Abstract
BackgroundNon-random associations within and among groups of social animals can provide valuable insight into the function of group living and the evolution of social behaviour. Damaraland mole-rats (Fukomys damarensis) demonstrate extremely high levels of reproductive skew, and dispersal is considered to be male-biased in onset and frequency, although asymmetry in dispersal distance is yet to be investigated. Dispersal may be positively correlated with increasing favourable environmental conditions, such as rainfall, however, the effects of ecological constraints on dispersal and colony fission–fusion dynamics have not previously been demonstrated on a spatial scale. Here we provide the first spatial population genetic study for this species. We investigated genetic structure in a population of Damaraland mole-rats from the southern Kalahari in South Africa over 3 years, combining observational dispersal data from mark-recapture with population genetic data to evaluate (1) sex-bias in frequency and distance of dispersal in this species, and (2) the effect of rainfall on fission–fusion dynamics of colonies.ResultsOur results demonstrate (1) that both males and females favour local dispersal but on rare occasions may disperse over distances greater than 400 m, (2) that males may disperse over greater distances than females, and (3) that males more frequently immigrate into established neighbouring colonies than females, who predominantly disperse by colony fission, i.e. multiple individuals “budding” from their native colony into a neighbouring territory, thereby establishing new colonies. Furthermore, our results demonstrate (4) elevated dispersal and colony fission in association with increased rainfall, supporting the hypothesis that rainfall may play a significant role in the maintenance and/or disruption of reproductive skew in Damaraland mole-rat populations.ConclusionThis study represents the first fine-scale spatial population genetic study in Damaraland mole-rats, and provides relevant insights into colony fission–fusion dynamics in a social and cooperatively breeding species.
Highlights
Non-random associations within and among groups of social animals can provide valuable insight into the function of group living and the evolution of social behaviour
Investigating non-random associations within and among groups of social animals is essential for understanding the function of group living and the evolution of social behaviour
Numerous population genetics studies have addressed the consequences of female philopatry, male dispersal and matrilineal structure for genetic differentiation between groups
Summary
Non-random associations within and among groups of social animals can provide valuable insight into the function of group living and the evolution of social behaviour. Mynhardt et al BMC Ecology and Evolution (2021) 21:221 geographical site, but rather by their social interactions, including affinities, antagonisms, hierarchy and kinship [1] Philopatry in these species would refer to fidelity to natal colony rather than to natal environment, and dispersal refers to movement and/or integration of individuals from one social group into another. Numerous population genetics studies have addressed the consequences of female philopatry, male dispersal and matrilineal structure for genetic differentiation between groups These include theoretical [4, 5] and empirical studies involving primates [6, 7]; bats [8, 9]; plateau pikas [10] and woodrats [11, 12]. Colony fission may occur when colonies reach a maximum size, producing two or more new colonies, as reported in diverse species including social spiders [16], army ants [17], naked mole-rats [18, 19], marmots [20, 21] and primates [22, 23]
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