Abstract # 88:

Scheduled for Thursday, June 18, 2015 06:00 PM-08:00 PM: (Cascade AJBCD) Poster Presentation


T. N. Melber1, K. B. Clancy1, S. D. Tardif2,3 and R. M. Stumpf1
1Department of Anthropology, University of Illinois, Urbana-Champaign, 607 S. Mathews Ave., Urbana, IL 61801, USA, 2Southwest National Primate Research Center, Texas Biomedical Research Institute, 3Barshop Institute for Longevity and Aging Studies, University of Texas Health Sciences Center
     Marmosets are unusual in that they invest in mating effort while providing parental care. Males rely on testosterone to shift their behavioral focus between mating competition and paternal care, yet little is known about how the competing demands of mating and parenting are mediated in females. Given the importance of shifting energetic priorities from mating to parenting, testosterone may also mediate this trade-off in females. We compare male and female behavioral and hormonal response to intruders. We hypothesize that both sexes will react aggressively toward intruders, have similar testosterone levels, and that testosterone will correlate with aggressive and sexual behaviors. Fecal samples were collected from six breeding pairs of marmosets and assayed for testosterone using EIA. Behavior during intruder tests was videotaped and scored using continuous data collection. We found no significant difference between male and female rates of aggression directed at intruders (t = 1.78, p = 0.11). Baseline testosterone levels were similar between males and females (t = 0.93, p = 0.39). Test day hormone samples positively correlated with the percent time spent displaying aggressive behavior toward the intruder group (Spearman's r = 0.583, p = 0.05, one-tailed). Our results show that female marmosets engage in mating competition at similar levels to males and exhibit reduced hormonal dimorphism, suggesting that females respond to evolutionary pressures in a similar manner as males.