Evidence of Eelgrass (Zostera marina) Seed Dispersal by Northern Diamondback Terrapin (Malaclemys terrapin terrapin) in Lower Chesapeake Bay

The initial discovery in May 2009 of eelgrass (Zostera marina) seeds in fecal samples of wild-caught northern diamondback terrapins (Malaclemys terrapin terrapin) was the first field evidence of eelgrass seed ingestion in this species. This finding suggested the potential of terrapins as seed dispersers in eelgrass beds, which we sampled for two additional years (2010 and 2011). Seeds were only found in feces of terrapins captured prior to June 8 in all three years, coinciding with eelgrass seed maturation and release. Numbers of seeds in terrapin feces varied annually and decreased greatly in 2011 after an eelgrass die off in late 2010. The condition of seeds in terrapin feces was viable-mature, germinated, damaged, or immature. Of terrapins captured during time of seed release, 97% were males and juvenile females, both of which had head widths <30 mm. The fraction of individuals with ingested seeds was 33% for males, 35% for small females, and only 6% for large (mature) females. Probability of seed ingestion decreased exponentially with increasing terrapin head width; only males and small females (head width <30 mm) were likely to be vectors of seed dispersal. The characteristic that diamondback terrapins have well-defined home ranges allowed us to estimate the number of terrapins potentially dispersing eelgrass seeds annually. In seagrass beds of the Goodwin Islands region (lower York River, Virginia), there were 559 to 799 terrapins, which could disperse between 1,341 and 1,677 eelgrass seeds annually. These would represent a small proportion of total seed production within a single seagrass bed. However, based on probable home range distances, terrapins can easily traverse eelgrass meadow boundaries, thereby dispersing seeds beyond the bed of origin. Given the relatively short dispersion distance of eelgrass seeds, the diamondback terrapin may be a major source of inter-bed seed dispersal and genetic diversity.     

Effects of roads and crabbing pressures on diamondback terrapin populations in coastal Georgia

Human activities, including the harvesting of natural resources and land development, place substantial pressure on wildlife. The diamondback terrapin (Malaclemys terrapin) is a small, estuarine species of emydid turtle in decline and at risk due to a suite of human activities. Vehicle-induced mortality from increasing coastal traffic and bycatch mortality in crab pots have been recognized as 2 of the primary conservation concerns for terrapins. We used mark-recapture estimates of terrapin density and sex ratio from repeated seining samples of 29 randomly stratified selected tidal creeks to evaluate the current relationships between road and crabbing pressures and the abundance, sex ratio, and size distribution of terrapin populations along the Georgia coast. We obtained 2005 captures of 1,547 individual terrapins among 29 tidal creeks sampled. Population density estimates ranged from 0 to 1,040 terrapins/km among tidal creeks with a median density of 65 terrapins/km. Among all sites, terrapin density declined with increasing crabbing activity within the creek, but was not related to proximity to roads. Sex ratios did not vary significantly with crabbing activity or proximity to roads; however, we found a significantly larger proportion of smaller-sized terrapins in creeks with no crabbing activity. Although roads may have significant localized effects on terrapin populations, we found no measurable association between proximity to roads and current variation in terrapin density along the Georgia coast. However, we did find that terrapin density and the proportion of smaller sized individuals within the population were negatively associated with crabbing activities. Bycatch from commercial and recreational activities threaten many species. We add to a growing body of research showing crabbing activities are affecting diamondback terrapin populations across much of the species' range. States committed to the conservation of terrapins and coastal species should focus on reducing bycatch risk; for example by regulating soak times and locations, requiring the use of bycatch reduction devices, and removing abandoned or lost crab pots from coastal habitats. © 2011 The Wildlife Society.     

