐off between quantity and quality of offspring if mothers can reliably predict the offspring environment. We studied egg production and quality of offspring in two flea species (host‐specialist Parapulex chephrenis and host‐generalist Xenopsylla ramesis) exploiting eight rodent species. We evaluated quality of new imagoes via their developmental time, size (length of a femur as a proxy) and resistance to starvation without a blood meal. We predicted that the offspring quality would increase with (i) a decrease in the number of eggs produced by mothers and (ii) an increase in phylogenetic distance between maternal host and principal host of a flea. We also predicted that negative relationships between offspring quality and either maternal egg production effort or phylogenetic distance between maternal host and the principal host or both would be manifested stronger in host‐opportunistic than in host‐specific fleas. The highest number of eggs produced per female flea was accompanied by the longest duration of development and the smallest offspring in X. ramesis, while P. chephrenis that hatched from larger clutches survived for less time under starvation. Although there was no significant effect of host species on any dependent variable, association between offspring quality and phylogenetic distance of the maternal host from the principal host of a flea was found in X. ramesis (but not P. chephrenis) with new imagoes being larger if their maternal hosts were phylogenetically distant from the principal host. Our results demonstrated stronger trade‐off between quantity and quality of offspring in a generalist than in a specialist flea, supporting the association between life‐history plasticity and generalist feeding strategy. Here, the authors demonstrate, for the first time, that an occurrence of a trade‐off between quality and quantity of offspring in parasitic species depends on the level of specialization in feeding strategy.
  • Habitat‐former effects on prey behaviour increase predation and
           non‐predation mortality
    • Abstract: Habitat‐forming species can influence mortality on associated species via altering structural and non‐structural abiotic conditions. Importantly, these effects can occur simultaneously and in opposite directions, although how they contribute to the net outcomes for predator–prey interactions remain unexplored. Seagrasses often have positive effects on associated fauna because their structure directly reduces predator encounter rates. However, we identified a ‘risky’ behaviour (shallower burial) in an infaunal bivalve at a high seagrass cover – likely induced by non‐structural abiotic change – suggesting positive effects may be outweighed by risky behaviours. We determined whether the physical structure of the seagrass interacted with burial behaviour of clams to determine the predation and non‐predation mortality and whether these interactions were mediated by the cover of the seagrass. Surveys on an intertidal sand flat in Tasmania, Australia showed that the highest densities of a dominant bivalve, Katelysia scalarina, occurred at low (33%) seagrass cover, but the lowest densities and the highest proportion of unburied clams occurred at high (100%) cover. A field experiment manipulating burial depth, seagrass cover and predator access demonstrated that unburied clams suffered very high predation and non‐predation mortality compared to buried clams (~4x higher), which outweighed any positive effects of the seagrass structure in reducing predator access. Being unburied also had non‐lethal consequences with surviving unburied clams having a reduced tissue biomass compared to buried clams. In this system, predation was driven by the availability of prey when they undertake a risky behaviour (shallow burial). However, significant changes in behaviour may only occur once a threshold of habitat‐former density is reached. In this instance, changes in behaviour were likely due to seagrass effects on sediment redox potential, which decreased significantly above 33% seagrass cover. Our findings demonstrate that the negative effects of a habitat‐former on the behaviour of associated species, via alteration of non‐structural abiotic conditions, can outweigh any positive effects provided by increasing habitat structure as is commonly reported for habitat‐formers. Habitat‐forming species can simultaneously alter structural and non‐structural abiotic conditions that may act have opposing effects on associated prey species. Here the authors show that the negative effects of a habitat‐former on the behaviour of associated species, via non‐structural abiotic conditions, can outweigh positive effects provided by habitat‐structure.
  • Demographic responses of a site‐faithful and territorial predator to
           its fluctuating prey: long‐tailed skuas and arctic lemmings
    • Abstract: Environmental variability, through interannual variation in food availability or climatic variables, is usually detrimental to population growth. It can even select for constancy in key life‐history traits, though some exceptions are known. Changes in the level of environmental variability are therefore important to predict population growth or life‐history evolution. Recently, several cyclic vole and lemming populations have shown large dynamical changes that might affect the demography or life‐histories of rodent predators. Skuas constitute an important case study among rodent predators, because of their strongly saturating breeding productivity (they lay only two eggs) and high degree of site fidelity, in which they differ from nomadic predators raising large broods in good rodent years. This suggests that they cannot capitalize on lemming peaks to the same extent as nomadic predators and might be more vulnerable to collapses of rodent cycles. We develop a model for the population dynamics of long‐tailed skuas feeding on lemmings to assess the demographic consequences of such variable and non‐stationary prey dynamics, based on data collected in NE Greenland. The model shows that populations of long‐tailed skua sustain well changes in lemming dynamics, including temporary collapses (e.g. 10 years). A high floater‐to‐breeder ratio emerges from rigid territorial behaviour and a long‐life expectancy, which buffers the impact of adult abundance's decrease on the population reproductive output. The size of the floater compartment is affected by changes in both mean and coefficient of variation of lemming densities (but not cycle amplitude and periodicity per se). In Greenland, the average lemming density is below the threshold density required for successful breeding (including during normally cyclic periods). Due to Jensen's inequality, skuas therefore benefit from lemming variability; a positive effect of environmental variation. Long‐tailed skua populations are strongly adapted to fluctuating lemming populations, an instance of demographic lability in the reproduction rate. They are also little affected by poor lemming periods, if there are enough floaters, or juveniles disperse to neighbouring populations. The status of Greenland skua populations therefore strongly depends upon floater numbers and juvenile movements, which are not known. This reveals a need to intensify colour‐ringing efforts on the long‐tailed skua at a circumpolar scale. This paper highlights two current topics in populations dynamics: firstly, the importance of floater individuals, who are crucial here to population persistence, and secondly, positive effects of environmental variability, in contrast to usually negative effects. Photo: Long‐tailed skua pair, R.A. Ims.
