Social complexity and kinship in animal societies

Abstract

Studies of eusocial invertebrates regard complex societies as those where there is a clear division of labour and extensive cooperation between breeders and helpers. In contrast, studies of social mammals identify complex societies as those where differentiated social relationships influence access to resources and reproductive opportunities. We show here that, while traits associated with social complexity of the first kind occur in social mammals that live in groups composed of close relatives, traits associated with the complexity of social relationships occur where average kinship between female group members is low. These differences in the form of social complexity appear to be associated with variation in brain size and probably reflect contrasts in the extent of conflicts of interest between group members. Our results emphasise the limitations of any unitary concept of social complexity and show that variation in average kinship between group members has far-reaching consequences for animal societies.

Rethinking animal social complexity measures with the help of complex systems concepts

“…It is short-sighted to expect that a single approach to complexity will capture all the relevant aspects of social complexity in all research contexts. Conceptualizing complexity along multiple axes helps circumvent some of the drawbacks of quantifying social complexity with a single measure, and a multidimensional approach to social complexity, for example as seen in some recent proposals [7,81], is likely to improve comparisons of social systems when taking a "different is interesting" descriptive approach. However, a persistent issue with multidimensional approaches is that if the separate axes of complexity do not individually reflect relevant measures of complexity, it is unlikely that looking at the combination of these measures will provide additional insight into social complexity, or a better description of the sociality.…”

“…Complex social systems are comprised of individuals that interact with many other individuals across different social contexts and over time (adapted from [4], see also [5]). Methods for studying animal social complexity vary widely in their approaches and are often divided into whether they focus on social relationships (more common for vertebrate systems) or on social organization and social roles (more common for social insect systems) [6,7]. The development of animal social complexity measures has been driven largely by what can be feasibly measured in animal societies.…”

Friend or foe: reconciliation between males and females in wild chacma baboons

“…Differences in avian and mammalian reconciliation behavior have been attributed not merely to the lower incidence of aggression in monogamous relationships, but to the fluidity of avian social systems which may facilitate post-conflict dispersal (Fraser & Bugnyar, 2011;Seed et al, 2007). Overall, reconciliation may be most frequent in societies with low average kinship among group members like those of promiscuous mammals, where conflicts of interests are common and require individuals to develop complex strategies to manage differentiated and fitnessenhancing relationships with non-kin (Lukas & Clutton-Brock, 2018).…”

Genetic similarity and facial cues for kin recognition in humans

“…Aside from its relationship to the evolution of cooperation (e.g. [23,22,25,43,29,4,19]), the ability to distinguish kin from non-kin may impact how social kinship is organized, how it evolves, and how mates are selected [32,30]. However, the genetic underpinnings of kin recognition have been largely understudied.…”