Population genetics of the diamondback terrapin (Malaclemys terrapin)

We examined the population genetic structure of the diamondback terrapins (Malaclemys terrapin), within and among estuaries. Based on mark-recapture studies, these estuarine turtles have high site fidelity that is likely to make them vulnerable to local extinctions. We tested if observed site fidelity of adults would be reflected in intraestuarine population genetic structure of six highly polymorphic microsatellite loci (five tetranucleotide and one dinucleotide). No evidence was found for population structuring within the Charleston estuary nor among three different estuaries in South Carolina. We then examined four other terrapin populations from North Carolina to New York, as well as from the Florida Keys and from Texas. With increasing geographical distance, genetic differentiation increased from South Carolina through New York, but overall values were low. The dinucleotide locus contributed significantly more to the genetic differentiation of some population comparisons than any of the other loci. Interestingly, terrapins from South Carolina to New York were much more genetically similar to those from Texas (rho = 0.154) than to those from Florida (rho = 0.357). We attribute this pattern to extensive translocations of terrapins during the early 20th century to replenish diminished populations and to provide turtle farms with stocks. Terrapins collected in Texas were especially sought for shipment to the northeastern US because of their larger size. Our study indicates no population structure within or among adjacent estuaries. Thus, the mark-recapture information from adult and subadult feeding locations is a poor predictor of population genetic structure. Additionally, it appears that past human activities may have drastically altered the genetics of current populations. Finally, our data suggest that translocation of eggs or head starting of terrapins within estuaries or among adjacent estuaries is acceptable from a genetic standpoint.     

Lifetime philopatry in the blue-footed booby: a longitudinal study

Philopatry over the lifetime and its relationship with reproductivesuccess were examined using longitudinal records of nest locationand reproduction of individual blue-footed boobies. Males showedshorter natal dispersal than females, and natal dispersal distanceof both sexes were unrelated to either first reproductive successor lifetime reproductive success. Throughout the early lifetime,males and females nested closer to their first breeding sitesthan to their natal sites, and comparison with a simulationof successive breeding dispersals in random directions showedthat male and female blue-footed boobies are philopatric tothe first breeding site. Therefore, throughout the early lifetime,the first breeding site seems to function as a point of referencefor breeding site use together with the previous season's site.Males and females with shorter natal dispersal distances showedstronger lifetime philopatry to their first breeding sites,suggesting stable individual variation in competitive abilityor dispersal phenotype. However, early lifetime philopatry tofirst breeding sites was unrelated to annual breeding success.Compared with simple fidelity to previous breeding sites, lifetimephilopatry to first breeding sites should result in increasedkin interactions and greater selection for kin recognition,altruism and inbreeding avoidance, as well as long-term familiaritywith neighbors.     

Detecting female precise natal philopatry in green turtles using assignment methods

It is well established that sea turtles return to natal rookeries to mate and lay their eggs, and that individual females are faithful to particular nesting sites within the rookery. Less certain is whether females are precisely returning to their natal beach. Attempts to demonstrate such precise natal philopatry with genetic data have had mixed success. Here we focused on the green turtles of three nesting sites in the Ascension Island rookery, separated by 5-15 km. Our approach differed from previous work in two key areas. First, we used male microsatellite data (five loci) reconstructed from samples collected from their offspring (N = 17) in addition to data for samples taken directly from females (N = 139). Second, we employed assignment methods in addition to the more traditional F-statistics. No significant genetic structure could be demonstrated with F(ST). However, when average assignment probabilities of females were examined, those for nesting populations in which they were sampled were indeed significantly higher than their probabilities for other populations (Mann-Whitney U-test: P < 0.001). Further evidence was provided by a significant result for the mAI(C) test (P < 0.001), supporting greater natal philopatry for females compared with males. The results suggest that female natal site fidelity was not sufficient for significant genetic differentiation among the nesting populations within the rookery, but detectable with assignment tests.     

Role of breeding and natal movements in lifetime dispersal of a forest‐dwelling rodent

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.     

Genetic consequences of sex-biased dispersal in a solitary carnivore: Yellowstone cougars

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.     

