Does Male Care, Provided to Immature Individuals, Influence Immature Fitness in Rhesus Macaques?

• Published in: PloS one Vol. 10; no. 9; p. e0137841
• Main Authors: Langos, Doreen, Kulik, Lars, Ruiz-Lambides, Angelina, Widdig, Anja
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 14.09.2015; Public Library of Science (PLoS)
• Subjects: Adipose Tissue; Animal behavior; Animal reproduction; Animals; Babies; Behavior, Animal; Biology; Body fat; Body mass; Body size; Body Weight; Breeding success; Cynomys ludovicianus; Demographics; Editors; Fathers; Females; Fitness; Infants; Influence; Macaca mulatta - genetics; Macaca mulatta - physiology; Male; Males; Mammals; Mothers; Offspring; Organ Size; Paternity; Pharmacy; Primates; Protection and preservation; Puerto Rico; Reproduction; Reproductive fitness; Sexual Maturation; Studies; Success; Survival; Testis - growth & development; Puerto Rico; United States > US; Germany; Chicago Illinois
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0137841

Among many mammals, maternal care strongly impacts infant survival; however, less is known about whether adult males also affect infant fitness. Paternal care is expected when providing care enhances offspring survival and reproduction, which likewise increases fathers' fitness. Males might also care for unrelated immature individuals to increase their mating probability with the immature individuals' mothers. Studies in multimale primate groups showed that sires enhance food access for offspring and provide protection in conflicts. Furthermore, fathers' presence during infancy has been suggested to accelerate offspring sexual maturation. However, no study has yet directly linked the degree of father-offspring bonds to offspring fitness in primates. We previously reported father-offspring affiliation in rhesus macaques, pronounced during early infancy and independent of mothers' presence. The present study aims at investigating whether affiliation with fathers or other males affects proxies of immature fitness (body mass gain, body fat and testis size). First, we combined behavioral, genetic and morphometric data from 55 subjects of one group. Second, using demographic and genetic data, we investigated for 92 individuals of the population whether mother- and father-offspring co-residence during immaturity influenced offspring lifetime reproductive success (LRS). Our results show that focal rank and higher amounts of affiliation with high-ranking males during infancy tend to positively impact body mass gain of female, but not male focal animals. In contrast, body mass gain of male focal individuals, but not females', appeared to be higher when affiliation of male immature individuals was evenly distributed across their adult male partners. Moreover, we found mothers', but not fathers', presence during immaturity to predict offspring LRS. Our results suggest that male-immature affiliation, but not father-offspring co-residence, potentially impacts proxies of immature fitness. However, future studies should investigate the underlying mechanisms of male-immature relationships and their impact on immature fitness in more detail.