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In variable environments, habitats that are rich in resources often carry a higher risk of predation. As a result, natural selection should favour individuals that balance allocation of time to foraging versus avoiding predation through an optimal decision-making process that maximizes fitness. The behavioural trade-off between resource acquisition and risk avoidance is expected to be particularly acute during gestation and lactation, when the energetic demands of reproduction peak. Here, we investigated how reproductive female roe deer adjust their foraging activity and habitat use during the birth period to manage this trade-off compared with non-reproductive juveniles, and how parturition date constrains individual tactics of risk-resource management. Activity of reproductive females more than doubled immediately following parturition, when energy demand is highest. Furthermore, compared with non-reproductive juveniles, they increased their exposure to risk by using open habitat more during daytime and ranging closer to roads. However, these post-partum modifications in behaviour were particularly pronounced in late-parturient females who adopted a more risk-prone tactic, presumably to compensate for the growth handicap of their late-born offspring. In income breeders, individuals that give birth late may be constrained to trade risk avoidance for foraging during peak allocation to reproduction, with probable consequences for individual fitness. [ABSTRACT FROM AUTHOR]

In variable environments, habitats that are rich in resources often carry a higher risk of predation. As a result, natural selection should favour individuals that balance allocation of time to foraging versus avoiding predation through an optimal decision-making process that maximizes fitness. The behavioural trade-off between resource acquisition and risk avoidance is expected to be particularly acute during gestation and lactation, when the energetic demands of reproduction peak. Here, we investigated how reproductive female roe deer adjust their foraging activity and habitat use during the birth period to manage this trade-off compared with non-reproductive juveniles, and how parturition date constrains individual tactics of risk-resource management. Activity of reproductive females more than doubled immediately following parturition, when energy demand is highest. Furthermore, compared with non-reproductive juveniles, they increased their exposure to risk by using open habitat more during daytime and ranging closer to roads. However, these post-partum modifications in behaviour were particularly pronounced in late-parturient females who adopted a more risk-prone tactic, presumably to compensate for the growth handicap of their late-born offspring. In income breeders, individuals that give birth late may be constrained to trade risk avoidance for foraging during peak allocation to reproduction, with probable consequences for individual fitness. [ABSTRACT FROM AUTHOR]

[Display omitted] • We studied the parasite community and population structures from sheep and roe deer. • Generalist parasite species dominated the nemabiomes of sheep but also roe deer. • The presence of livestock may have modified drastically the nemabiome of roe deer. • There was high circulation of nematodes among sheep and roe deer populations at a regional scale. The growth of livestock farming and the recent expansion of wild ungulate populations in Europe favor opportunities for direct and/or indirect cross-transmission of pathogens. Comparatively few studies have investigated the epidemiology of gastro-intestinal nematode parasites, an ubiquitous and important community of parasites of ungulates, at the wildlife/livestock interface. In this study, we aimed to assess the influence of livestock proximity on the gastrointestinal nematode community of roe deer in a rural landscape located in southern France. Using ITS-2 rDNA nemabiome metabarcoding on fecal larvae, we analysed the gastrointestinal nematode communities of roe deer and sheep. In addition, we investigated Haemonchus contortus nad4 mtDNA diversity to specifically test parasite circulation among domestic and wild host populations. The dominant gastrointestinal nematode species found in both the roe deer and sheep were generalist species commonly found in small ruminant livestock (e.g. H. contortus), whereas the more specialised wild cervid nematode species (e.g. Ostertagia leptospicularis) were only present at low frequencies. This is in marked contrast with previous studies that found the nemabiomes of wild cervid populations to be dominated by cervid specialist nematode species. In addition, the lack of genetic structure of the nad4 mtDNA of H. contortus populations between host species suggests circulation of gastrointestinal nematodes between roe deer and sheep. The risk of contact with livestock only has a small influence on the nemabiome of roe deer, suggesting the parasite population of roe deer has been displaced by generalist livestock parasites due to many decades of sheep farming, not only for deer grazing close to pastures, but also at a larger regional scale. We also observed some seasonal variation in the nemabiome composition of roe deer. Overall, our results demonstrate significant exchange of gastrointestinal nematodes between domestic and wild ungulates, with generalist species spilling over from domestic ungulates dominating wild cervid parasite communities. [ABSTRACT FROM AUTHOR]