Unsustainable anthropogenic mortality disrupts natal dispersal and promotes inbreeding in leopards

Anthropogenic mortality of wildlife is typically inferred from measures of the absolute decline in population numbers. However, increasing evidence suggests that indirect demographic effects including changes to the age, sex, and social structure of populations, as well as the behavior of survivors, can profoundly impact population health and viability. Specifically, anthropogenic mortality of wildlife (especially when unsustainable) and fragmentation of the spatial distribution of individuals (home‐ranges) could disrupt natal dispersal mechanisms, with long‐term consequences to genetic structure, by compromising outbreeding behavior and gene flow. We investigate this threat in African leopards (Panthera pardus pardus), a polygynous felid with male‐biased natal dispersal. Using a combination of spatial (home‐range) and genetic (21 polymorphic microsatellites) data from 142 adult leopards, we contrast the structure of two South African populations with markedly different histories of anthropogenically linked mortality. Home‐range overlap, parentage assignment, and spatio‐genetic autocorrelation together show that historical exploitation of leopards in a recovering protected area has disrupted and reduced subadult male dispersal, thereby facilitating opportunistic male natal philopatry, with sons establishing territories closer to their mothers and sisters. The resultant kin‐clustering in males of this historically exploited population is comparable to that of females in a well‐protected reserve and has ultimately led to localized inbreeding. Our findings demonstrate novel evidence directly linking unsustainable anthropogenic mortality to inbreeding through disrupted dispersal in a large, solitary felid and expose the genetic consequences underlying this behavioral change. We therefore emphasize the importance of managing and mitigating the effects of unsustainable exploitation on local populations and increasing habitat fragmentation between contiguous protected areas by promoting in situ recovery and providing corridors of suitable habitat that maintain genetic connectivity.     

Population genetic structure and direct observations reveal sex‐reversed patterns of dispersal in a cooperative bird

Sex‐biased dispersal is pervasive and has diverse evolutionary implications, but the fundamental drivers of dispersal sex biases remain unresolved. This is due in part to limited diversity within taxonomic groups in the direction of dispersal sex biases, which leaves hypothesis testing critically dependent upon identifying rare reversals of taxonomic norms. Here, we use a combination of observational and genetic data to demonstrate a rare reversal of the avian sex bias in dispersal in the cooperatively breeding white‐browed sparrow weaver (Plocepasser mahali). Direct observations revealed that (i) natal philopatry was rare, with both sexes typically dispersing locally to breed, and (ii), unusually for birds, males bred at significantly greater distances from their natal group than females. Population genetic analyses confirmed these patterns, as (i) corrected Assignment index (AIc), F_ST tests and isolation‐by‐distance metrics were all indicative of longer dispersal distances among males than females, and (ii) spatial autocorrelation analysis indicated stronger within‐group genetic structure among females than males. Examining the spatial scale of extra‐group mating highlighted that the resulting ‘sperm dispersal’ could have acted in concert with individual dispersal to generate these genetic patterns, but gamete dispersal alone cannot account entirely for the sex differences in genetic structure observed. That leading hypotheses for the evolution of dispersal sex biases cannot readily account for these sex‐reversed patterns of dispersal in white‐browed sparrow weavers highlights the continued need for attention to alternative explanations for this enigmatic phenomenon. We highlight the potential importance of sex differences in the distances over which dispersal opportunities can be detected.     

Reverse sex-biased philopatry in a cooperative bird: genetic consequences and a social cause

The genetic structure of a group or population of organisms can profoundly influence the potential for inbreeding and, through this, can affect both dispersal strategies and mating systems. We used estimates of genetic relatedness as well as likelihood-based methods to reconstruct social group composition and examine sex biases in dispersal in a Costa Rican population of white-throated magpie-jays ( Calocitta formosa , Swainson 1827), one of the few birds suggested to have female-biased natal philopatry. We found that females within groups were more closely related than males, which is consistent with observational data indicating that males disperse upon maturity, whereas females tend to remain in their natal territories and act as helpers. In addition, males were generally unrelated to one another within groups, suggesting that males do not disperse with or towards relatives. Finally, within social groups, female helpers were less related to male than female breeders, suggesting greater male turnover within groups. This last result indicates that within the natal group, female offspring have more opportunities than males to mate with nonrelatives, which might help to explain the unusual pattern of female-biased philopatry and male-biased dispersal in this system. We suggest that the novel approach adopted here is likely to be particularly useful for short-term studies or those conducted on rare or difficult-to-observe species, as it allows one to establish general patterns of philopatry and genetic structure without the need for long-term monitoring of identifiable individuals.     