  • The Lévy flight foraging hypothesis in a pelagic seabird
    • Abstract: Lévy flight foraging represents an innovative paradigm for the analysis of animal random search by including models of heavy‐tailed distribution of move length, which complements the correlated random walk paradigm that is founded on Brownian walks. Theory shows that the efficiency of the different foraging tactics is a function of prey abundance and dynamics with Lévy flight being especially efficient in poor prey fields. Lévy flights have been controversial in some quarters, because they previously have been wrongly ascribed to many species through the employment of inappropriate statistical techniques and by misunderstanding movement pattern data. More recent studies using state‐of‐the‐art statistical tools have, however, provided seemingly compelling evidence for Lévy flights. In this study, we employ these maximum‐likelihood methods and their Bayesian equivalents by analysing both turning angles and move length distributions. We tested, for compliance with Lévy flight foraging, a set of 77 independent foraging trajectories of Cory's shearwaters Calonectris diomedea diomedea. Birds were tagged with high‐resolution GPS loggers in two Mediterranean colonies (Linosa and Tremiti) during both incubation and chick rearing. We found that the behaviour of six birds was fitted by a correlated random walk; the movement of 32 birds was better represented by adaptive correlated random walks by switching from intensive to extensive searches; and the trajectories of 36 birds were fitted by a Lévy flight pattern of movement. The probability of performing Lévy flights was higher for trips during chick provisioning when shearwaters were forced to forage in suboptimal areas. This study supports Lévy flight foraging as an appropriate framework to analyse search tactics in this pelagic bird species and highlights that the adoption of a given search strategy is a function of biological and ecological constraints. There has recently been renewed debate about whether or not some sea birds have foraging patterns that are well represented by Lévy flights. This new study fills an important gap in the discussion by providing direct evidence for Lévy flights in the flight patterns of individual Cory's shearwaters. We show that Lévy flights are more likely when birds forage on poor prey field, near the colony.
  • Linking habitat selection and predation risk to spatial variation in
    • Abstract: A central assumption underlying the study of habitat selection is that selected habitats confer enhanced fitness. Unfortunately, this assumption is rarely tested, and in some systems, gradients of predation risk may more accurately characterize spatial variation in vital rates than gradients described by habitat selection studies. Here, we separately measured spatial patterns of both resource selection and predation risk and tested their relationships with a key demographic trait, adult female survival, for a threatened ungulate, woodland caribou (Rangifer tarandus caribou Gmelin). We also evaluated whether exposure to gradients in both predation risk and resource selection value was manifested temporally through instantaneous or seasonal effects on survival outcomes. We used Cox proportional hazards spatial survival modelling to assess the relative support for 5 selection‐ and risk‐based definitions of habitat quality, as quantified by woodland caribou adult female survival. These hypotheses included scenarios in which selection ideally mirrored survival, risk entirely drove survival, non‐ideal selection correlated with survival but with additive risk effects, an ecological trap with maladaptive selection and a non‐spatial effect of annual variation in weather. Indeed, we found positive relationships between the predicted values of a resource selection function (RSF) and survival, yet subsequently incorporating an additional negative effect of predation risk greatly improved models further. This revealed a positive, but non‐ideal relationship between selection and survival. Gradients in these covariates were also shown to affect individual survival probability at multiple temporal scales. Exposure to increased predation risk had a relatively instantaneous effect on survival outcomes, whereas variation in habitat suitability predicted by an RSF had both instantaneous and longer‐term seasonal effects on survival. Predation risk was an additive source of hazard beyond that detected through selection alone, and woodland caribou selection thus was shown to be non‐ideal. Furthermore, by combining spatial adult female survival models with herd‐specific estimates of recruitment in matrix population models, we estimated a spatially explicit landscape of population growth predictions for this endangered species. We show that spatial variation in woodland caribou survival correlates positively to resource selection models describing their behavior, but model selection also reveals an additive effect of wolf predation risk on survival. Thus, survival‐based depictions of habitat quality need account concurrently for spatial variation in both resource selection and predation risk.
  • Offspring size in a resident species affects community assembly
    • Abstract: Offspring size is a trait of fundamental importance that affects the ecology and evolution of a range of organisms. Despite the pervasive impact of offspring size for those offspring, the influence of offspring size on other species in the broader community remains unexplored. Such community‐wide effects of offspring size are likely, but they have not been anticipated by theory or explored empirically. For a marine invertebrate community, we manipulated the size and density of offspring of a resident species (Watersipora subtorquata) in the field and examined subsequent community assembly around that resident species. Communities that assembled around larger offspring were denser and less diverse than communities that assembled around smaller offspring. Differences in niche usage by colonies from smaller and larger offspring may be driving these community‐level effects. Our results suggest that offspring size is an important but unexplored source of ecological variation and that life‐history theory must accommodate the effects of offspring size on community assembly. Life‐history theory often assumes that environmental variation drives intraspecific variation in offspring size, and our results show that the converse can also occur. Here, the authors focus, for the first time, on the consequences of offspring size variation on community assembly. Their results raise the possibility that mothers can manipulate the environment that offspring experience.
  • Towards an energetic landscape: broad‐scale accelerometry in
           woodland caribou
    • Abstract: Energetic balance is a central driver of individual survival and population change, yet estimating energetic costs in free and wide ranging animals presents a significant challenge. Animal‐borne activity monitors (using accelerometer technology) present a promising method of meeting this challenge and opens new avenues for exploring energetics in natural settings. To determine the behaviours and estimated energetic costs associated with a given activity level, three captive reindeer (Rangifer tarandus tarandus) at the Toronto Zoo were fitted with collars and observed for 53 hours. Activity patterns were then measured over thirteen months for 131 free‐ranging woodland caribou (R. t. caribou) spanning 450,000 km2 in northern Ontario. The captive study revealed a positive but decelerating relationship between activity level and energetic costs inferred from previous behavioural studies. Field‐based measures of activity were modelled against individual displacement, vegetation abundance (NDVI), snow depth, and temperature, and the best fit model included all parameters and explained over half of the variation in the data. Individual displacement was positively related to activity levels, suggesting that broad differences in energetic demands are influenced by variation in movement rates. After accounting for displacement, activity was highest at intermediate levels of vegetation abundance, presumably due to foraging behaviour. Snow depth, probably associated with digging for winter forage, moderately increased activity. Activity levels increased significantly at the coldest winter temperatures, suggesting the use of behavioural thermoregulation by caribou. These interpretations of proximate causal factors should be regarded as hypotheses subject to validation under normal field conditions. These results illustrate the landscape characteristics that increase energetic demands for caribou and confirm the great potential for the use of accelerometry in studies of animal energetics. This article is protected by copyright. All rights reserved.
