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1.
When individuals disperse, they modify the physical and social composition of their reproductive environment, potentially impacting their fitness. The choice an individual makes between dispersal and philopatry is thus critical, hence a better understanding of the mechanisms involved in the decision to leave the natal area is crucial. We explored how combinations of behavioural (exploration, mobility, activity and stress response) and morphological (body mass) traits measured prior to dispersal were linked to the subsequent dispersal decision in 77 roe deer Capreolus capreolus fawns. Using an unusually detailed multi-trait approach, we identified two independent behavioural continuums related to dispersal. First, a continuum of energetic expenditure contrasted individuals of low mobility, low variability in head activity and low body temperature with those that displayed opposite traits. Second, a continuum of neophobia contrasted individuals that explored more prior to dispersal and were more tolerant of capture with those that displayed opposite traits. While accounting for possible confounding effects of condition-dependence (body mass), we showed that future dispersers were less neophobic and had higher energetic budgets than future philopatric individuals, providing strong support for a dispersal syndrome in this species.  相似文献   

2.
In cooperatively breeding species, restricted dispersal of offspring leads to clustering of closely related individuals, increasing the potential both for indirect genetic benefits and inbreeding costs. In apostlebirds (Struthidea cinerea), philopatry by both sexes results in the formation of large (up to 17 birds), predominantly sedentary breeding groups that remain stable throughout the year. We examined patterns of relatedness and fine-scale genetic structure within a population of apostlebirds using six polymorphic microsatellite loci. We found evidence of fine-scale genetic structure within the study population that is consistent with behavioural observations of short-distance dispersal, natal philopatry by both sexes and restricted movement of breeding groups between seasons. Global F(ST) values among breeding groups were significantly positive, and the average level of pairwise relatedness was significantly higher for individuals within groups than between groups. For individuals from different breeding groups, geographical distance was negatively correlated with pairwise relatedness and positively correlated with pairwise F(ST). However, when each sex was examined separately, this pattern was significant only among males, suggesting that females may disperse over longer distances. We discuss the potential for kin selection to influence the evolution and maintenance of cooperative breeding in apostlebirds. Our results demonstrate that spatial genetic structural analysis offers a useful alternative to field observations in examining dispersal patterns of cooperative breeders.  相似文献   

3.
Dispersal is a key demographic process, ultimately responsible for genetic connectivity among populations. Despite its importance, quantifying dispersal within and between populations has proven difficult for many taxa. Even in passerines, which are among the most intensely studied, individual movement and its relation to gene flow remains poorly understood. In this study we used two parallel genetic approaches to quantify natal dispersal distances in a Neotropical migratory passerine, the black-capped vireo. First, we employed a strategy of sampling evenly across the landscape coupled with parentage assignment to map the genealogical relationships of individuals across the landscape, and estimate dispersal distances; next, we calculated Wright’s neighborhood size to estimate gene dispersal distances. We found that a high percentage of captured individuals were assigned at short distances within the natal population, and males were assigned to the natal population more often than females, confirming sex-biased dispersal. Parentage-based dispersal estimates averaged 2400m, whereas gene dispersal estimates indicated dispersal distances ranging from 1600–4200 m. Our study was successful in quantifying natal dispersal distances, linking individual movement to gene dispersal distances, while also providing a detailed look into the dispersal biology of Neotropical passerines. The high-resolution information was obtained with much reduced effort (sampling only 20% of breeding population) compared to mark-resight approaches, demonstrating the potential applicability of parentage-based approaches for quantifying dispersal in other vagile passerine species.  相似文献   

4.
Male-biased dispersal is a common trait in mammals, including carnivores, but its genetic consequences at the population level have been rarely considered for solitary species. We used long-term genetic data from cougars (Puma concolor) in and around Yellowstone National Park to test predictions based on differences in dispersal behaviour among males and females. Consistent with frequent long-distance dispersal of males, we found support for our prediction of less than expected allele sharing in pair-wise comparisons. In contrast, female residents present at the same time and females separated by few generations failed to share more alleles than expected, contrary to our predictions based on limited female dispersal. However, we find that genetic contributions of females with higher reproductive success were still noticeable in subsequent generations, consistent with female offspring showing fidelity to their natal area. These results highlight the importance of male dispersal for inbreeding avoidance, but do not indicate that short-distance dispersal or philopatry in female cougars results in spatial clustering of related individuals.  相似文献   