Highly asymmetric fine-scale genetic structure between sexes of African striped mice and indication for condition dependent alternative male dispersal tactics

Sex-biased dispersal is observed in many taxa, but few studies have compared sex-biased dispersal among and within populations. We addressed the magnitude and habitat dependency of sex-biased dispersal in social African striped mice by separating group-related from population-related genetic variance to understand the contribution of each sex to deme structure. As dispersal over unoccupied habitat is likely to be more costly than dispersal within a population, we predicted that individuals leaving the natal population have a lower body condition, being inferior to heavier territorial individuals. Fine-scale genetic structure was detected in both sexes. Female relatedness decreased continuously from R = 0.21 at 25 m to zero at 500 m. Maximum male relatedness R = 0.05 was constant at distances between 25 and 75 m, becoming zero at 100 m. Genetic variance (F(ST) ) among seven locations was significantly higher in females than in males, while inbreeding estimates (F(IS) ) were significantly higher in males than in females. Assignment tests estimated significantly more migrants among males, while Bayesian clustering estimated only a single genetic unit cluster for males among the seven locations. The mean body mass of migrant males (44 g) was significantly lower than for males that remained resident and thus dispersed within their sub-population (48 g). Combined, the results showed habitat-independent male-biased dispersal and high female philopatry, and suggested that body condition was more important than kinship in male dispersal decisions. We suggest that locally inferior males are important for gene flow between sub-populations. Thus, males might follow alternative dispersal tactics.     

Population ecology of the white-nosed coati (Nasua narica) on Barro Colorado Island, Panama

The white-nosed coati, Nasua narica , is a common Neotropical carnivore with a social structure of band-living adult females and solitary adult males. A coati population on Barro Colorado Island, Panama, was studied over a four-year period by mark-recapture, radiotelemetry. and direct observation of habituated individuals. The population density was approximately 51.5 individuals/km² and the sex ratio was 1:1. Band size varied from six to 26 individuals (mean = 15.3) with extensive fluctuation within and between years. Mean foraging group size was smaller (7.2 individuals) than population group size, and fluctuated with food availability, synchronous parturition, and the emigration of mature males. Mean home-range size of six bands was 0.33 km², and ranges of adjacent bands overlapped from 0–66%. One band fissioned during the study; however, the resulting bands did not disperse from the original home range. Seven adult males had a mean home-range size of 0.37 km², each extensively overlapping the home ranges of several other males. Observations of 10 adult males whose natal bands were known indicate that when males disperse they do not simultaneously leave the band's home range. Rather, their home ranges remain within or broadly overlapping those of their natal bands. This dispersal pattern is unusual within the order Carnivora.     

Sex-bias and timing of natal dispersal in cooperatively breeding Puff-throated Bulbuls Alophoixus pallidus

While natal dispersal can have a significant impact on population dynamics, it is typically difficult to quantify. We investigated timing of natal dispersal of the cooperatively breeding Puff-throated Bulbul Alophoixus pallidus in a tropical evergreen forest by modelling the probability of staying in or dispersing from their natal territory whilst taking into account the effects of sex, group size, and the presence of helper(s). Birds did not disperse until the beginning of and during the breeding season following the hatching year. Dispersal was strongly female-biased both in frequency and distance: most females (95%) dispersed away from their natal territories, and of those relocated, traversed 2–7 territories. In contrast, 50% of males remained in the natal territory as helpers in their second year, while relocated dispersing males crossed 1–2 territories. Natal dispersal was not influenced by either group size or the presence of helpers. Males that fledged earlier in the breeding season exhibited higher rates of philopatry than the males that fledged later, but no correlation between fledging date and philopatry was observed in females. The probability of staying in the natal territory during the second year was 0.58 ± 0.14 SE and 0.05 ± 0.04 for males and females, respectively. These findings may add to our understanding of how natal dispersal can reflect social patterns and kin structure in cooperative breeding species from a little-studied tropical forest region.     