  • Inbreeding avoidance, patch isolation and matrix permeability influence
           dispersal and settlement choices by male agile antechinus in a fragmented
    • Abstract: Animal dispersal is highly non‐random and has important implications for the dynamics of populations in fragmented habitat. We identified interpatch dispersal events from genetic tagging, parentage analyses and assignment tests and modelled the factors associated with apparent emigration and post‐dispersal settlement choices by individual male agile antechinus (Antechinus agilis, a marsupial carnivore of south‐east Australian forests). Emigration decisions were best modelled with on data patch isolation and inbreeding risk. The choice of dispersal destination by males was influenced by inbreeding risk, female abundance, patch size, patch quality and matrix permeability (variation in land cover). Males were less likely to settle in patches without highly unrelated females. Our findings highlight the importance of individual‐level dispersal data for understanding how multiple processes drive non‐randomness in dispersal in modified landscapes. Fragmented landscapes present novel environmental, demographic and genetic contexts in which dispersal decisions are made, so the major factors affecting dispersal decisions in fragmented habitat may differ considerably from unfragmented landscapes. We show that the spatial scale of genetic neighbourhoods can be large in fragmented habitat, such that dispersing males can potentially settle in the presence of genetically similar females after moving considerable distances, thereby necessitating both a choice to emigrate and a choice of where to settle to avoid inbreeding. The authors use detailed data on individual dispersal events to test hypotheses about the factors influencing non‐randomness of dispersal in fragmented landscapes. They show that the avoidance of inbreeding has previously unappreciated effects on the ways in which animals move across natural landscapes, and in particular a strong effect on where individuals go after leaving home.
  • Does moonlight increase predation risk' Meta‐analysis reveals
           divergent responses of nocturnal mammals to lunar cycles
    • Abstract: The risk of predation strongly affects mammalian population dynamics and community interactions. Bright moonlight is widely believed to increase predation risk for nocturnal mammals by increasing the ability of predators to detect prey, but the potential for moonlight to increase detection of predators and the foraging efficiency of prey has largely been ignored. Studies have reported highly variable responses to moonlight among species, calling into question the assumption that moonlight increases risk. Here, we conducted a quantitative meta‐analysis examining the effects of moonlight on the activity of 59 nocturnal mammal species to test the assumption that moonlight increases predation risk. We examined patterns of lunarphilia and lunarphobia across species in relation to factors such as trophic level, habitat cover preference and visual acuity. Across all species included in the meta‐analysis, moonlight suppressed activity. The magnitude of suppression was similar to the presence of a predator in experimental studies of foraging rodents (13·6% and 18·7% suppression, respectively). Contrary to the expectation that moonlight increases predation risk for all prey species, however, moonlight effects were not clearly related to trophic level and were better explained by phylogenetic relatedness, visual acuity and habitat cover. Moonlight increased the activity of prey species that use vision as their primary sensory system and suppressed the activity of species that primarily use other senses (e.g. olfaction, echolocation), and suppression was strongest in open habitat types. Strong taxonomic patterns underlay these relationships: moonlight tended to increase primate activity, whereas it tended to suppress the activity of rodents, lagomorphs, bats and carnivores. These results indicate that visual acuity and habitat cover jointly moderate the effect of moonlight on predation risk, whereas trophic position has little effect. While the net effect of moonlight appears to increase predation risk for most nocturnal mammals, our results highlight the importance of sensory systems and phylogenetic history in determining the level of risk. Does moonlight increase predation risk' This meta‐analysis of nocturnal mammals finds that moonlight suppresses the activity of most species, indicating increased risk, but many prey species are more active with bright moonlight. Increased illumination may therefore benefit some prey through improved detection of predators and foraging efficiency.
  • Heterogeneous hosts: how variation in host size, behaviour, and immunity
           affect parasite aggregation in an experimental system
    • Abstract: 1.Infection heterogeneity is one of the most fundamental patterns in disease ecology, yet surprisingly few studies have experimentally explored its underlying drivers. Here, we used large‐scale field assessments to evaluate the degree of parasite aggregation within amphibian host populations followed by a novel experimental approach to assess the potential influence of host size, behaviour, and immunity in reproducing such heterogeneity. 2.Among 227 wetlands, 2,468 hosts, and 7 parasite species, infections were consistently aggregated among host individuals within populations of the Pacific chorus frog (Pseudacris regilla). For each parasite species, the relationship between the logmean and logvariance of infection load was strongly linear (R2: 0.91‐0.98) with a slope between 1.37 and 1.67, indicative of aggregation relative to the expected Poisson slope of unity. 3.In laboratory trials with P. regilla and the most virulent trematode (Ribeiroia ondatrae), experimental reductions of either host immunity (through corticosterone exposure) or anti‐parasite behaviours (through anesthesia exposure) increased parasite infection loads in isolated hosts by 62 to 102% relative to unmanipulated individuals. In a second experiment designed to test how variation in host immunity, behaviour and body size affected variation in infection load within small groups (dyads), a reduction in immune function or behaviour of one host significantly amplified infection heterogeneity within the group, effectively doubling the variance‐to‐mean ratio. However, immunity affected aggregation only in the absence of behavioural manipulation, and changing the size distribution of hosts did not appreciably affect aggregation. 4.Using Taylor's Power Law to integrate field and laboratory data, we found that only treatments involving behavioural reductions achieved aggregation levels comparable to natural host populations. Thus, despite their short duration, our treatments generated heterogeneity in infection loads similar to natural observations. 5.These results emphasize how, alongside extrinsic variation in parasite exposure risk, individual host attributes generally and behaviour in particular have the potential to influence infection success and parasite aggregation. Continued integration of infection heterogeneity research across space, among host species, and over time has important implications for understanding and managing human and wildlife diseases. This article is protected by copyright. All rights reserved.
