MaRGA Meeting, 2004: Abstracts

20: Physiology and Immunology

Getting Hormonal Data From Wild Common Marmoset Females:
New Insights About Immigration and Mating Systems Mechanisms

M.B. Sousa, A.C.S.R. Albuquerque, and H.M. Santos

Affiliation: Universidade Federal do Rio Grande do Norte, Natal, Brazil

The use of hormonal analysis in feces is a useful tool to investigate reproductive performance in wild primates. A two-step method to measure fecal progesterone was recently validated for captive common marmosets. These small primates live in secondary forests in the Northeastern region of Brazil and the major aspects related to their reproductive strategies have been clarified by the association between behavioral and hormonal studies. Despite the large hormonal information obtained from captive common marmosets no studies were developed until now for natural groups. Therefore the goals of this study were to determine the methodological concerns related to fecal collection under natural conditions and to establish the reproductive functioning of subordinate females in both situations: 1) before emigration from the natal group and, 2) when they were living in either monogamous and polygynous groups. We found that the chance to collect fecal samples is a 100% when it is done shortly after the animals wake up when they start their motor activities around their sleeping trees. Factors such as temperature, rainfall, pregnancy and parturition do not disrupt the sampling but retards slightly the time of the first defecation. Subordinate females emigrated from natal groups showing different reproductive conditions such as not ovulating, ovulating or even pregnancy and in one occasion we recorded emigration and return to natal group by one subordinate female when a reproductive vacancy appeared. Subordinate females were able to reproduce in both monogamous and polygynous groups but most in occasions they lost their infants. These data indicate that subordinate females when living in natural groups express different strategies trying to obtain their reproductive success.

MaRGA gratefully acknowledges the generous contribution of Harlan, Inc. in sponsoring this invited speaker.