Abstract # 136:

Scheduled for Saturday, June 21, 2008 10:15 AM-10:25 AM: Session 15 (Meeting Room 2DEF) Oral Presentation


S. Van Belle1, A. Estrada2, T. E. Ziegler3 and K. B. Strier4
1Department of Zoology, University of Wisconsin-Madison, Madison, WI, USA, 2Instituto de Biología, Universidad Nacional Autónoma de México, Mexico, 3National Primate Research Center, University of Wisconsin-Madison, 4Department of Anthropology, University of Wisconsin-Madison
     Investigating the relation between social and sexual behavior and hormone concentrations can advance our understanding of male and female reproductive strategies. We present the reproductive activity of two multimale-multifemale groups of black howler monkeys (Alouatta pigra) observed during a 14 month study in Palenque National Park, Mexico. A total of 231 fecal samples were collected from 4 parous females. Ovarian estradiol and progesterone profiles revealed an average (± SE) cycle length of 16.8 ± 2.5 days (N=12). We observed 81 copulations. Five involved three resident males mating with two extra-group females. Seven copulations were observed without collecting corresponding hormonal data. The remaining 69 copulations were mapped onto the ovarian profiles to evaluate the timing of sexual behavior relative to the timing of ovulation. Of these, 88% occurred during the periovulatory periods (N=17), defined as the day of ovulation ± 3 days. The day of ovulation was estimated as the first day of sustained elevation in progesterone levels. During 14 periovulatory periods, males and females formed consortships, lasting on average 2.88 ± 1.27 days. Males were responsible for maintaining close proximity and females solicited and copulated exclusively with their consort mates. Outside their consortships, two females copulated with the other resident male in their group. In black howler monkeys, reproductive strategies seem to include both female mate choice and male mate guarding.