DR. LISA GOULD, of the University of Victoria in Victoria, Canada, received funding in January 2001 to aid research on male stress and reproductive success in the ringtailed lemur, a female-dominant primate species. The costs and benefits to adult males of group living were investigated in three social groups of ringtailed lemurs at Beza Mahafaly Reserve, Madagascar. The physiological cost of group living was determined by examining individual variation in mean fecal cortisol levels, a hormonal indicator of stress, and relating the results to the age and dominance rank of each male, to mating versus nonmating periods, to the number of males in a group, and to rates of affiliative and aggressive behaviors between males and by females toward males. Fecal samples and behavioral data were collected in 2001 after the mating season and in 2003 during both the mating and the immediate postmating periods. Despite extreme intermale physical aggression and competition over access to receptive females during the mating season, no significant differences were found in mean fecal cortisol levels when mating and postmating data were compared. Neither age nor individual male dominance rank had any effect on mean cortisol levels. In 2001, males living in the group with the fewest males exhibited signficantly lower cortisol levels and higher rates of social interaction with females. In 2003, both affiliation with and aggression by females toward males was significantly higher in the mating season than afterward. Males in groups with fewer males appeared to experience less male-male competition over access to estrous females and were able to sequester receptive females more easily than could males living in the group with more males. For a ringtailed lemur male, living in a group with fewer males may be less stressful and more beneficial to reproductive success.
Post-Ph.D. Research Grant
Victoria, U. of
Gould, Dr. Lisa, U. of Victoria, Victoria, Canada - To aid research on 'Male Stress and Reproductive Success in the Ringtailed Lemur, a Female-Dominant Primate Species'