Testosterone and behavior in female marmosets

This study examines the role of testosterone in mediating behavior in common marmosets (Callithrix jacchus) and across the primate order. Testosterone has been primarily studied in males. Male behaviors related to mating success (competition and finding mates) are positively associated with testosterone levels in many bird and mammalian species. Conversely, male testosterone is negatively associated with infant care. The relationship between mating effort and infant care may represent a trade-off with testosterone serving as one hormonal mediator of these behaviors. Because females also exhibit mating competition and must balance mating investment with caring for offspring, I explored whether testosterone varied with female behavior in similar patterns as seen in males. I used a captive colony of common marmosets, at the Southwest National Primate Research Center in San Antonio, TX. To control for social context, I examined the relationship between testosterone and behavior during staged intruder tests and without any social manipulation. I compared female and male behavior and testosterone concentrations using non-invasively collected fecal samples. Neither female nor male testosterone showed a statistically significant increase in response to intruders, but female testosterone concentrations were indistinguishable from those of males during intruder tests. To test whether investing in mating behavior represented a trade-off with infant care in captive common marmosets, I also compared general behavior patterns between sexes. Females and males engaged in similar amounts of time spent being aggressive, engaging in sexual behavior, and caring for offspring. However, male common marmosets exhibited a correlation between aggression and distance from infants, whereas females did not. This suggests that the trade-off between mating effort and infant care exists for males but not females in common marmosets. I also compared testosterone concentrations without social manipulation between females and males and found no difference in fecal testosterone concentrations. A comparison of the ratio of male-to-female testosterone was done across primates. Mean male:female testosterone concentrations correlated with mating system across primates. However, the comparative data set was small and more data are needed to fully explore the relationship of testosterone and behavior in primates. The idea that testosterone may mediate behavior in females has implications in the evolution of mating and parental behavior.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Anthropology

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2018

Author dc:creator

• Melber, Talia N.

Contributors dc:contributor

• Stumpf, Rebecca M.
• Clancy, Kathryn B.H.
• Malhi, Ripan
• Tardif, Suzette D.

• testosterone
• female testosterone
• common marmosets
• parenting
• mating effort
• challenge hypothesis
• sexual dimorphism
• primates
• intruder test

Statement dc:rights

• Copyright 2018 Talia Melber

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/101024

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/101024