Low paternity skew and the influence of maternal kin in an egalitarian, patrilocal primate

Abstract

Levels of reproductive skew vary in wild primates living in multimale groups depending on the degree to which high-ranking males monopolize access to females. Still, the factors affecting paternity in egalitarian societies remain unexplored. We combine unique behavioral, life history, and genetic data to evaluate the distribution of paternity in the northern muriqui (Brachyteles hypoxanthus), a species known for its affiliative, nonhierarchical relationships. We genotyped 67 individuals (22 infants born over a 3-y period, their 21 mothers, and all 24 possible sires) at 17 microsatellite marker loci and assigned paternity to all infants. None of the 13 fathers were close maternal relatives of females with which they sired infants, and the most successful male sired a much lower percentage of infants (18%) than reported for the most successful males in other species. Our findings of inbreeding avoidance and low male reproductive skew are consistent with the muriqui's observed social and sexual behavior, but the long delay (≥2.08 y) between the onset of male sexual behavior and the age at which males first sire young is unexpected. The allocation of paternity implicates individual male life histories and access to maternal kin as key factors influencing variation in paternaland grandmaternal-fitness. The apparent importance of lifelong maternal investment in coresident sons resonates with other recent examinations of maternal influences on offspring reproduction. This importance also extends the implications of the "grandmother hypothesis" in human evolution to include the possible influence of mothers and other maternal kin on male reproductive success in patrilocal societies.mating system | reproductive strategy | development | molecular ecology | Platyrrhini

Howler Monkeys

“…Larger male groups may have been more attractive to females because they were more successful in defending food resources and/or allowed for increased mate choice opportunities. This increase in male and female group sizes and female mate choice reduced paternity skew Strier et al 2011 ) and extragroup copulations. Together, these changes signifi cantly reduced the potential advantages of infanticidal behavior.…”

Co–Residence between Males and Their Mothers and Grandmothers Is More Frequent in Bonobos Than Chimpanzees

“…Similarly, sons who associate strongly with their mothers in the patrilocal egalitarian northern Muriqui new world monkeys are among the most reproductively successful males [64]. Social dominance has a large effect on chimpanzee male reproductive success, and short–term reproduction is skewed [29,49,51].…”

Insights into Reproductive Strategies and Sexual Selection in Howler Monkeys

“…Larger male groups may have been more attractive to females because they were more successful in defending food resources and/or allowed for increased mate choice opportunities. This increase in male and female group sizes and female mate choice reduced paternity skew (Di Fiore et al 2009 ;Strier et al 2011 ) and extragroup copulations. Together, these changes signifi cantly reduced the potential advantages of infanticidal behavior.…”