Genetic structure at three spatial scales is consistent with limited philopatry in Ricord's Rock Iguanas (Cyclura ricordii)

Cyclura ricordii is an endemic iguana from Hispaniola Island and is threatened on the IUCN Red List. The main threats are predation by introduced mammals, habitat destruction, and hunting pressure. The present study focused on two nesting sites from Pedernales Province in the Dominican Republic. The hypothesis that natal philopatry influences dispersal and nest‐site selection was tested. Monitoring and sampling took place in 2012 and 2013. Polymorphic markers were used to evaluate whether natal philopatry limits dispersal at multiple spatial scales. Ripley's K revealed that nests were significantly clustered at multiple scales, when both nesting sites were considered and within each nesting site. This suggests a patchy, nonrandom distribution of nests within nest sites. Hierarchical AMOVA revealed that nest‐site aggregations did not explain a significant portion of genetic variation within nesting sites. However, a small but positive correlation between geographic and genetic distance was detected using a Mantel's test. Hence, the relationship between geographic distance and genetic distance among hatchlings within nest sites, while detectable, was not strong enough to have a marked effect on fine‐scale genetic structure. Spatial and genetic data combined determined that the nesting sites included nesting females from multiple locations, and the hypothesis of “natal philopatry” was not supported because females nesting in the same cluster were no more closely related to each other than to other females from the same nesting site. These findings imply that nesting aggregations are more likely associated with cryptic habitat variables contributing to optimal nesting conditions.     

Female‐biased dispersal in a bat with a female‐defence mating strategy

The ultimate causes for predominant male‐biased dispersal (MBD) in mammals and female‐biased dispersal (FBD) in birds are still subject to much debate. Studying exceptions to general patterns of dispersal, for example, FBD in mammals, provides a valuable opportunity to test the validity of proposed evolutionary pressures. We used long‐term behavioural and genetic data on individually banded Proboscis bats (Rhynchonycteris naso) to show that this species is one of the rare mammalian exceptions with FBD. Our results suggest that all females disperse from their natal colonies prior to first reproduction and that a substantial proportion of males are philopatric and reproduce in their natal colonies, although male immigration has also been detected. The age of females at first conception falls below the tenure of males, suggesting that females disperse to avoid father–daughter inbreeding. Male philopatry in this species is intriguing because Proboscis bats do not share the usual mammalian correlates (i.e. resource‐defence polygyny and/or kin cooperation) of male philopatry. They have a mating strategy based on female defence, where local mate competition between male kin is supposedly severe and should prevent the evolution of male philopatry. However, in contrast to immigrant males, philopatric males may profit from acquaintance with the natal foraging grounds and may be able to attain dominance easier and/or earlier in life. Our results on Proboscis bats lent additional support to the importance of inbreeding avoidance in shaping sex‐biased dispersal patterns and suggest that resource defence by males or kin cooperation cannot fully explain the evolution of male philopatry in mammals.     

Polygynandry, extra-group paternity and multiple-paternity litters in European badger (Meles meles) social groups

The costs and benefits of natal philopatry are central to the formation and maintenance of social groups. Badger groups, thought to form passively according to the resource dispersion hypothesis (RDH), are maintained through natal philopatry and delayed dispersal; however, there is minimal evidence for the functional benefits of such grouping. We assigned parentage to 630 badger cubs from a high-density population in Wytham Woods, Oxford, born between 1988 and 2005. Our methodological approach was different to previous studies; we used 22 microsatellite loci to assign parent pairs, which in combination with sibship inference provided a high parentage assignment rate. We assigned both parents to 331 cubs at > or = 95% confidence, revealing a polygynandrous mating system with up to five mothers and five fathers within a social group. We estimated that only 27% of adult males and 31% of adult females bred each year, suggesting a cost to group living for both sexes. Any strong motivation or selection to disperse, however, may be reduced because just under half of the paternities were gained by extra-group males, mainly from neighbouring groups, with males displaying a mixture of paternity strategies. We provide the strongest evidence to date for multiple-paternity litters, and for the first time show that within-group and extra-group males can sire cubs in the same litter. We investigate the factors that may play a role in determining the degree of delayed dispersal and conclude that the ecological constraints hypothesis, benefits of philopatry hypothesis, and life history hypothesis may all play a part, as proposed by the broad constraints hypothesis.     

