The ties that bind: Genetic relatedness predicts the fission and fusion of social groups in wild African elephants
Many social animals live in stable groups. In contrast, African savannah elephants (Loxodonta africana) live in unusually fluid, fission–fusion societies. That is, ‘core’ social groups are composed of predictable sets of individuals; however, over the course of hours or days, these groups may temporarily divide and reunite, or they may fuse with other social groups […]
Where sociality and relatedness diverge: the genetic basis for hierarchical social organization in African elephants
Hierarchical properties characterize elephant fission–fusion social organization whereby stable groups of individuals coalesce into higher order groups or split in a predictable manner. This hierarchical complexity is rare among animals and, as such, an examination of the factors driving its emergence offers unique insight into the evolution of social behaviour. Investigation of the genetic basis […]
Dispersed male networks in western gorillas
Although kin-selection theory has been widely used to explain the tendency of individuals to bias beneficial behaviors towards relatives living within the same social group [[1]], less attention has focused on kin-biased interactions between groups. For animal societies in which females emigrate, as is the case for mountain gorillas (Gorilla beringei beringei), encounters between males […]
Association patterns of African elephants in all-male groups: the role of age and genetic relatedness
Strong social bonds are uncommon among male mammals. In many mammals, however, males form all-male groups, providing opportunities for male-male bonds to emerge. We examined association patterns of male African elephants, Loxodonta africana, in all-male groups and assessed the influence of age and genetic relatedness on these associations. We also examined the influence of age […]
Preference for related mates in the fruit fly, Drosophila melanogaster
Although inbreeding is known for its negative consequences, recent theory predicts that inclusive fitness gains from inbreeding should outweigh the costs of inbreeding depression in many situations, resulting in optimal fitness from mating with intermediate relatives (optimal inbreeding). Consistent with this theory, in a previous field study on Drosophila melanogaster, we found that males were […]
Is sentinel behaviour safe? An experimental investigation
Sentinel behaviour, where individuals take turns to watch for danger and give alarm calls to approaching predators, has been observed in a number of animal societies. However, the evolutionary causes of this behaviour remain unclear. There are two main, competing hypotheses regarding the evolution of sentinel behaviour. The first hypothesis is that it is a […]
Fitness consequences of sibling egg cannibalism by neonates of the Colorado potato beetle, Leptinotarsa decemlineata
Egg cannibalism is a widely observed behaviour in nature that provides nutritional benefits without the costs of subduing prey. However, when egg cannibalism involves sibling eggs, the benefits obtained must balance inclusive fitness losses. Neonates of the Colorado potato beetle, Leptinotarsa decemlineata, readily consume other eggs within their natal clutch. To explore the fitness consequences […]
Ontogeny and symmetry of social partner choice among free-living yellow-bellied marmots
Affiliative interactions have important fitness consequences for individuals. Yet, precisely how social roles emerge across ontogeny outside of the context of agonistic interactions is largely unknown, particularly in free-living species of nonprimates. Here we used longitudinal data on yellow-bellied marmots, Marmota flaviventris, residing around the Rocky Mountain Biology Laboratory in Colorado, U.S.A., to investigate the […]