Accurate heritability estimates for fitness‐related traits are required to predict an organism's ability to respond to global change. Heritability estimates are theoretically expected to be inflated if, due to limited dispersal, individuals that share genes are also likely to share similar environments. However, if relatives occupy similar environments due, at least partly, to genetic variation for habitat selection, then accounting for environmental similarity in quantitative genetic models may result in diminished heritability estimates in wild populations. This potential issue has been pointed out in the literature, but has not been evaluated by empirical studies.Here, we investigate whether environmental similarity among individuals can be partly explained by genetic variation for habitat selection, and how this link potentially blurs estimates for heritability in fitness‐related traits.Using intensive GPS monitoring, we quantified home‐range habitat composition for 293 roe deer inhabiting a heterogeneous landscape to assess environmental similarity. To investigate if environmental similarity might harbour genetic variation, we combined genome‐wide data in a quantitative genetic framework to evaluate genetic variation for home‐range habitat composition, which is partly the result of habitat selection at settlement. Finally, we explored how environmental similarity affects heritability estimates for behaviours related to the risk avoidance–resource acquisition trade‐off (i.e. being in open habitat and distance to roads) and proxies of individual performance (i.e. body mass and hind foot length). We found substantial heritability for home‐range habitat composition, with estimates ranging from 0.40 (proportion of meadows) to 0.85 (proportion of refuge habitat). Accounting for similarity in habitat composition between relatives decreased the heritability estimates for both behavioural and morphological traits (reduction ranging from 55% to 100% and from 22% to 41% respectively). As a consequence, only half of these heritability estimates remained significantly different from zero.Our results show that similar genotypes occupy similar environments, which could lead to heritable variation being incorrectly attributed to environmental effects. To accurately distinguish the sources of phenotypic variation and predict the ability of organisms to respond to global change, it is necessary to develop quantitative genetic studies investigating the mechanisms underpinning environmental similarity among relatives. [ABSTRACT FROM AUTHOR]

Assessing the evolutionary potential of animal populations in the wild is crucial to understanding how they may respond to selection mediated by rapid environmental change (e.g. habitat loss and fragmentation). A growing number of studies have investigated the adaptive role of behaviour, but assessments of its genetic basis in a natural setting remain scarce. We combined intensive biologging technology with genome‐wide data and a pedigree‐free quantitative genetic approach to quantify repeatability, heritability and evolvability for a suite of behaviours related to the risk avoidance‐resource acquisition trade‐off in a wild roe deer (Capreolus capreolus) population inhabiting a heterogeneous, human‐dominated landscape. These traits, linked to the stress response, movement and space‐use behaviour, were all moderately to highly repeatable. Furthermore, the repeatable among‐individual component of variation in these traits was partly due to additive genetic variance, with heritability estimates ranging from 0.21 ± 0.08 to 0.70 ± 0.11 and evolvability ranging from 1.1% to 4.3%. Changes in the trait mean can therefore occur under hypothetical directional selection over just a few generations. To the best of our knowledge, this is the first empirical demonstration of additive genetic variation in space‐use behaviour in a free‐ranging population based on genomic relatedness data. We conclude that wild animal populations may have the potential to adjust their spatial behaviour to human‐driven environmental modifications through microevolutionary change. [ABSTRACT FROM AUTHOR]

