MaRGA Meeting, 2004: Abstracts

15: Neuroscience / Communication / Behavior

Mating Systems in Marmosets: Data from Captive and Wild Groups

M.E. Yamamoto, A. Araújo, F.S. Albuquerque, M.B. Sousa, A.I. Alencar and M.F. Arruda

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

The mating system of callitrichids has been suggested to be monogamous, polygynous and polyandrous. In Callithrix jacchus, two breeding female, as well as one breeding female groups have been reported. Reproduction in female common marmosets is usually related to dominance status, which is reflected in agonistic behavior and ovarian function. Socially dominant females have been reported to receive submissive behavior from subordinates, while exhibiting normal ovulatory function, intra-group copulatory behavior, and term births resulting in surviving offspring. Subordinate females, however, receive aggressive behavior from dominants, while exhibiting reduced or absent ovulatory function, and little or no intra-group copulatory behavior, with rare occurrences of term births. The long term monitoring of wild Callithrix jacchus groups in Nizia Floresta, RN, Brazil, suggests that wild groups may have one or two breeding females, but some of the two-breeding female groups may be, in fact, monogamous. Subordinate females in these two groups differed regarding the permanence in the group after breeding, the number of surviving offspring and the mating partner. Data from our colony indicated that subordinate females may or may not fight for the dominant rank in their groups, and this reflects in their behavioral and hormonal profiles. We suggest that such variation in female-female social dominance relationships and the associated variation in the degree and reliability of fertility suppression may explain why free-living groups of common marmosets can exhibit either one or two breeding females. We also suggest that subordinate female marmosets can explore reproductive alternatives other than remaining infertile in their natal group while waiting for a breeding vacancy in a neighboring group or migrating.

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