Genetic evidence for sex-biased dispersal in resident bottlenose dolphins (Tursiops aduncus)

In most mammals males usually disperse before breeding, while females remain in their natal group or area. However, in odontocete cetaceans behavioural and/or genetic evidence from populations of four species indicate that both males and females remain in their natal group or site. For coastal resident bottlenose dolphins field data suggest that both sexes are philopatric to their natal site. Assignment tests and analyses of relatedness based on microsatellite markers were used to investigate this hypothesis in resident bottlenose dolphins, Tursiops aduncus, from two small coastal populations of southeastern Australia. Mean corrected assignment and mean relatedness were higher for resident females than for resident males. Only 8% of resident females had a lower probability than average of being born locally compared to 33% of resident males. Our genetic data contradict the hypothesis of bisexual philopatry to natal site and suggest that these bottlenose dolphins are not unusual amongst mammals, with females being the more philopatric and males the more dispersing sex.     

Patterns and dynamics of sex-biased dispersal in a nocturnal primate, the grey mouse lemur, Microcebus murinus

We examined predictions on the proportion of dispersing natal males and females, dispersal distances, the age at dispersal and the potential for inbreeding over a 6-year period in a free-living population of grey mouse lemurs. We used monthly mark-recapture procedures to determine individual locations and interindividual distances. The analysis of seven polymorphic microsatellite markers for 213 (130 males, 83 females) individuals allowed us to estimate relatedness coefficients and kinship relationships. Closely related males ranged further from each other than closely related females and natal males were found further from their potential mothers than were females. Natal males were more likely to disperse from their birth sites than females, although male dispersal was not universal. Male breeding dispersal was detected in half of the long-term observations. Males therefore seem to be the predominant vectors for gene flow between populations and social units. Females usually stayed within one to two home range diameters of their potential mother, facilitating the evolution of cooperative behaviour by kin selection among females. Most dispersal took place before the mating season, indicating an age of less than 7 months for natal dispersal. The analysis of spatiotemporal coexistence revealed the potential for inbreeding in only 3.8% of the potential mother-son dyads, but in 21.9% of the potential father-daughter dyads and in 41.7% of other closely related male-female dyads. Copyright 2003 Published by Elsevier Science Ltd on behalf of The Association for the Study of Animal Behaviour      

Sex-biased survival and philopatry in birds: Do they interact?

A review of studies of sex-biased dispersal and philopatry and sex-biased survival in birds is presented. The comparison between sex-related mortality and natal and breeding dispersal at the species-level shows that dispersing birds (mainly females) suffer higher mortality, while philopatric birds (mainly males) have higher survival. The interaction between sex-biased survival and spatial behavior is a crucial component of avian vital strategy, which determine population dynamics and genetic structure.     

Dispersal, philopatry, and genetic relatedness in a social carnivore: comparing males and females

A balance must be maintained between the proportion of individuals dispersing and the proportion remaining philopatric such that inbreeding and resource competition are minimized. Yet the relative importance of dispersal and philopatric behaviour is uncertain, especially for species with complex social systems. We examine the influence of dispersal on genetic relationships of a white-nosed coati ( Nasua narica : Procyonidae) population from Panama. Field studies of the coati indicate a social system in which all females are highly philopatric and live in bands while all adult males become solitary at maturity, but do not disperse from the home range of their natal band. Based on analyses of multilocus DNA fingerprints, we confirm that female philopatry is the rule, long-distance dispersal is rare, and that relatedness between most bands is low. However, some new bands result from fission events and these bands retain relatively high relatedness to one another for several years. Adult males inhabiting the home range of a band are closely related to band members. In contrast, males and band members whose ranges do not overlap are unrelated or only slightly related. Adult males are also more closely related to other males whose home ranges they overlap extensively than to males whose home ranges they overlap only slightly. These results indicate that males initially disperse from their natal bands to reduce resource competition and not to avoid inbreeding. Inbreeding avoidance, if it occurs, results from more extensive range movements by males during the mating season.