Although inter‐individual heterogeneity in many aspects of dispersal behaviour is widely reported, this key life‐history trait is predominantly modelled as a dichotomous state of philopatry versus dispersal. The increasing body of evidence for dispersal syndromes (i.e. a suite of correlated morphological, behavioural and life‐history traits associated with dispersal) implies substantial but, to date, undocumented individual heterogeneity in behavioural tactics during dispersal. Using a large sample (n = 154) of GPS monitored juvenile roe deer Capreolus capreolus, we evaluated among‐individual behavioural heterogeneity in dispersal tactics, and the individual and environmental drivers of these alternative tactics. We developed a sequential three‐stage decision tree based on space use stability, exploration events and the directionality of movement. We identified six discrete alternative behavioural tactics during the dispersal period which were characterised by different timing, amplitude and duration in movement: slightly less than half of the deer were sedentary, either 'strictly philopatric' or 'explorers', which subsequently settled on their natal range; around 40% dispersed ('classic dispersal'), of which, one in six subsequently aborted, moving back to their natal range ('aborted dispersal'); finally, around 15% expressed either a 'progressive dispersal' tactic, gradually moving away from their natal area to settle elsewhere, or a 'multi‐range' tactic. The propensity to express an alternative dispersal tactic was strongly influenced by an individual's local environment. In particular, when landscape heterogeneity, resource quality and human‐related disturbance in the natal range were low, individuals were 1) more likely to adopt the alternative tactics of either progressive dispersal or multi‐ranging, but 2) also more likely to abort their dispersal attempt. Our work indicates that natal dispersal is likely not a single uniform behaviour, but that individuals may adopt a variety of alternative movement tactics which are likely governed by different selection pressures, with potentially important impacts for population dynamics and functioning. [ABSTRACT FROM AUTHOR]

Dispersal is a key mechanism enabling species to adjust their geographic range to rapid global change. However, dispersal is costly and environmental modifications are likely to modify the cost–benefit balance of individual dispersal decisions, for example, by decreasing functional connectivity.Dispersal costs occur during departure, transience and settlement, and are levied in terms of energy, risk, time and lost opportunity, potentially influencing individual fitness. However, to the best of our knowledge, no study has yet quantified the energetic costs of dispersal across the dispersal period by comparing dispersing and philopatric individuals in the wild.Here, we employed animal‐borne biologgers on a relatively large sample (N = 105) of juvenile roe deer to estimate energy expenditure indexed using the vector of dynamic body acceleration and mobility (distance travelled) in an intensively monitored population in the south‐west of France. We predicted that energy expenditure would be higher in dispersers compared to philopatric individuals. We expected costs to be (a) particularly high during transience, (b) especially high in the more fragmented areas of the landscape and (c) concentrated during the night to avoid disturbance caused by human activity.There were no differences in energy expenditure between dispersers and philopatric individuals during the pre‐dispersal phase. However, dispersers expended around 22% more energy and travelled around 63% further per day than philopatric individuals during transience. Differences in energy expenditure were much less pronounced during the settlement phase. The costs of transience were almost uniquely confined to the dawn period, when dispersers spent 23% more energy and travelled 112% further than philopatric individuals. Finally, the energetic costs of transience per unit time and the total distance travelled to locate a suitable settlement range were higher in areas of high road density.Our results provide strong support for the hypothesis that natal dispersal is energetically costly and indicate that transience is the most costly part of the process, particularly in fragmented landscapes. Further work is required to link dispersal costs with fitness components so as to understand the likely outcome of further environmental modifications on the evolution of dispersal behaviour. [ABSTRACT FROM AUTHOR]

