Abstract
Information on the genetic structure of animal populations can allow inferences about mechanisms shaping their social organization, dispersal, and mating system. The mongooses (Herpestidae) include some of the best‐studied mammalian systems in this respect, but much less is known about their closest relatives, the Malagasy carnivores (Eupleridae), even though some of them exhibit unusual association patterns. We investigated the genetic structure of the Malagasy narrow‐striped mongoose (Mungotictis decemlineata), a small forest‐dwelling gregarious carnivore exhibiting sexual segregation. Based on mtDNA and microsatellite analyses, we determined population‐wide haplotype structure and sex‐specific and within‐group relatedness. Furthermore, we analyzed parentage and sibship relationships and the level of reproductive skew. We found a matrilinear population structure, with several neighboring female units sharing identical haplotypes. Within‐group female relatedness was significantly higher than expected by chance in the majority of units. Haplotype diversity of males was significantly higher than in females, indicating male‐biased dispersal. Relatedness within the majority of male associations did not differ from random, not proving any kin‐directed benefits of male sociality in this case. We found indications for a mildly promiscuous mating system without monopolization of females by males, and low levels of reproductive skew in both sexes based on parentages of emergent young. Low relatedness within breeding pairs confirmed immigration by males and suggested similarities with patterns in social mongooses, providing a starting point for further investigations of mate choice and female control of reproduction and the connected behavioral mechanisms. Our study contributes to the understanding of the determinants of male sociality in carnivores as well as the mechanisms of female competition in species with small social units.
Highlights
The social organization of vertebrates is defined by the composition of species-specific social units with regard to the number of individuals, their sex, age, cohesion, and the resulting genetic structure (Kappeler and van Schaik 2002)
Ecology and Evolution published by John Wiley & Sons Ltd
We aimed to clarify whether (1) there are population-wide sex differences in haplotype distribution and relatedness, (2) the higher observed rate of male dispersal was reflected by greater haplotype diversity, (3) members of male and female social units were more closely related to each other than expected by chance, and (4) to characterize the genetic mating system and the level of reproductive skew in both sexes
Summary
The social organization of vertebrates is defined by the composition of species-specific social units with regard to the number of individuals, their sex, age, cohesion, and the resulting genetic structure (Kappeler and van Schaik 2002). Behavioral and demographic data can be used to describe how individuals are distributed in space and time, and solitary, pair-living, and group-living species are recognized as fundamental units of categorization of interspecific variation in social organization (Crook 1970). The resulting genetic structure of a given population and, in particular, the relatedness within and among social groups is not straightforward to predict from a particular type of social organization, because species vary in sexspecific reproductive skew and dispersal pattern, adult sex ratio and other demographic characteristics (Greenwood 1980; Nonacs and Hager 2011; Di Fiore 2012; Liker et al 2013; Nidiffer and Cortes-Ortiz 2015).
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