Data from: 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 with individuals of neighboring groups. Thus, polygynandry was the
dominant mating system in the degu population examined. Multiple mating in
degus was high when compared with estimates reported in other social
mammals. Variation in female and male multiple mating was better explained
by social setting through its effect on availability of potential mates
rather than by benefits derived from decreasing risk of inbreeding.
Finally, our study revealed how multiple mating enhances male, but not
female reproductive success.