5.
Dispersal is one of the most fundamental components of ecology, and affects processes as diverse as population growth, metapopulation dynamics, gene flow and adaptation. Although the act of moving from one habitat to another entails major costs to the disperser, empirical and theoretical studies suggest that these costs can be reduced by having morphological, physiological or behavioural specializations for dispersal. A few recent studies on different systems showed that individuals exhibit personality-dependent dispersal, meaning that dispersal tendency is associated with boldness, sociability or aggressiveness. Indeed, in several species, dispersers not only develop behavioural differences at the onset of dispersal, but display these behavioural characteristics through their life cycle. While personality-dependent dispersal has been demonstrated in only a few species, we believe that it is a widespread phenomenon with important ecological consequences. Here, we review the evidence for behavioural differences between dispersers and residents, to what extent they constitute personalities. We also examine how a link between personality traits and dispersal behaviours can be produced and how personality-dependent dispersal affects the dynamics of metapopulations and biological invasions. Finally, we suggest future research directions for population biologists, behavioural ecologists and conservation biologists such as how the direction and the strength of the relationship between personality traits and dispersal vary with ecological contexts.  相似文献   

6.
Why non-breeding subordinates of many animal societies tolerate group-living remains a pertinent question in evolutionary biology. The ecological constraints and benefits of philopatry hypotheses have the potential to explain the maintenance of group-living by specifying the ecological conditions favouring delayed dispersal over independent breeding by subordinates. In this study, I used field and laboratory experiments to investigate the role of ecological and social factors on the dispersal decisions of non-breeding subordinates in the coral-dwelling fish, Paragobiodon xanthosomus (Gobiidae). Subordinate dispersal was strongly influenced by ecological constraints (habitat saturation and risks of movement) and benefits of philopatry (relative coral size). Social factors, namely social rank and forcible eviction, did not affect the occurrence of subordinate dispersal. These results suggest that selection has favoured subordinate P. xanthosomus, which employ a mixed strategy—switching tactics in response to three ecological factors—despite having low mobility and extreme habitat-specific requirements. Furthermore, this study demonstrates the generality of the ecological constraints and benefits of philopatry hypotheses as explanations for group-living in species where subordinates are unrelated to breeders, provide no help and do not strictly delay dispersal.  相似文献   

7.
There is accumulating evidence that individuals leave their natal area and select a breeding habitat non-randomly by relying upon information about their natal and future breeding environments. This variation in dispersal is not only based on external information (condition dependence) but also depends upon the internal state of individuals (phenotype dependence). As a consequence, not all dispersers are of the same quality or search for the same habitats. In addition, the individual's state is characterized by morphological, physiological or behavioural attributes that might themselves serve as a cue altering the habitat choice of conspecifics. These combined effects of internal and external information have the potential to generate complex movement patterns and could influence population dynamics and colonization processes. Here, we highlight three particular processes that link condition-dependent dispersal, phenotype-dependent dispersal and habitat choice strategies: (1) the relationship between the cause of departure and the dispersers' phenotype; (2) the relationship between the cause of departure and the settlement behaviour and (3) the concept of informed dispersal, where individuals gather and transfer information before and during their movements through the landscape. We review the empirical evidence for these processes with a special emphasis on vertebrate and arthropod model systems, and present case studies that have quantified the impacts of these processes on spatially structured population dynamics. We also discuss recent literature providing strong evidence that individual variation in dispersal has an important impact on both reinforcement and colonization success and therefore must be taken into account when predicting ecological responses to global warming and habitat fragmentation.  相似文献   

