Doctoral Dissertation Research: Leaving home: genetic, endocrine, and behavioral correlates of dispersal in monogamous monkeys

University Of Pennsylvania, Philadelphia PA

Investigators

Abstract

In some primate species, it is common for individuals to leave the group in which they were born to join a different group (dispersal), but the evolutionary reasons dispersal are not completely understood. Primates exhibit high levels of inter- and intra-specific variation in dispersal, and there are costs associated with unfamiliar locations and/or aggressive competitors. Many models attempting to explain the evolution of dispersal have proposed a tight link among dispersal patterns, mating systems, and life history traits. Developing a better understanding of how social and mating systems influence and are influenced by dispersal patterns is essential for understanding the evolution of social and mating systems in primates, including humans. This project will study primate dispersal in a socially monogamous monkey species using genetic and hormone data collected non-invasively. This research is part of the Owl Monkey Project (OMP), a long-term initiative to promote research, conservation, and education in the Argentinean Chaco. Broader impacts include training of a female graduate student and undergraduate students in a STEM field, and support of international collaborations between the US and Argentina. In this dissertation project, the co-PI will examine genetic, endocrine, and behavioral correlates of dispersal in free-ranging, socially monogamous owl monkeys of the Argentinean Chaco. The project will explore dispersal at the level of the community by genetically sampling individuals, and at the level of the social group by examining hormones and behavior in subadult males and females. Specifically, it will utilize genotype data from ~250 owl monkeys, behavioral data from 22 predispersing subadults, and steroid hormone data from ~1000 fecal samples to address current debates over the relationships between mating system and dispersal by evaluating inbreeding and competition avoidance hypotheses. These genetic, behavioral, and hormonal data will also be used to evaluate the costs and benefits of delaying dispersal in groups where a variable number of close kin may be present. Genetic data from this project also have strong potential to elucidate how a bisexually dispersing species may utilize differences in the average distance dispersed by each sex to avoid potential costs of inbreeding. The unique multi-level approach and integrative nature of this study of natal dispersal in a socially monogamous species has potential to illuminate the origins of dispersal and mating patterns in pair-bonded primates, including humans.