title: Does Male Care, Provided to Immature Individuals, Influence Immature Fitness in Rhesus Macaques?
abstract: 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.
authors.affiliation: Junior Research Group of 'Primate Kin Selection', Department of Primatology, Max-Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103, Leipzig, Germany; Institute of Biology, Faculty of Bioscience, Pharmacy and Psychology, University of Leipzig, Talstrasse 33, 04103, Leipzig, Germany.
authors.forename: Doreen
authors.initials: D
authors.lastname: Langos
authors.affiliation: Junior Research Group of 'Primate Kin Selection', Department of Primatology, Max-Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103, Leipzig, Germany; Institute of Biology, Faculty of Bioscience, Pharmacy and Psychology, University of Leipzig, Talstrasse 33, 04103, Leipzig, Germany.
authors.forename: Lars
authors.initials: L
authors.lastname: Kulik
authors.affiliation: Junior Research Group of 'Primate Kin Selection', Department of Primatology, Max-Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103, Leipzig, Germany; Institute of Biology, Faculty of Bioscience, Pharmacy and Psychology, University of Leipzig, Talstrasse 33, 04103, Leipzig, Germany; Caribbean Primate Research Center, University of Puerto Rico, Medical Sciences Campus, PO Box 906, Punta Santiago, PR, 00741, United States of America.
authors.forename: Angelina
authors.initials: A
authors.lastname: Ruiz-Lambides
authors.affiliation: Junior Research Group of 'Primate Kin Selection', Department of Primatology, Max-Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103, Leipzig, Germany; Institute of Biology, Faculty of Bioscience, Pharmacy and Psychology, University of Leipzig, Talstrasse 33, 04103, Leipzig, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Widdig
mesh_terms: D000273:Adipose Tissue; D000818:Animals; D001522:Behavior, Animal; D001835:Body Weight; D005220:Fathers; D008253:Macaca mulatta / Q000235:genetics / Q000502:physiology*; D008297:Male; D009035:Mothers; D009929:Organ Size; D011647:Puerto Rico; D012741:Sexual Maturation; D013737:Testis / Q000254:growth & development