8.
The lifetime movements of an individual determine the gene flow and invasion potential of the species. However, sex dependence of dispersal and selective pressures driving dispersal have gained much more attention than dispersal at different life and age stages. Natal dispersal is more common than dispersal between breeding attempts, but breeding dispersal may be promoted by resource availability and competition. Here, we utilize mark–recapture data on the nest‐box population of Siberian flying squirrels to analyze lifetime dispersal patterns. Natal dispersal means the distance between the natal nest and the nest used the following year, whereas breeding movements refer to the nest site changes between breeding attempts. The movement distances observed here were comparable to distances reported earlier from radio‐telemetry studies. Breeding movements did not contribute to lifetime dispersal distance and were not related to variation in food abundance or habitat patch size. Breeding movements of males were negatively, albeit not strongly, related to male population size. In females, breeding movement activity was low and was not related to previous breeding success or to competition between females for territories. Natal philopatry was linked to apparent death of a mother; that is, we did not find evidence for mothers bequeathing territories for offspring, like observed in some other rodent species. Our results give an example of a species in which breeding movements are not driven by environmental variability or nest site quality. Different evolutionary forces often operate in natal and breeding movements, and our study supports the view that juveniles are responsible for redistributing individuals within and between populations. This emphasizes the importance of knowledge on natal dispersal, if we want to understand consequences of movement ecology of the species at the population level.  相似文献   

9.

Background

Tiger populations are dwindling rapidly making it increasingly difficult to study their dispersal and mating behaviour in the wild, more so tiger being a secretive and solitary carnivore.

Methods

We used non-invasively obtained genetic data to establish the presence of 28 tigers, 22 females and 6 males, within the core area of Pench tiger reserve, Madhya Pradesh. This data was evaluated along with spatial autocorrelation and relatedness analyses to understand patterns of dispersal and philopatry in tigers within this well-managed and healthy tiger habitat in India.

Results

We established male-biased dispersal and female philopatry in tigers and reiterated this finding with multiple analyses. Females show positive correlation up to 7 kms (which corresponds to an area of approximately 160 km2) however this correlation is significantly positive only upto 4 kms, or 50 km2 (r  = 0.129, p<0.0125). Males do not exhibit any significant correlation in any of the distance classes within the forest (upto 300 km2). We also show evidence of female dispersal upto 26 kms in this landscape.

Conclusions

Animal movements are important for fitness, reproductive success, genetic diversity and gene exchange among populations. In light of the current endangered status of tigers in the world, this study will help us understand tiger behavior and movement. Our findings also have important implications for better management of habitats and interconnecting corridors to save this charismatic species.  相似文献   

10.
Sound management of species requires reliable estimates of dispersal. Indeed, dispersal of individuals among local populations is a key factor in the biology and persistence of local populations and metapopulations. Here, the small-scale dispersal pattern of a vulnerable species, the endemic Sardinian chalk hill blue butterfly, was studied by applying capture–recapture multistate models and a model selection based on AIC values. Model parameters were survival, capture and movement probabilities. The model selection showed that (a) survival probability of individuals varied between sexes, (b) capture probability varied between sexes and among patches, and (c) movement probability varied with direction. The probability of movement among adjacent local populations was generally low and ranged from 0.009 to 0.212. Movement probabilities were subsequently modeled using data on interpatch distance and donor patch population size or area. The ultrastructural biology-based models turned out to be the most appropriate models for inference, showing that dispersal decreases with increasing interpatch distance and increasing donor patch population size or area, and suggesting that butterfly dispersal is affected by patch geometry and the presence of conspecifics. The application of multistate models, the model selection approach, and ultrastructural modeling allowed testing the validity of some general hypotheses related to dispersal in metapopulations and helped elucidate the butterfly small-scale dispersal pattern.  相似文献   