The balance between resource acquisition and risk avoidance should vary according to personality type, with potential knock-on effects for fitness. Although previous studies have suggested a link between boldness and fitness components, little evidence is available on the behavioural mechanisms mediating this relationship in the wild. Because habitat use is the outcome of the trade-off between the costs and benefits associated with using each habitat type, we evaluated between-individual differences in habitat use of 64 GPS-collared female roe deer, Capreolus capreolus , using multinomial logit mixed models. To investigate whether deer differed in their habitat use tactics in relation to their personality type and their annual reproductive success, we assessed the link between individual habitat use patterns, boldness (measured as the strength of behavioural responsiveness to handling) and annual reproductive success (measured by the presence/absence of fawns at heel during autumn). Although daily and seasonal variations in the risk–resource landscapes clearly drove patterns of habitat use, individuals adopted contrasting habitat use tactics depending on their position along the shy–bold gradient and their reproductive status. Shy individuals occupied safer woodland more frequently, even at night when risk is lower. In contrast, bold individuals were better able to exploit rich open habitats. When this included mature autumn crops, these females weaned more offspring. Finally, irrespective of personality type, females that used meadows more often also achieved higher annual reproductive success. Overall, we demonstrate that individuals express divergent habitat use tactics as a function of their ability to avoid exposure to risk and their annual reproductive success. Highlights • We measured habitat use, boldness and reproductive success in 64 female roe deer. • Spatiotemporal variations in the risk-resource trade-off shape deer habitat use. • The way individuals use their environment also depends on their personality type. • Differences in habitat use between personalities are linked to reproductive success. • Individual habitat use tactics mediate the personality – fitness link in the wild. [ABSTRACT FROM AUTHOR]

Anaplasma phagocytophilum is a bacterial pathogen mainly transmitted by Ixodes ricinus ticks in Europe. It infects wild mammals, livestock, and, occasionally, humans. Roe deer are considered to be the major reservoir, but the genotypes they carry differ from those that are found in livestock and humans. Here, we investigated whether roe deer were the main source of the A. phagocytophilum genotypes circulating in questing I. ricinus nymphs in a fragmented agricultural landscape in France. First, we assessed pathogen prevalence in 1837 I. ricinus nymphs (sampled along georeferenced transects) and 79 roe deer. Prevalence was dramatically different between ticks and roe deer: 1.9% versus 76%, respectively. Second, using high-throughput amplicon sequencing, we characterized the diversity of the A. phagocytophilum genotypes found in 22 infected ticks and 60 infected roe deer; the aim was to determine the frequency of co-infections. Only 22.7% of infected ticks carried genotypes associated with roe deer. This finding fits with others suggesting that cattle density is the major factor explaining infected tick density. To explore epidemiological scenarios capable of explaining these patterns, we constructed compartmental models that focused on how A. phagocytophilum exposure and infection dynamics affected pathogen prevalence in roe deer. At the exposure levels predicted by the results of this study and the literature, the high prevalence in roe deer was only seen in the model in which superinfections could occur during all infection phases and when the probability of infection post exposure was above 0.43. We then interpreted these results from the perspective of livestock and human health. [ABSTRACT FROM AUTHOR]

Because avoiding predation is crucial for fitness, foraging animals must trade acquisition of high-quality resources against risk avoidance when the best resources occur in locations with high predation risk. Although optimality models predict the distance at which an animal should initiate vigilance and flight, many studies have shown that animals generally flee soon after detecting an approaching threat, supporting the ‘flush early and avoid the risk’ (FEAR) hypothesis. Despite this, flight behaviour varies markedly depending on context, suggesting some behavioural plasticity in the response of prey to a given threat. We evaluated the degree of plasticity in the flight responses of roe deer, Capreolus capreolus , a highly flexible species which thrives in human-dominated landscapes. Based on individually identifiable animals and a standardized flight initiation protocol, we measured the distance at which a deer detected an approaching threat, and the distance at which it subsequently initiated flight. Our results provide strong support for the FEAR hypothesis, suggesting that alert and flight responses are strongly coupled in roe deer. However, the perceived level of both risk (in terms of landscape openness and proximity to human infrastructure) and reward (in terms of habitat quality) influenced the time it took for a deer to detect an approaching threat, and the subsequent time for which the threat was tolerated prior to flight. Overall, our findings indicate that although roe deer minimize monitoring costs when assessing risk by fleeing early, they also adjust their monitoring and flight responses to the local risk–resource trade-off. [ABSTRACT FROM AUTHOR]