  • Predictors of malaria infection in a wild bird population: Landscape level
           analyses reveal climatic and anthropogenic factors
    • Abstract: 1. How the environment influences the transmission and prevalence of disease in a population of hosts is a key aspect of disease ecology. The role that environmental factors play in host‐pathogen systems has been well studied at large scales, i.e. differences in pathogen pressures among separate populations of hosts, or across land masses. However, despite considerable understanding of how environmental conditions vary at fine spatial scales, the effect of these parameters on host‐pathogen dynamics at such scales has been largely overlooked. 2. Here we used a combination of molecular screening and GIS‐based analysis to investigate how environmental factors determine the distribution of malaria across the landscape in a population of Berthelot's pipit (Anthus berthelotii, Bolle 1862) on the island of Tenerife (Canary Islands, Spain) using spatially explicit models that account for spatial autocorrelation. 3. Minimum temperature of the coldest month was found to be the most important predictor of malaria infection at the landscape scale across this population. Additionally, anthropogenic factors such as distance to artificial water reservoirs and distance to poultry farms were important predictors of malaria. A model including these factors, and the interaction between distance to artificial water reservoirs and minimum temperature, best explained the distribution of malaria infection in this system. 4. These results suggest that levels of malaria infection in this endemic species may be artificially elevated by the impact of humans. 5. Studies such as the one described here improve our understanding of how environmental factors, and their heterogeneity, affect the distribution of pathogens within wild populations. The results demonstrate the importance of measuring fine scale variation ‐ and not just regional effects ‐ in order to understand how environmental variation can influence wildlife diseases. Such understanding is important for predicting the future spread and impact of disease and may help inform disease management programmes as well as the conservation of specific host species. This article is protected by copyright. All rights reserved.
  • An evolutionary perspective on reproductive individual heterogeneity in a
           marine vertebrate
    • Abstract: 1.Although the quantification of individual heterogeneity in wild populations’ vital rates has recently attracted growing interest among ecologists, the investigation of its evolutionary consequences remains limited, mainly because of the difficulties in assessing fitness and heritability from field studies on free‐ranging animals. In the presence of individual variability, evaluation of fitness consequences can notably be complicated by the existence of trade‐offs among different vital rates. 2.In this study, to further assess the evolutionary significance of previously quantified levels of individual heterogeneity in female Weddell seal (Leptonychotes weddellii Lesson) reproductive rates (Chambert et al. 2013), we investigated how several life history characteristics of female offspring were related to their mother's reproductive rate, as well as to other maternal traits (age and experience) and environmental conditions at birth. 3.The probability and age of first reproduction (recruitment) of female offspring was not related to their mother's reproductive rate, suggesting the absence of a maternal trade‐off between the number and quality of offspring a female produces. Evidence of a positive, but relatively weak, relationship between the reproductive rates of a mother and her female offspring was found, suggesting some degree of heritability in this trait. 4.Using a simulation approach based on these statistical findings, we showed that substantial differences in the number of grandchildren, produced through female progeny can be expected among females with different reproductive rates. 5.Despite the presence of substantial stochastic variability, due to environmental fluctuations and other unidentified mechanisms, and in light of the fact that the metrics obtained do not provide a full measure of real fitness, our results do suggest that the individual reproductive variability found in female Weddell seals could potentially have important fitness consequences.
  • Life‐history diversity and its importance to population stability
           and persistence of a migratory fish: steelhead in two large North American
    • Abstract: 1.Life‐history strategies can buffer individuals and populations from environmental variability. For instance, it is possible that asynchronous dynamics among different life‐histories can stabilize populations through portfolio effects. 2.Here we examine life‐history diversity and its importance to stability for an iconic migratory fish species. In particular, we examined steelhead (Oncorhynchus mykiss), an anadromous and iteroparous salmonid, in two large, relatively pristine, watersheds, the Skeena and Nass, in northwestern British Columbia, Canada. We synthesized life‐history information derived from scales collected from adult steelhead (N = 7227) in these watersheds across a decade. 3.These migratory fishes expressed 36 different manifestations of the anadromous life‐history strategy, with 16 different combinations of freshwater and marine ages, 7.6% of fish performing multiple spawning migrations, and up to 4 spawning migrations. Furthermore, in the Nass watershed, different life‐histories were differently prevalent through time—three different life‐histories were the most prevalent in a given year and no life‐history ever represented more than 45% of the population. These asynchronous dynamics among life‐histories decreased the variability of numerical abundance and biomass of the aggregated population so that it was more than 20% more stable than the stability of the weighted average of specific life‐histories, evidence of a substantial portfolio effect. Year of ocean entry was a key driver of dynamics; the median correlation coefficient of abundance of life‐histories that entered the ocean the same year was 2.5 times higher than the median pairwise coefficient of life‐histories that entered the ocean at different times. Simulations illustrated how different elements of life‐history diversity contribute to stability and persistence of populations. 4.This study provides evidence that life‐history diversity can dampen fluctuations in population abundances and biomass via portfolio effects. Conserving genetic integrity and habitat diversity in this and other large watersheds can enable a diversity of life‐histories that increases stability to environmental variability. This article is protected by copyright. All rights reserved.
