Behavioral strategies and hormonal profiles of dominant and subordinate common marmoset (Callithrix jacchus) females in wild monogamous groups

Abstract

New insights into the mating systems of common marmosets suggest that they are mainly monogamous, although polygyny and polyandry occasionally occur. Long-term monitoring of wild common marmosets has shown that some reports of polygynous groups (i.e., groups that contain more than one reproducing female) in fact indicate an unbalanced reproductive output associated with extragroup copulation. In this study we describe the behavioral and hormonal profiles of common marmoset (Callithrix jacchus) females living in three wild monogamous groups (Q, PBf, and T), varying from five to 11 individuals, at Nísia Floresta field station, RN, Brazil. The mating system of the groups was previously characterized in terms of affiliative, sexual, and mate-guarding behaviors. Behavioral data were collected once a week, and fecal samples were collected at least twice a week for 10-16 months, depending on the group. A preferential allogrooming relationship was recorded between dominant males and females. Under field conditions the reproductive inhibition of subordinate females appears to be more behavioral than hormonal, since subordinate females of the three groups ovulated and two conceived during the study. In these cases, the subordinate and dominant females reproduced 1 month apart, and infanticide (one case confirmed and one suspected) appeared to be part of the reproductive strategy of dominant females. Following the infanticide, ovarian inhibition (group T) or emigration and return to the natal group (group PBf) were observed. In the third group (Q) the subordinate female showed hormonal profiles compatible with pregnancy, but no infants were seen. These findings reflect the different alternatives that wild subordinate common marmoset females use to reproduce.

Four Breeding Females in a Free-Ranging Group of Buffy-Headed Marmosets (Callithrix flaviceps)

“…Although 2 breeding females have been reported in some free-ranging marmoset groups ( C. jacchus [Digby and Ferrari, 1994;Sousa et al, 2005], C. aurita [Coutinho and Corrêa, 1995], and C. penicillata [Decanini, 2006], C. flaviceps is the only callitrichid in which 3 or more females have been observed breeding in the same group. Long-term monitoring of a C. flaviceps group [Ferrari and Diego, 1992;Guimarães, 1998b] also revealed a shift from a single-female system, which lasted a number of years, to a multiple-female system involving 3 individuals.…”

“…Cycling in subordinates may thus be dependent on a number of criteria, such as the presence of potential mates and an adequate number of helpers. In turn, tolerating limited reproductive success in subordinates may be advantageous for the dominant female by maintaining potential helpers in the group [Sousa et al, 2005]. This paper reports on multiple breeding females in a free-ranging group of buffy-headed marmosets (Callithrix flaviceps) in south-eastern Brazil.…”

“…In most cases, groups also contain non-breeding adult females, suggesting that the mechanisms which inhibit reproduction in subordinates continue to function at some level. An additional trend is reduced reproductive success in subordinate breeding females [Coutinho and Corrêa, 1995;Guimarães, 1998b;Sousa et al, 2005]. Subordinate females typically have fewer and smaller litters than dominants, and a smaller proportion of their infants survive.…”

“…While reproduction is limited to this female in most social groups, due to the physiological suppression of ovulation in subordinates [Abbott, 1986], studies at a growing number of sites have reported the presence of a second breeding female in many social groups. In some populations of the common marmoset (Callithrix jac-Folia Primatol 2010;81:31-40 32 Hilário /Ferrari chus), groups with 2 breeding females are in the majority [Digby and Ferrari, 1994;Sousa et al, 2005], whereas in golden lion (Leontopithecus rosalia) or saddle-back (Saguinus fuscicollis) tamarins, a second breeding female may be present in only around 10% of groups [Dietz and Baker, 1993;Goldizen et al, 1996]. In most cases, groups also contain non-breeding adult females, suggesting that the mechanisms which inhibit reproduction in subordinates continue to function at some level.…”

Computational Approaches as a Tool to Study Developmental Biology in New World Primates

“…They live in freeranging groups composed of between 5-17 different-aged individuals, including adult males and females (Rylands, 2006;Araujo, 1996). They exhibit a flexible mating system, depending on ecological constraints, showing that common marmosets are preferentially monogamous but on some occasions a polygynous system may arise Sousa et al, 2005). Both mature and immature males and females emigrate from the natal group to build new social units, but this behavior is more frequent in females ).…”