Dispersal is a key life-history trait governing the response of individuals, populations and species to changing environmental conditions. In the context of global change, it is therefore essential to better understand the respective role of condition-, phenotype- and genetic-dependent drivers of dispersal behaviour. Although the importance of immune function and pathogen infestation in determining patterns of dispersal is increasingly recognised, no study to our knowledge has yet investigated the influence of immune gene variability on dispersal behaviour. Here, we filled this knowledge gap by assessing whether individual heterozygosity at five immune gene loci (one from the Major histocompatibility complex and four from encoding Toll-like receptors) influences roe deer natal dispersal. We found that dispersal propensity was affected by immune gene diversity, suggesting potential pathogen-mediated selection through over-dominance. However, the direction of this effect differed between high and low quality individuals, suggesting that dispersal propensity is driven by two different mechanisms. In support of the condition-dependent dispersal hypothesis, dispersal propensity increased with increasing body mass and, among high quality individuals only (standardized body mass > 18 kg), with increasing immune gene diversity. However, among poor quality individuals, we observed the opposite pattern such that dispersal propensity was higher for individuals with lower immune gene diversity. We suggest that these poor quality individuals expressed an emergency dispersal tactic in an attempt to escape a heavily infested environment associated with poor fitness prospects. Our results have potentially important consequences in terms of population genetics and demography, as well as host-pathogen evolution. [ABSTRACT FROM AUTHOR]

Non-consumptive effects of predators result from the cost of responses to perceived risk. Prey modulate risk exposure through flexible habitat selection at multiple scales which, in interaction with landscape constraints, determines their use of risky habitats. Identifying the relative contributions of landscape constraints and habitat selection to risk exposure is a critical first step towards a mechanistic understanding of non-consumptive effects. Here, we provide an integrative multi-scale study of roe deer spatial responses to variable hunting pressure along a landscape gradient of open habitats and dispersed refuges. Between low-risk and high-risk periods, we investigated shifts in 1) home-range location, 2) probability of using risky habitats (between-habitat scale) and 3) distance to the nearest refuge (within-habitat scale). For 2) and 3), we disentangled the contributions of landscape constraints and habitat selection to risky habitat use. We found that when risk was high, roe deer did not shift their home-range, but generally decreased their use of risky habitats, and sometimes reduced their distance to cover (particularly older animals). There was a functional response in between-habitat selection, with animals living in more open landscapes responding more than those living in landscapes with more refuges. However, individuals living in more open landscapes avoided open risky habitat less. Finally, we found that among-individual variation in risk exposure was generally, but not always, minimized by habitat selection across gradients of landscape constraints. To our knowledge, this is the first study simultaneously documenting prey responses to risk at the within-habitat, between-habitat and home-range scales. Our results support the view that between-habitat selection acts at a higher hierarchical level than within-habitat selection, and provide a framework for disentangling the contributions of habitat selection and landscape constraints to risk exposure. Selection cannot always compensate for landscape constraints, indicating a need for further investigation of the processes underlying habitat selection. [ABSTRACT FROM AUTHOR]

Individual differences in behavior may strongly shape life-history trajectories. However, few empirical studies to date have investigated the link between behavioral traits and fitness, especially in wild populations. We measured the impact of coping style in female roe deer (Capreolus capreolus) on early survival of their offspring. Specifically, we expected offspring of proactive mothers, which should be more mobile and aggressive, to survive better than those of reactive females, which should be more passive and react less in stressful contexts. To test this prediction, we accounted for confounding effects of variation in early survival linked to habitat heterogeneity, as we also expected bed-site selection to impact fawn survival. Fawn survival was highly dependent on the interaction between habitat use and the coping style of the mother. As expected, fawns of proactive mothers survived better in open habitats. However, unexpectedly, fawns of reactive mothers had the highest survival in closed habitats. Our findings provide clear evidence that interindividual differences in the coping style of the mother can markedly impact early offspring survival and, thereby, female fitness, in wild populations of mammals. Moreover, we provide evidence that fitness consequences of copying styles are habitat-dependent, providing a possible mechanism for the maintenance of within-population variation in behavior. [ABSTRACT FROM AUTHOR]