  • Dispersal‐mediated effect of microhabitat availability and density
           dependence determine population dynamics of a forest‐floor web
    • Abstract: 1.Landscapes in nature can be viewed as a continuum of small total habitable area with high fragmentation to widely spreading habitats. The dispersal‐mediated rescue effect predominates in the former landscapes, while classical density‐dependent processes generally prevail in widely spread habitats. A similar principle should be applied to populations of organisms utilizing microhabitats in limited supply. 2.To test this hypothesis, we examined the population dynamics of a web spider, Neriene brongersmai, in 16 populations with varying degrees of microhabitat availability, and we explored whether: (1) high microhabitat availability improves survival rate during density‐independent movement, while the resultant high density reduces survival rate in a density‐dependent manner; and (2) temporal population stability increases with microhabitat availability at the population level. Furthermore, we conducted two types of field experiments to verify whether high microhabitat availability actually reduces mortality associated with web‐site movement. 3.Field observations revealed that demographic change in N. brongersmai populations was affected by three factors at different stages, namely, the microhabitat limitation from the early to late juvenile stages, the density dependence from the late juvenile to adult stages, and the food limitation from the adult to the next early juvenile stages. In addition, there was a tendency for a positive association between population stability and microhabitat availability at the population level. 4.A small‐scale experiment, where the frequency of spider web relocation was equalized artificially, revealed that high microhabitat availability elevated the survival rate during a movement event between web‐sites. The larger spatiotemporal scale experiment also revealed an improved spider survival rate following treatment with high microhabitat availability, even though spider density was kept at a relatively low level. 5.The population dynamics of N. brongersmai can be determined primarily by density‐independent processes based on web‐site fragmentation and density‐dependent processes driven by interference competition. We conclude that, depending on the amount of habitat resources, the relative importance of the two contrasting paradigms—equilibrium and non‐equilibrium—appears to vary, even within a particular system. This article is protected by copyright. All rights reserved.
  • Individual and sex‐specific differences in intrinsic growth rate
           covary with consistent individual differences in behaviour
    • Abstract: 1.The evolutionary causes of consistent individual differences in behavior are currently a source of debate. A recent hypothesis suggests that consistent individual differences in life‐history productivity (growth and/or fecundity) may covary with behavioral traits that contribute to growth‐mortality trade‐offs, such as risk‐proneness (boldness) and foraging activity (voraciousness). It remains unclear, however, to what extent individual behavioral and life‐history profiles are set early in life, or are a more flexible result of specific environmental or developmental contexts that allow bold and active individuals to acquire more resources. 2.Longitudinal studies of individually housed animals under controlled conditions can shed light on this question. Since growth and behaviour can both vary within individuals (they are labile), studying between‐individual correlations in behaviour and growth rate requires repeated scoring for both variables over an extended period of time. However, such a study has not yet been done. 3.Here, we repeatedly measured individual mass 7‐times each, boldness 40‐times each, and voracity 8‐times each during the first four months of life on 90 individually‐housed crayfish (Cherax destructor). Animals were fed ad‐libitum, generating a context where individuals can express their intrinsic growth rate (i.e. growth capacity), but in which bold and voracious behaviour is not necessary for high resource acquisition (crayfish can and do hoard food back to their burrow). 4.We show that individuals that were consistently bold over time during the day were also bolder at night, were more voracious, and maintained higher growth rates over time than shy individuals. Independent of individual differences, we also observed that males were faster growing, bolder, and more voracious than females. 5.Our findings imply that associations between bold behaviour and fast growth can occur in unlimited food contexts where there is no necessary link between bold behaviour and resource acquisition – offering support for the ‘personality‐ productivity’ hypothesis. We suggest future research should study links between consistent individual differences in behaviour and life‐history under a wider range of contexts, in order to shed light on the role of biotic and abiotic conditions in the strength, direction and stability of their covariance. This article is protected by copyright. All rights reserved.
  • Ecological opportunities and intraspecific competition alter trophic niche
           specialization in an opportunistic stream predator
    • Abstract: Many generalist populations are composed of specialized individuals that use a narrow part of the population's niche. Ecological theories predict that individual specialization and population trophic niche are determined by biotic interactions and resource diversity emerging from environmental variations (i.e., ecological opportunities). However, due to the paucity of empirical and experimental demonstrations, the genuine importance of each of these drivers in determining trophic niche attributes is not fully appreciated. The present study aimed at determining the population level and individual responses of brown trout (Salmo trutta) to variations in ecological opportunities (terrestrial prey inputs) and autochthonous prey communities among ten stream reaches along a riparian condition gradient using individual longitudinal monitoring and stable isotope analyses. Our results suggested that trophic niche diversity varied along the environmental gradient while individual trophic specialization was indirectly driven by ecological opportunities through strengthened intraspecific competition. Individual diet was repeatable over the study period and the growth rate of juvenile brown trout increased with their specialization for aquatic predatory invertebrates. Our findings highlight the dual influences of intraspecific competition and ecological opportunities on individual trophic specialization and trophic niche construction. This article is protected by copyright. All rights reserved.
  • Habitat degradation is threatening reef replenishment by making fish
    • Abstract: Habitat degradation is one of the “Big Five” drivers of biodiversity loss. However, the mechanisms responsible for this progressive loss of biodiversity are poorly understood. In marine ecosystems, corals play the role of ecosystem engineers, providing essential habitat for hundreds of species and hence their health is crucial to the stability of the whole ecosystem. Climate change is causing coral bleaching and degradation, and while this has been known for a while, little do we know about the cascading consequences of these events on the complex interrelationships between predators and their prey. The goal of our study was to investigate, under completely natural conditions, the effect of coral degradation on predator‐prey interactions. Settlement‐stage ambon damselfish (Pomacentrus amboinensis), a common tropical fish, were released on patches of healthy or dead corals, and their behaviours in situ were measured, along with their response to injured conspecific cues, a common risk indicator. This study also explored the effect of habitat degradation on natural levels of mortality at a critical life history transition. We found that juveniles in dead corals displayed risk‐prone behaviours, sitting further away and higher up on the reef patch, and failed to respond to predation cues, compared to those on live coral patches. In addition, in situ survival experiments over 48 hrs indicated that juveniles on dead coral habitats had a 75% increase in predation‐related mortality, compared to fish released on live, healthy coral habitats. Our results provide the first of many potential mechanisms through which habitat degradation can impact the relationship between prey and predators in the coral reef ecosystem. As the proportion of dead coral increases, the recruitment and replenishment of coral reef fishes will be threatened, and so will the level of diversity in these biodiversity hotspots. This article is protected by copyright. All rights reserved.
