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Female Dyads (female + dyad)
Selected AbstractsComponents of Relationship Quality in ChimpanzeesETHOLOGY, Issue 9 2008Orlaith N. Fraser A novel approach to studying social relationships in captive adult chimpanzees (Pan troglodytes) was taken by using principal components analysis (PCA) to extract three key components of relationship quality from nine behavioural variables. Based on the loadings of the behavioural variables, the components appeared to match previously hypothesized critical aspects of social relationships and were therefore labelled Value, Compatibility and Security. The effects of kinship, sex combination, age difference and time spent together on each of the relationship quality components were analysed. As expected, kin were found to have more valuable, compatible and secure relationships than non-kin. Female,female dyads were found to be more compatible than male,male or mixed-sex dyads, whereas the latter were found to be most secure. Partners of a similar age were found to have more secure and more valuable relationships than those with a larger age gap. Individuals that were together in the group for longer were more valuable and more compatible, but their relationships were found to be less secure than individuals that were together in the group for a shorter time. Although some of the results may be unexpected based on chimpanzee socio-ecology, they fit well overall with the history and social dynamics of the study group. The methods used confer a significant advantage in producing quantitative composite measures of each component of relationship quality, obtained in an objective manner. These findings therefore promote the use of such measures in future studies requiring an assessment of the qualities of dyadic social relationships. [source] Spatial Association in a Highly Inbred Ungulate Population: Evidence of Fine-Scale Kin RecognitionETHOLOGY, Issue 2 2008Jorge Cassinello We present the first evidence of fine-scale kin recognition, based on a continuous measure of relatedness, in ungulates. The spatial association between herdmates of a captive population of aoudad (Ammotragus lervia), where all the individuals are related, is analysed during resting time. Our goal was to estimate which factors influence individuals' associations. The study population is highly inbred, although it does not show serious deleterious effects caused by consanguinity. It comprises a single captive herd, reproducing freely and in good conditions for more than 10 yr. It emerges that kin, measured as the coefficient of relationship between two given herdmates, is the main factor determining the spatial association (e.g. average distance) of male,male and female,female dyads, as more-related individuals tend to rest closer to each other than less-related ones. As for male,female dyads, individuals of a similar age tend to stay closer. To rule out any familiarity confounding effects, individuals' cohabitation time in the herd was added as a random factor in the analyses. Concerning the type of dyad, mother,calf dyads are characterized by higher proximity than others, particularly during the suckling period, whereas males tend to stay closer to each other than females or male,female dyads, being also more kin-related. Female social rank does not influence spatial association between herdmates. These results are related to group composition of the species in the wild, which are characterized by intense mother,calf bonds and all-male groups that are probably kin-related. It is seen that adult male,female associations are not related to kinship, but to age similarity, which is in accord with the assumption that main family groups in the wild are formed by matrilineal lines, whereas males are the dispersing sex. [source] Sex-biased natal dispersal and inbreeding avoidance in American black bears as revealed by spatial genetic analysesMOLECULAR ECOLOGY, Issue 21 2008CECILY M. COSTELLO Abstract We tested the hypothesis that sex-biased natal dispersal reduces close inbreeding in American black bears, a solitary species that exhibits nearly complete male dispersal and female philopatry. Using microsatellite DNA and spatial data from reproductively mature bears (, 4 years old), we examined the spatial genetic structure of two distinct populations in New Mexico from 1993 to 2000. As predicted, relatedness (r) and the frequency of close relationships (parent,offspring or full siblings) decreased with distance among female dyads, but little change was observed among male or opposite-sex dyads. Neighbouring females were more closely related than neighbouring males. The potential for inbreeding was low. Most opposite-sex pairs that lived sufficiently close to facilitate mating were unrelated, and few were close relatives. We found no evidence that bears actively avoided inbreeding in their selection of mates from this nearby pool, as mean r and relationship frequencies did not differ between potential and actual mating pairs (determined by parentage analysis). These basic patterns were apparent in both study areas despite a nearly two-fold difference in density. However, the sex bias in dispersal was less pronounced in the lower-density area, based on proportions of bears with male and female relatives residing nearby. This result suggests that male bears may respond to reduced competition by decreasing their rate or distance of dispersal. Evidence supports the hypothesis that inbreeding avoidance is achieved by means of male-biased dispersal but also indicates that competition (for mates or resources) modifies dispersal