11.
1. Obtaining empirical evidence of the consequences of dispersal distance on fitness is challenging in wild animals because long-term, unbiased data on reproduction, survival and movement are notoriously difficult to obtain. 2. Lifetime fitness correlates of natal dispersal distance were studied in an isolated population of the facultatively colonial lesser kestrel Falco naumanni (Fleischer) monitored during 8 years at north-eastern Spain, where most birds (83%) dispersed from their natal colony to settle at distances ranging from 112 m to 136.5 km. 3. Neither annual breeding success nor age at recruitment was affected by natal dispersal distance. However, a capture-mark-recapture analysis revealed that survival during the year following recruitment decreased exponentially with dispersal distance, with differences of up to 15% between philopatrics and long-distance dispersers. In subsequent years, it remained similar irrespective of the natal dispersal distance moved. These results did not seem to be biased by long-distance dispersers settling differentially in the periphery of the population (which could emigrate permanently and be considered dead in future occasions) or within-individual consistency in successive dispersal distances, so our results appear to reflect genuine survival differences between dispersal tactics. 4. Average lifetime fledgling production, average lifetime recruitment success and rate-sensitive individual fitness (λ(ind)) also decreased with the distance from the natal to the first-breeding colony, indicating that dispersal decisions early in life affecting immediate survival prospects may translate into long-term fitness costs. 5. Both survival and lifetime fitness models including continuous dispersal distances significantly improved the characterization of the effect on fitness compared with models considering dispersal as a discrete process (i.e. dispersal vs. philopatry at a colony level). 6. Long-distance dispersers were more likely to establish new colonies regardless of whether they recruited in the centre or the periphery of the population, revealing their important role in the colonization of unoccupied patches. Individuals experienced a higher probability of mortality in small and newly funded colonies, so lifetime fitness costs of dispersal seem to be explained by recruitment in sites where average quality is low because of high uncertainty in survival prospects.  相似文献   

12.
Dispersal is a key process in ecology, evolutionary and conservation biology. Studies like mark-release-recapture work, show patterns of movement, but do not provide insight into the behavioural mechanisms. We review and comment recent results on animal dispersal behaviour. Dispersal through a landscape can be realised in two different ways: as a by-product of routine movements associated with resource exploitation (like foraging or mate-searching) with high levels of returning, or, as special, fast and directed movements designed for displacement. We illustrate and discuss both classes of movements as behaviourally different types. These types of movement imply different assumptions and consequences. We point at potential biases of current studies (like mark-release-recapture studies) towards routine, explorative movements. A more accurate knowledge of the dispersal behaviour is important to model dispersal with more biological realism, but also to better understand evolutionary consequences (e.g. uncoupled evolution of routine and special movements) and conservation (e.g. relative importance of corridors). The contribution of routine movements to dispersal is expected to decline with habitat fragmentation. A species’ mobility is not a static trait, but a multiple trait, the components of which may evolve rapidly. The possibility of uncoupled selection on routine movements and real dispersal movements remains to be evaluated. Yet, we are only at the beginning of understanding the behavioural ecology of dispersal movements. A more careful treatment of behavioural components of mobility within observational and experimental studies of animal dispersal is needed.  相似文献   

13.
We develop a general theory of organism movement in heterogeneous populations that can explain the leptokurtic movement distributions commonly measured in nature. We describe population heterogeneity in a state-structured framework, employing advection-diffusion as the fundamental movement process of individuals occupying different movement states. Our general analysis shows that population heterogeneity in movement behavior can be defined as the existence of different movement states and among-individual variability in the time individuals spend in these states. A presentation of moment-based metrics of movement illustrates the role of these attributes in general dispersal processes. We also present a special case of the general theory: a model population composed of individuals occupying one of two movement states with linear transitions, or exchange, between the two states. This two-state "exchange model" can be viewed as a correlated random walk and provides a generalization of the telegraph equation. By exploiting the main result of our general analysis, we characterize the exchange model by deriving moment-based metrics of its movement process and identifying an analytical representation of the model's time-dependent solution. Our results provide general and specific theoretical explanations for empirical patterns in organism movement; the results also provide conceptual and analytical bases for extending diffusion-based dispersal theory in several directions, thereby facilitating mechanistic links between individual behavior and spatial population dynamics.  相似文献   

14.
The return of individual birds to a specific area in successional years, i.e. philopatry, is a remarkable behavioural trait. Here we report on the remarkably reversed: the complete absence of returning individuals of a migratory passerine with otherwise pronounced philopatry. At a high latitude study site in Abisko (68°32?N, 18°80?E) in northern Sweden none of the banded adult willow warblers Phylloscopus trochilus returned to breed 2011–2014. This is in stark contrast to all other reports in the literature and also to our two southern study sites (at 56°56?N, 18°10?E and at 58°94?N, 17°14?E) where 18–38% of adults returned. We investigated this aberrant pattern found in Abisko by analysing three parameters known to influence philopatry; nest predation, breeding success and breeding density, and predicted that absence of philopatry should co‐occur with low breeding success, low breeding density and/or high nest predation. The results did not corroborate this, except that breeding density was lower at Abisko (49–71 pairs km–2) than at the southern sites (106 pairs km–2, 101 pairs km–2). Instead, we suggest the hypothesis that the absence of philopatry is caused by an influx of southern, dispersal‐prone individuals deploying another breeding strategy and that this intra‐specific range expansion is enabled by milder climate and low population density.  相似文献   