Although theoretical studies have predicted a link between individual multilocus heterozygosity and dispersal, few empirical studies have investigated the effect of individual heterozygosity on dispersal propensity or distance. We investigated this link using measures of heterozygosity at 12 putatively neutral microsatellite markers and natal dispersal behaviour in three contrasting populations of European roe deer ( Capreolus capreolus), a species displaying pre-saturation condition-dependent natal dispersal. We found no effect of individual heterozygosity on either dispersal propensity or dispersal distance. Average heterozygosity was similar across the three studied populations, but dispersal propensity and distance differed markedly among them. In Aurignac, dispersal propensity and distance were positively related to individual body mass, whereas there was no detectable effect of body mass on dispersal behaviour in Chizé and Trois Fontaines. We suggest that we should expect both dispersal propensity and distance to be greater when heterozygosity is lower only in those species where dispersal behaviour is driven by density-dependent competition for resources. [ABSTRACT FROM AUTHOR]

The way an individual reacts to the risk of predation or disturbance may have important consequences for its immediate and future survival. Risk is likely perceived differently by individuals in relation to among-individual differences in correlated behavioral traits, that is, syndromes or personalities. Given that animals can avoid the risk of predation/disturbance through modification of their habitat use, we might expect individuals of differing behavioral types to adopt contrasting tactics of habitat use when faced with risky or stressful situations. We studied the relationship between habitat use and among-individual variation in behavioral profile in a population of roe deer. We hypothesized that an individual's habitat use tactics should be related to their capacity to cope with risky situations. In particular, we predicted that more reactive (risk-averse) roe deer, with relatively high behavioral response and high body temperature at capture, long flight distances and which were more vigilant during feeding, should use riskier open habitat less, particularly when risk is high. We found that although the use of open habitat during the day was negatively correlated with the indices of reactivity at capture, it was also positively correlated with indices of reactivity while foraging in open habitat. Furthermore, most of the behavioral parameters we measured were intercorrelated and moderately repeatable, potentially indexing personality traits. We conclude that there is substantial interindividual variability in how individuals manage risky situations which imposes constraints on how they are able to exploit high-risk habitats, suggesting the existence of a risk management syndrome in this large herbivore. [ABSTRACT FROM AUTHOR]

Parasite abundance has been shown to have major consequences for host fitness components such as survival and reproduction. However, although natal dispersal is a key life history trait, whether an individual's decision to disperse or not is influenced by the abundance of parasites it carries remains mostly unknown. Current and opposing hypotheses suggest that infected individuals should either be philopatric to avoid the energetic costs of dispersal (condition dependence) or disperse to escape from heavily parasitised habitats. From intensive monitoring of a roe deer population inhabiting a multi-use and spatially heterogeneous agricultural landscape, we evaluated the link between an individual's parasite abundance and its propensity to disperse, while accounting for confounding effects of body mass. Dispersal propensity generally decreased with both increasing nematode abundance and with decreasing body mass. Within the dispersing segment of the population, individuals with high nematode abundance left their natal home range later in the season than less parasitised deer. These results clearly show that parasite abundance is an important component of condition-dependent dispersal in large herbivores. However, unexpectedly, three individuals that were both heavily parasitised and of low body mass dispersed. We suggest that this 'leave it' response to high parasite levels in the natal habitat could represent a last ditch attempt to improve reproductive prospects, constituting a form of emergency life history strategy. [ABSTRACT FROM AUTHOR]