  • Frequent and seasonally variable sublethal anthrax infections are
           accompanied by short‐lived immunity in an endemic system
    • Abstract: 1. Few studies have examined host‐pathogen interactions in wildlife from an immunological perspective, particularly in the context of seasonal and longitudinal dynamics. In addition, though most ecological immunology studies employ serological antibody assays, endpoint titer determination is usually based on subjective criteria and needs to be made more objective. 2. Despite the fact that anthrax is an ancient and emerging zoonotic infectious disease found worldwide, its natural ecology is not well understood. In particular, little is known about the adaptive immune responses of wild herbivore hosts against Bacillus anthracis. 3. Working in the natural anthrax system of Etosha National Park, Namibia, we collected 154 serum samples from plains zebra (Equus quagga), 21 from springbok (Antidorcas marsupialis), and 45 from African elephants (Loxodonta africana) over 2‐3 years, resampling individuals when possible for seasonal and longitudinal comparisons. We used enzyme‐linked immunosorbent assays to measure anti‐anthrax antibody titers and developed three increasingly conservative models to determine endpoint titers with more rigorous, objective mensuration. 4. Between 52‐87% of zebra, 0‐15% of springbok, and 3‐52% of elephants had measurable anti‐anthrax antibody titers, depending on the model used. While the ability of elephants and springbok to mount anti‐anthrax adaptive immune responses is still equivocal, our results indicate that zebra in ENP often survive sublethal anthrax infections, encounter most B. anthracis in the wet season, and can partially booster their immunity to B. anthracis. 5. Thus, rather than being solely a lethal disease, anthrax often occurs as a sublethal infection in some susceptible hosts. Though we found that adaptive immunity to anthrax wanes rapidly, subsequent and frequent sublethal B. anthracis infections cause maturation of anti‐anthrax immunity. By triggering host immune responses, these common sublethal infections may act as immunomodulators and affect population dynamics through indirect immunological and co‐infection effects. 6. In addition, with our three endpoint titer models, we introduce more mensuration rigor into serological antibody assays, even under the often‐restrictive conditions that come with adapting laboratory immunology methods to wild systems. With these methods we identified significantly more zebras responding immunologically to anthrax than have previous studies using less comprehensive titer analyses. This article is protected by copyright. All rights reserved.
  • Immigrants are attracted by local pre‐breeders and recruits in a
           seabird colony
    • Abstract: 1.Immigration is a major demographic factor shaping population dynamics. However, due to methodological difficulties, the extent of immigration and factors affecting immigration are insufficiently studied. This is also true for seabird colonies. 2.We estimated annual immigration based on a long‐term study of a colony of common terns Sterna hirundo marked with transponders, using a Bayesian integrated population model that links colony size and productivity with individual life histories. 3.Strong annual fluctuations in the number of immigrants were found. In order to identify whether colony‐specific covariates influenced immigration, we related the number of immigrants to various proxy variables for breeding site quality, specifically colony size, productivity, number of local subadults and local recruits. Numbers of local recruits and local subadults showed strong positive correlations with number of immigrants. 4.We found that variation in immigration rate had strongly contributed to variation in colony growth rate, more so than variation in local recruitment or adult survival. 5.Collectively, results suggest that immigration strongly affects colony growth rate, that the driving force behind immigration is natal dispersal and that immigrants were attracted by local recruits. This article is protected by copyright. All rights reserved.
  • Linking phenological shifts to species interactions through
           size‐mediated priority effects
    • Abstract: 1.Inter‐annual variation in seasonal weather patterns causes shifts in the relative timing of phenological events of species within communities, but we currently lack a mechanistic understanding of how these phenological shifts affect species interactions. Identifying these mechanisms is critical to predicting how inter‐annual variation affects populations and communities. 2.Species’ phenologies, particularly the timing of offspring arrival, play an important role in the annual cycles of community assembly. We hypothesize that shifts in relative arrival of offspring can alter interspecific interactions through a mechanism called size‐mediated priority effects (SMPE), in which individuals that arrive earlier can grow to achieve a body size advantage over those that arrive later. 3.In this study, we used an experimental approach to isolate and quantify the importance of SMPE for species interactions. Specifically, we simulated shifts in relative arrival of the nymphs of two dragonfly species to determine the consequences for their interactions as intraguild predators. 4.We found that shifts in relative arrival altered not only predation strength but also the nature of predator‐prey interactions. When arrival differences were great, SMPE allowed the early arriver to prey intensely upon the late arriver, causing exclusion of the late arriver from nearly all habitats. As arrival differences decreased, the early arriver's size advantage also decreased. When arrival differences were smallest, there was mutual predation, and the two species coexisted in similar abundances across habitats. Importantly, we also found a nonlinear scaling relationship between shifts in relative arrival and predation strength. Specifically, small shifts in relative arrival caused large changes in predation strength while subsequent changes had relatively minor effects. 5.These results demonstrate that SMPE can alter not only the outcome of interactions but also the demographic rates of species and the structure of communities. Elucidating the mechanisms that link phenological shifts to species interactions is crucial for understanding the dynamics of seasonal communities as well as for predicting the effects of climate change on these communities. This article is protected by copyright. All rights reserved.