15.
Ostensibly, it makes sense in a changeable world to condition behaviour and development on information when it is available. Nevertheless, unconditional behavioural and life history strategies are widespread. Here, we show how intergenerational effects can limit the evolutionary value of responding to reliable environmental cues, and thus favour the evolutionary persistence of otherwise paradoxical unconditional strategies. While cue-ignoring genotypes do poorly in the wrong environments, in the right environment they will leave many copies of themselves, which will themselves leave many copies, and so on, leading genotypes to accumulate in habitats in which they do well. We call this 'The Multiplier Effect'. We explore the consequences of the multiplier effect by focussing on the ecologically important phenomenon of natal philopatry. We model the environment as a large number of temporally varying breeding sites connected by natal dispersal between sites. Our aim is to identify which aspects of an environment promote the multiplier effect. We show, if sites remain connected through some background level of 'accidental' dispersal, unconditional natal philopatry can evolve even when there is density dependence (with its accompanying kin competition effects), and cues that are only mildly erroneous. Thus, the multiplier effect may underpin the evolution and maintenance of unconditional strategies such as natal philopatry in many biological systems.  相似文献   

16.
Spatial models commonly assume that dispersal rates are constant across individuals and environments and that movement directions are unbiased. These random-movement assumptions are inadequate to capture the range of dispersal behaviors revealed in diverse case studies. We examine an alternative assumption of directed movement, in which dispersal is a conditional and directional response by individuals to varying environmental conditions. Specifically, we assume individuals bias their movements to climb spatial fitness gradients. We compare the consequences of random and directed movement for local adaptation, the evolution of dispersal, and the reinforcement process. The implications of each movement strategy depend on the nature of environmental disturbance, and we examine the outcomes for undisturbed environments and with uncorrelated and autocorrelated disturbances. Both movement strategies offer advantages over sedentary life histories by allowing colonization of suitable habitats. However, random movement eventually becomes costly in stable environments because it inhibits local adaptation. In contrast, directed movement accelerates local adaptation. In disturbed environments, random movement offers bet-spreading advantages by distributing offspring across habitats. Despite being a more targeted strategy, an intermediate amount of directed movement provides similar bet-spreading benefits. These fitness consequences have implications for the evolution of dispersal. Dispersiveness is lost by random movers in undisturbed environments, is maintained in polymorphism with infrequent disturbances, and evolves when disturbances are uncorrelated. Directed movement becomes selectively neutral in the absence of disturbance, evolves when disturbances are autocorrelated, and is maintained in polymorphism with uncorrelated disturbances. Disturbance also determines the outcome of the reinforcement process for each strategy. For example, directed movers show no progress toward reinforcement in undisturbed environments, evolve random mating with uncorrelated disturbances, and can evolve assortative mating in infrequently disturbed environments.  相似文献   

17.
Natal dispersal has profound consequences for populations through the movement of individuals and genes. Habitat fragmentation reduces structural connectivity by decreasing patch size and increasing isolation, but understanding of how this impacts dispersal and the functional connectivity of landscapes is limited because many studies are constrained by the size of the study areas or sample sizes to accurately capture natal dispersal. We quantified natal dispersal probability and natal dispersal distances in a small migratory shorebird, the Southern Dunlin Calidris alpina schinzii, with data from two extensively monitored endangered metapopulations breeding in Sweden and Finland. In both metapopulations philopatry was strong, with individuals returning to or close to their natal patches more often than expected by chance, consistent with the patchy distribution of their breeding habitat. Dispersal probabilities were lower and dispersal distances were shorter in Sweden. These results provide a plausible explanation for the observed inbreeding and population decline of the Swedish population. The differences between Sweden and Finland were explained by patch‐specific differences. Between‐patch dispersal decreased with increasing natal patch size and distance to other patches. Our results suggest that reduced connectivity reduces movements of the philopatric Dunlin, making it vulnerable to the effects of inbreeding. Increasing connectivity between patches should thus be one of the main goals when planning future management. This may be facilitated by creating a network of suitably sized patches (20–100 ha), no more than 20 km apart from each other, from existing active patches that may work as stepping stones for movement, and by increasing nest success and pre‐fledging survival in small patches.  相似文献   

