White-faced capuchins (Cebus capucinus) live in social groups comprised of extensive networks of both maternal and paternal kin - a demographic circumstance that is rare among mammals, but one that accentuates the importance of evolved mechanisms of inbreeding avoidance. Research on how such primates develop reproductive aversion toward certain individuals, and not others, will improve our understanding of these mechanisms and the limits of kin recognition in highly social animals. This project also will provide comparative work that may contribute to understanding the origins of, and variation in, incest avoidance across human societies.
The research by doctoral student Irene Godoy (University of California, Los Angeles), under the supervision of Dr. Susan Perry, combines behavioral observation, genetics, and endocrinology to study mating behavior in the Lomas Barbudal population of wild capuchins in Costa Rica. These data will test the hypotheses that (a) early social familiarity, (b) phenotypic matching, or (c) the use of such cues as age proximity and adult male rank are the mechanisms by which individuals avoid mating with close relatives. Additional hypotheses regarding female versus male responsibility for behaviors that prevent inbreeding, and the importance of developmental aspects of co-socialization, also will be addressed.
Observational data will be collected on the behavior of 24 adult females. Fecal samples will be collected non-invasively for later extraction of DNA or steroid hormones to determine paternity and maternity of individuals, and to track changes in female reproductive phase. Laboratory analyses will take place at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.
Funding for this project will support training of research assistants and a multi-ethnic, first-generation Latina graduate student. Outreach presentations will be made at six local elementary schools in Costa Rica, promoting interest among the students in careers in science and encouraging conservation efforts to protect the highly endangered tropical dry forest environment.
This research project combines behavioral observation, genetics, and endocrinology to study mating behavior in the Lomas Barbudal population of wild capuchin monkeys (Cebus capucinus) in Costa Rica. The main objective of the project is to (1) determine the mechanism by which individuals avoid mating with close relatives. Hypotheses tested are (a) early social familiarity, (b) phenotypic matching, and (c) the use of such cues as age proximity and adult male rank. Additional hypotheses regarding female versus male responsibility for behaviors that prevent inbreeding, and the importance of developmental aspects of co-socialization, are also being addressed. 10-minute focal follows were conducted on 21 adult females and over 1,500 fecal samples were collected non-invasively for later extraction of steroid hormones to track changes in female reproductive phase. Preliminary results indicate that adult male rank and early spatial proximity to adult males during infancy are reliable indicators of paternal relatedness, while age proximity is a moderately good indicator of paternal sibship. Analyses are ongoing to see whether adult females use these cues or other mechanisms, such as phenotypic matching, to assess relatedness to other group members, particularly in the context of mate choice. This project has provided internships for eight field assistants and provided project support for a first-generation Latina PhD student. The Co-PI has given scientific presentations to local Costa Rican forest service personnel and local Costa Rican youth.