  • Greater migratory propensity in hosts lowers pathogen transmission and
    • Abstract: 1.Animal migrations are spectacular and migratory species have been shown to transmit pathogens that pose risks to human health. Although migration is commonly assumed to enhance pathogen dispersal, empirical work indicates that migration can often have the opposite effect of lowering disease risk. 2.Key to assessing disease threats to migratory species is the ability to predict how migratory behaviour influences pathogen invasion success and impacts on migratory hosts, thus motivating a mechanistic understanding of migratory host‐pathogen interactions. 3.Here we develop a quantitative framework to examine pathogen transmission in animals that undergo two‐way directed migrations between wintering and breeding grounds annually. 4.Using the case of a pathogen transmitted during the hosts’ breeding season, we show that a more extreme migratory strategy (defined by the time spent away from the breeding site and the total distance migrated) lowers the probability of pathogen invasion. Moreover, if migration substantially lowers the survival probability of infected animals, then populations that spend comparatively less time at the breeding site or that migrate longer distances are less vulnerable to pathogen‐induced population declines. 5.These findings provide theoretical support for two non‐exclusive mechanisms proposed to explain how seasonal migration can lower infection risk: (i) escape from habitats where parasite transmission stages have accumulated, and (ii) selective removal of infected hosts during strenuous journeys. Our work further suggests that barriers to long distance movement could increase pathogen prevalence for vulnerable species, an effect already seen in some animal species undergoing anthropogenically induced migratory shifts. This article is protected by copyright. All rights reserved.
  • Using dynamic Brownian bridge movement modeling to measure temporal
           patterns of habitat selection
    • Abstract: 1.Accurately describing animal space use is vital to understanding how wildlife use habitat. Improvements in GPS technology continue to facilitate collection of telemetry data at high spatial and temporal resolutions. Application of the recently introduced dynamic Brownian bridge movement model (dBBMM) to such data is promising as the method explicitly incorporates the behavioural heterogeneity of a movement path into the estimated utilization distribution (UD). 2.Utilization distributions defining space use are normally estimated for time scales ranging from weeks to months, obscuring much of the fine scale information available from high volume GPS data sets. By accounting for movement heterogeneity, the dBBMM provides a rigorous, behaviourally‐based estimate of space use between each set of relocations. Focusing on UDs generated between individual sets of locations allows us to quantify fine scale circadian variation in habitat use. 3.We used the dBBMM to estimate UDs bounding individual time steps for three terrestrial species with different life histories to illustrate how the method can be used to identify fine scale variations in habitat use. We also demonstrate how dBBMM's can be used to characterize circadian patterns of habitat selection and link fine‐scale patterns of habitat use to behaviour. 4.We observed circadian patterns of habitat use that varied seasonally for a white‐tailed deer (Odocoileus virginianus) and coyote (Canis latrans). We found seasonal patterns in selection by the white‐tailed deer, and were able to link use of conifer forests and agricultural fields to behavioural state of the coyote. Additionally, we were able to quantify the date in which a Rio Grande wild turkey (Meleagris gallopavo intermedia) initiated laying as well as when during the day she was most likely to visit the nest site to deposit eggs. 5.The ability to quantify circadian patterns of habitat use may have important implications for research and management of wildlife. Additionally, the ability to link such patterns to behaviour may aid in the development of mechanistic models of habitat selection. This article is protected by copyright. All rights reserved.
  • Evidence of localized resource depletion following a natural colonization
           event by a large marine predator
    • Abstract: 1.For central place foragers, forming colonies can lead to extensive competition for prey around breeding areas and a zone of local prey depletion. As populations grow, this area of reduced prey can expand impacting foraging success and forcing animals to alter foraging behaviour. 2.Here, we examine a population of marine predators, the northern fur seal (Callorhinus ursinus), which colonized a recently formed volcanic island, and assess changes in foraging behaviour associated with increasing population density. Specifically, we measured pup production and adult foraging behaviour over a 15‐year period, during which the population increased 4‐fold. 3.Using measures of at‐sea movements and dive behaviour, we found clear evidence that as the population expanded animals were required to allot increasing effort to obtain resources. These changes in behaviour included longer duration foraging trips, farther distances travelled, a larger foraging range surrounding the island, and deeper maximum dives. 4.Our results suggest that as the northern fur seal population increased, local prey resources were depleted as a result of increased intraspecific competition. In addition, the recent slowing of population growth indicates that this population may be approaching carrying capacity just 31 years after a natural colonization event. 5.Our study offers insight into the dynamics of population growth and impacts of increasing population density on a large marine predator. Such data could be vital for understanding future population fluctuations that occur in response to the dynamic environment, as natural and anthropogenic factors continue to modify marine habitats. This article is protected by copyright. All rights reserved.
  • Behavioral and physiological responses of limpet prey to a seastar
           predator and their transmission to basal trophic levels
    • Abstract: Besides the well documented behavioral changes induced by predators on prey, the predator‐induced stress can also include a suite of biochemical, neurological and metabolic changes that may represent important energetic costs and have long‐lasting effects on individuals and on the demography of prey populations. The rapid transmission of prey behavioral changes to lower trophic levels, usually associated to alteration of feeding rates, can substantially change and even reverse direction over the long term as prey cope with the energetic costs associated to predation‐induced stress. It is therefore critical to evaluate different aspects and assess the costs of non‐consumptive predator effects on prey. We investigated the behavioral and physiological responses of an herbivorous limpet, Fissurella limbata, to the presence of chemical cues and direct non‐lethal contact by the common seastar predator, Heliaster helianthus. We also evaluated whether the limpets feeding behavior was modified by the predator and whether this translated into positive or negative effects on biomass of the green alga, Ulva sp. Our experimental results show the presence of Heliaster led to increased movement activity, increased distances travelled, changes in time budget over different environmental conditions, and increased feeding rate in the keyhole limpets. Moreover, additional experiments showed that, beyond the increased metabolic rate associated to limpet increased activity, predator chemical cues heighten metabolic rate as part of the induced stress response. Changes in individual movement and displacement distances observed through the 9d experiment can be interpreted as part of the escape response exhibited by limpets to reduce the risk of being captured by the predator. Increased limpet feeding rate on algae can be visualized as a way individuals compensate for the elevated energetic costs of movement and heightened metabolic rates produced by the predator‐induced stress, which can leads to negative effects on abundance of the lower trophic level. This article is protected by copyright. All rights reserved.