patterns. [source] Patterns of relatedness and parentage in an asocial, polyandrous striped hyena populationMOLECULAR ECOLOGY, Issue 20 2007AARON P. WAGNER Abstract We investigated patterns of relatedness and reproduction in a population of striped hyenas in which individuals are behaviourally solitary but form polyandrous spatial groups consisting of one adult female and multiple adult males. Group-mate males were often close relatives, but were unrelated or distantly related in some cases, indicating that male coalitions are not strictly a result of philopatry or dispersal with cohorts of relatives. Most male,female pairs within spatial groups were unrelated or only distantly related. Considering patterns of relatedness between groups, relatedness was significantly higher among adult males living in non-neighbouring ranges than among neighbouring males. Mean relatedness among male,female dyads was highest for group-mates, but relatedness among non-neighbouring males and females was also significantly higher than among dyads of opposite-sex neighbours. Female,female relatedness also increased significantly with increasing geographic separation. These unusual and unexpected patterns may reflect selection to settle in a nonadjacent manner to reduce inbreeding and/or competition among relatives for resources (both sexes), or mates (males). Finally, resident males fathered the majority of the resident female's cubs, but extra-group paternity was likely in 31% of the cases examined, and multiple paternity was likely in half of the sampled litters. [source] Kinship and social bonds in female chimpanzees (Pan troglodytes)AMERICAN JOURNAL OF PRIMATOLOGY, Issue 10 2009Kevin Langergraber A large body of theoretical and empirical research suggests that kinship influences the development and maintenance of social bonds among group-living female mammals, and that human females may be unusual in the extent to which individuals form differentiated social relationships with nonrelatives. Here we combine behavioral observations of party association, spatial proximity, grooming, and space use with extensive molecular genetic analyses to determine whether female chimpanzees form strong social bonds with unrelated individuals of the same sex. We compare our results with those obtained from male chimpanzees who live in the same community and have been shown to form strong social bonds with each other. We demonstrate that party association is as good a predictor of spatial proximity and grooming in females as it is in males, that the highest party association indices are consistently found between female dyads, that the sexes do not differ in the long-term stability of their party association patterns, and that these results cannot be explained as a by-product of the tendency of females to selectively range in particular areas of the territory. We also show that close kin (i.e. mother,daughter and sibling dyads) are very rare, indicating that the vast majority of female dyads that form strong social bonds are not closely related. Additional analyses reveal that "subgroups" of females, consisting of individuals who frequently associate with one another in similar areas of the territory, do not consist of relatives. This suggests that a passive form of kin-biased dispersal, involving the differential migration of females from neighboring communities into subgroups, was also unlikely to be occurring. These results show that, as in males, kinship plays a limited role in structuring the intrasexual social relationships of female chimpanzees. Am. J. Primatol. 71:840,851, 2009. © 2009 Wiley-Liss, Inc. [source] Scream,embrace displays in wild black-horned capuchin monkeysAMERICAN JOURNAL OF PRIMATOLOGY, Issue 6 2008Jessica Lynch Alfaro Abstract Reintroduction of capuchin monkeys (Cebus apella) into their social group in captivity can elicit sirena screams and embraces. Captive scream,embrace displays are male biased, and females never perform sirena screams. One hypothesis is that scream,embrace displays serve a tension-reduction or reconciliatory function between males with conflicting interests. Alternatively, these displays may function to maintain strong affiliative bonds between friendly male dyads. Scream and/or embrace displays in wild Brazilian black-horned capuchins were analyzed for social and ecological contexts, behavioral components, and individuals involved. Seventy-two displays were observed during the 199-day study period. Among the 66 displays for which both members could be identified by sex, there were 42 occurrences of male,male dyads, 17 of male,female dyads, and seven of female,female dyads. Scream,embrace dyads were male,male pairs significantly more often than expected from group membership, and the , male was the only male to engage in scream,embrace displays with females. Female,female pairs did embrace, but never emitted sirena screams. Displays most commonly occurred in "reunion" contexts, primarily the reuniting of subgroups after hours or days out of contact, but also after intergroup encounters, and across groups in "intergroup" displays. Displays were rare, but socially contagious, and subgroup reunions could elicit multiple displays in rapid succession. Although the occurrence of screams and embraces was positively correlated, both behaviors also occurred independently, and their functions may be different. Male sirena screams may be honest advertisements of united alliances, directed toward a third party, whereas the embrace may be a risky affiliative signal, directed primarily within the dyad. Am. J. Primatol. 70:551,559, 2008. © 2008 Wiley-Liss, Inc. [source] | ||||||||||