Multiple mating is linked to social setting, and benefits the males in a communally rearing mammal

Individuals in social species may mate with multiple opposite sex individuals, including members of the same or different social groups. This variation may be linked to genetic benefits, where multiple mating decreases risk of inbreeding. Multiple mating also may be constrained by the socio-spatial setting through its effect on availability of mates. Since multiple mating with individuals from same or different groups may determine sex-specific fitness effects, we also examined how multiple mating modulates social benefits of females and males. We used 7 years of data on demography, social organization, and genetics of a natural population of the group-living and colonial rodent, Octodon degus, to determine how kin and sex composition within social groups, and spatial relations between these groups (i.e., colonial habits) influence multiple mating and its fitness consequences. 81.3% of males and 64.9% of females produced offspring with multiple opposite sex individuals within groups and...

群居物种的个体可与多个异性个体交配，其交配对象既包括同社交群体内的成员，也涵盖不同社交群体中的个体。此类交配行为的变异可能与遗传收益相关——多次交配能够降低近交（inbreeding）风险。同时，多次交配行为也可能受到社会空间环境的制约，该环境会通过影响潜在配偶的可获得性对交配行为施加限制。鉴于与同组或异组个体发生多次交配可能决定性别特异性的适合度（fitness）效应，本研究同时探讨了多次交配如何调控雌性与雄性的社交收益。本研究以群居集群啮齿动物八齿鼠（Octodon degus）的自然种群为研究对象，借助7年间收集的种群动态、社会组织结构及遗传学数据，探究社交群体内部的亲缘关系与性别组成，以及群体间的空间关联（即集群习性）如何影响多次交配行为及其适合度后果。81.3%的雄性个体与64.9%的雌性个体可在群体内与多个异性个体交配并产生后代，且……