18.
The relative roles of ecological constraints, the benefits of philopatry, and the role of life history continue to be debated in the evolution of natal philopatry and cooperative breeding. We compare three routes to breeding: departing to search for territories as a floater, staying and queuing to inherit the natal territory, or queuing and eventually shifting to a neighboring vacancy. Our model assumed a dominance-structured population. It quantifies the benefits of philopatry for varying-rank subordinates and contrasts it against the benefit of dispersal. We apply the model to data on Siberian jay Perisoreus infaustus, a species in which retained offspring do not help at the nest. The results indicate that territorial inheritance plays a small role in this species (presumably due to inbreeding avoidance), and territory acquisition is less constrained for dispersing than philopatric offspring. Nevertheless, small family groups-one or, at the most, two same-sex queuers-are predicted to form because philopatric offspring gain nepotistic benefits that improve their survival. This fits with data on group sizes and supports the idea of the natal territory as a safe haven for waiting for breeding opportunities. We also discuss our predictions in the light of ecological constraints and clarify recent confusingly different predictions on the role of habitat saturation as an explanation for delayed dispersal and cooperative breeding. We argue that "ecological constraint" is too wide a term to yield useful predictive power and that it is more appropriate to examine the consequences of specific life-history traits on the success of dispersers.  相似文献   

19.
Dispersal, which is a crucial process in animal population and evolutionary ecology, is considered personality dependent. The fitness consequences of dispersal are important. However, they are difficult and rarely measured in wild populations. In this study, we investigated the behaviour and reproductive fitness in a plateau pika (Ochotona curzoniae) population for two continuous years through mark–recapture experiment, behavioural tests and microsatellite analysis of parentage. Our results determined that around 53.8% males and 16.7% females dispersed to 40.3 and 28.2 m away from their natal family, respectively. The aggression (attack frequency and duration) of philopatric individuals was significantly higher than that of dispersed ones, although significant differences in boldness did not exist between them. For both males and females, the offspring number of philopatric pikas was significantly higher than that of dispersed ones. This result indicated that inbreeding may occur in plateau pikas. Our findings highlighted the importance of integrating behavioural, ecological and genetic analyses to explore the mechanism of dispersal. The findings also suggested that personality may play an important role in life history.  相似文献   

20.
Sex differences in philopatry and dispersal have important consequences on the genetic structure of populations, social groups, and social relationships within groups. Among mammals, male dispersal and female philopatry are most common and closely related taxa typically exhibit similar dispersal patterns. However, among four well‐studied species of baboons, only hamadryas baboons exhibit female dispersal, thus differing from their congenerics, which show female philopatry and close‐knit female social relationships. Until recently, knowledge of the Guinea baboon social system and dispersal pattern remained sparse. Previous observations suggested that the high degree of tolerance observed among male Guinea baboons could be due to kinship. This led us to hypothesize that this species exhibits male philopatry and female dispersal, conforming to the hamadryas pattern. We genotyped 165 individuals from five localities in the Niokolo‐Koba National Park, Senegal, at 14 autosomal microsatellite loci and sequenced a fragment of the mitochondrial hypervariable region I (HVRI) of 55 individuals. We found evidence for higher population structuring in males than in females, as expected if males are the more philopatric sex. A comparison of relatedness between male–male and female–female dyads within and among communities did not yield conclusive results. HVRI diversity within communities was high and did not differ between the sexes, also suggesting female gene flow. Our study is the first comprehensive analysis of the genetic population structure in Guinea baboons and provides evidence for female‐biased dispersal in this species. In conjunction with their multilevel social organization, this finding parallels the observations for human hunter‐gatherers and strengthens baboons as an intriguing model to elucidate the processes that shaped the highly cooperative societies of Homo. Am. J. Primatol. 77:878–889, 2015. © 2015 The Authors. American Journal of Primatology Published by Wiley Periodicals Inc.  相似文献   

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