THE PAIR-BOND FORMATION AND ITS ROLE IN THE STIMULATION OF REPRODUCTIVE FUNCTION FEMALE COMMON MARMOSETS (CALLITHRIX-JACCHUS)

The sociosexual relationship between male and female common marmosets (Callithrix jacchus) is characterized by pair-bond formation, which in cludes sexual and social interactions such as contact, huddling and al logrooming. The formation of heterosexual pairs in captivity sometimes is unsuccessful in terms of reproduction. We investigated the existen ce of a correlation between characteristics of sociosexual interaction of marmoset pairs and its role in stimulating reproductive function i n females. We studied pair-bond formation during the first 10 weeks of pairing in eight unrelated heterosexual pairs of common marmosets (Ca llithrix jacchus) without prior sexual experience. In three of them, p regnancy occurred during the study period (group SR), and we compared the profile of their sociosexual interactions with that of the five ot her couples in which pregnancy was not registered (group NS) during th at period. The results show differences between the two groups, relate d mainly to affiliative responses between male and female, with signif icantly higher levels of allogrooming and simultaneous piloerection in the SR group, Although we did not find significant differences in the frequency of mounting behavior between groups, their reproductive suc cess was different, suggesting that some behavioral patterns related t o cooperative interactions between the male and female could be expres sing the pair-bond. These behaviors may be influencing the females' ph ysiology and consequently successful reproduction in the species.