Abstract # 115:

Scheduled for Friday, August 18, 2006 11:30 AM-11:45 AM: Session 10 (Regency East #2) Oral Presentation

Can face color look nice? Face coloration and heterosexual interactions in free-ranging male rhesus macaques (Macaca mulatta) in the mating season.

M. S. Gerald1,2, A. Accamando1,3, A. Weiss4, D. Seelig5,6 and J. Ayala1,2
1Cayo Santiago, Caribbean Primate Research Center, CPRC, PO BOX 906, Punta Santiago, PR 00741, USA, 2University of Puerto Rico, Medical Sciences Campus, 3National Institutes of Health, NICHD, Laboratory of Comparative Ethology, 4The University of Edinburgh, School of Philosophy, Psychology, and the Language Sciences, Department of Psychology, 5Department of Neuroscience, University of Pennsylvania, 6School of Veterinary Medicine, University of Pennsylvania
     Among many primate species males display conspicuous sex skin coloration. During the mating season, male and female rhesus macaques (Macaca mulatta) undergo increased face and hindquarter reddening. Experiments show that female rhesus gaze longer at images of males with artificially reddened faces over pale matched controls (Waitt et al. 2003). To determine whether females perceive color as attractive, threatening, or advertising male support, we examined face color and heterosexual interactions initiated by and directed toward 19 adult male rhesus during 860 observation hours over four months throughout the 2004 mating season on Cayo Santiago. When averaged across trials, face color was unrelated to rates of male threats or aggression, and females did not preferentially interact sexually or affiliatively with males based on color. To determine whether baseline levels or temporal changes in color were related to temporal social behavior changes, we used growth curve analysis. There was a significant effect (beta = -.987, p = .023) of the slope of facial luminosity on aid given to females, indicating that facial luminosity changes over time were inversely related to change over time in the amount of coalitionary support males offered females. These results suggest that, perhaps as an alternative mating strategy, males whose faces decrease in luminosity over the mating season are more likely to increase their amount of aid to females throughout this period.