  • A critical examination of indices of dynamic interaction for wildlife
           telemetry studies
    • Abstract: Wildlife scientists continue to be interested in studying ways to quantify how the movements of animals are inter‐dependent – dynamic interaction. While a number of applied studies of dynamic interaction exist, little is known about the comparative effectiveness and applicability of available methods used for quantifying interactions among animals. We highlight the formulation, implementation, and interpretation of a suite of eight currently available indices of dynamic interaction. Point‐ and path‐based approaches are contrasted to demonstrate differences between methods and underlying assumptions on telemetry data. Correlated and biased‐correlated random walks were simulated at a range of sampling resolutions to generate scenarios with dynamic interaction present and absent. We evaluate the effectiveness of each index at identifying differing types of interactive behaviour at each sampling resolution. Each index is then applied to an empirical telemetry dataset of three white‐tailed deer (Odocoileus virginianus) dyads. Results from the simulated data show that three indices of dynamic interaction reliant on statistical testing procedures are susceptible to Type I error, which increases at fine sampling resolutions. In the white‐tailed deer examples, a recently developed index for quantifying local‐level cohesive movement behaviour (the di index) provides revealing information on the presence of infrequent and varying interactions in space and time. Point‐based approaches implemented with finely sampled telemetry data over‐estimate the presence of interactions (Type I errors). Indices producing only a single global statistic (7 of the 8 indices) are unable to quantify infrequent and varying interactions through time. The quantification of infrequent and variable interactive behaviour has important implications for the spread of disease, and the prevalence of social behaviour in wildlife. Guidelines are presented to inform researchers wishing to study dynamic interaction patterns in their own telemetry datasets. Finally, we make openly available our code, in the statistical software R, for computing each index of dynamic interaction presented herein. This article is protected by copyright. All rights reserved.
  • Accounting for individual behavioural variation in studies of habitat
    • Abstract: Resource selection is often assumed to confer enhanced fitness, but this assumption is rarely examined. In a study involving woodland caribou subject to gray wolf predation, DeCesare et al. (2014) show that while patterns of selection by caribou did correspond with a fitness proxy (survival probability), individuals did not avoid wolf predation risk to the extent that would minimize mortality. Here, we use the results of this paper as a springboard for discussing choice of fitness proxies and the need to account for individual behavioral variation in studies of resource selection. This article is protected by copyright. All rights reserved.
  • Large‐scale movements in European badgers: has the tail of the
           movement kernel been underestimated'
    • Abstract: Characterising patterns of animal movement is a major aim in population ecology, and yet doing so at an appropriate spatial‐scale remains a major challenge. Estimating the frequency and distances of movements are of particular importance when species are implicated in the transmission of zoonotic diseases. European badgers (Meles meles) are classically viewed as exhibiting limited dispersal, and yet their movements bring them into conflict with farmers due to their potential to spread bovine tuberculosis in parts of their range. Considerable uncertainty surrounds the movement potential of badgers, and this may be related to the spatial‐scale of previous empirical studies. We conducted a large‐scale mark‐recapture study on badgers (755km2; 2008‐2012; 1,935 capture‐events; 963 badgers) to investigate movement patterns in badgers, and undertook a comparative meta‐analysis using published data from 15 European populations. The dispersal movement (>1km) kernel followed an inverse power‐law function, with a substantial ‘tail’ indicating the occurrence of rare long‐distance dispersal attempts during the study period. The mean recorded distance from this distribution was 2.6km., the upper 95%ile was 7.3km and the longest recorded was 22.1km. Dispersal frequency distributions were significantly different between genders; males dispersed more frequently than females but females made proportionally more long‐distance dispersal attempts than males. We used a subsampling approach to demonstrate that the appropriate minimum spatial‐scale to characterise badger movements in our study population was 80km2, substantially larger than many previous badger studies. Furthermore, the meta‐analysis indicated a significant association between maximum movement distance and study area size, while controlling for population density. Maximum long‐distance movements were often only recorded by chance beyond the boundaries of study areas. These findings suggest that the tail of the badger movement distribution is currently underestimated. The implications of this for understanding the spatial‐ecology of badger populations and for the design of disease intervention strategies are potentially significant. This article is protected by copyright. All rights reserved.
  • Night warming on hot days produces novel impacts on development, survival
           and reproduction in a small arthropod
    • Abstract: An asymmetric increase of nighttime temperatures on hot days is one of the main features of global climate change. But the biological effects of an increased nighttime temperature combined with high daytime temperature are unclear. We used six thermal regimens to simulate nighttime temperatures on hot days and investigated the effects of night warming on life history traits of the English grain aphid Sitobion avenae. Experimental temperatures fluctuated in continuous diurnal cycles, increasing from 27 °C to a maximum 35 °C and then declining to 27 °C gradually before further dropping to different minima (13, 16, 19, 21, 23 or 25 °C) representing nighttime temperatures. When compared to expectations based on constant temperatures, night warming raised the optimum temperature for development by 3 °C, in contrast to results from experiments where temperature variability was altered symmetrically or in a parallel manner. Night warming also reduced aphid survival under heat from 75% to 37%, and depressed adult performance by up to 50%. Overall, night warming exacerbated the detrimental effects of hot days on the intrinsic rate of population increase, which was predicted to drop by 30% when nighttime minimum temperatures exceeded 20 °C. Our novel findings on development challenge the ‘Kaufmann effect’, suggesting this is inapplicable to night warming likely to be encountered in nature. Although many average temperature models predict increasing pest outbreaks, our results suggest that outbreaks of some species might decrease due to the effects of night warming on population dynamics. This article is protected by copyright. All rights reserved.
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