Fecal androgen levels in common marmoset (Callithrix jacchus) males living in captive family groups

Abstract

In captive common marmoset groups, the reproductive inhibition observed in subordinate female seems to be a result of olfactory, visual and behavioral cues from the dominant female. However, few studies have examined the relationship among adult males living in the same social group. These studies have shown that reproductive failure among peer males seems to be based on hormonal and behavioral mechanisms. New insights on sexual strategies in primates have been shown using fecal steroids, but so far no information is available for common marmoset males. In the present study, we evaluated the influence of light-dark cycle, age and reproductive condition on the profile of fecal androgens in males living in the same family group. Feces were collected from six fathers and six sons for androgen determination during the light phase of the 24-h cycle for eight days randomly distributed over a 4-week period. Androgen levels were determined by enzyme immunoassay technique. Adult sons showed higher androgen levels (166.97 ± 22.95 ng/g) than fathers (80.69 ± 44.38 ng/g) and juveniles (49.06 ± 23.15 ng/g; P < 0.05). No diurnal variation (P > 0.05) in fecal androgen profile was observed in adults or juveniles. No indication of androgen-mediated social competition between fathers and adult sons was demonstrable. These results provide basic information on fecal androgen profile useful to investigate the socioendocrinology of free-ranging common marmoset males and verify that, in contrast to daughters, the reproductive suppression of sons is not based on physiological inhibition of their gonads.

Social and developmental influences on urinary androgen levels in young male white‐faced marmosets (Callithrix geoffroyi)

“…Thus, the general patterns and hallmarks of androgen production in callitrichines mirror those of other primate groups. Yet, there is no evidence to suggest that there is active suppression of reproductive endocrine systems in callitrichine sons that remain in their natal group [Baker et al, 1999; Castro & Sousa, 2005; Ginther et al, 2002; Huck et al, 2005], in contrast to the well‐documented phenomenon of reproductive suppression in callitrichine daughters [Abbott, 1984; Abbott & Hearne, 1978; Abbott et al, 1988; Albuquerque et al, 2001; Barrett et al, 1990; Bercovitch & Ziegler, 2002; French et al, 1984; Saltzman et al, 1997, 2004; Widowski et al, 1992; Ziegler et al, 1987; reviewed in Abbott et al, 1998; French, 1997; Vandenbergh, 1989].…”

Testicular Volume and Reproductive Status of Wild Callithrix jacchus

“…Abbott (1984) also found no difference between plasma testosterone levels of unrelated dominant and subordinate males. Castro and Sousa (2005) described a significant increase in the basal levels of fecal androgen excretion in adult sons vs. their fathers when mothers were pregnant. Baker et al (1999) and Castro and Sousa (2005), respectively, suggested that the similar and higher testosterone levels in adult sons might be an adaptation to being aroused by the presence of a probable mate during intergroup encounters in wild conditions, increasing the opportunity for subordinates to copulate.…”

“…Castro and Sousa (2005) described a significant increase in the basal levels of fecal androgen excretion in adult sons vs. their fathers when mothers were pregnant. Baker et al (1999) and Castro and Sousa (2005), respectively, suggested that the similar and higher testosterone levels in adult sons might be an adaptation to being aroused by the presence of a probable mate during intergroup encounters in wild conditions, increasing the opportunity for subordinates to copulate. Long-term data from field studies Castro and Araújo 2004;Lazaro-Perea et al 2000;Lazaro-Perea 2001) have reinforced this theory, because free-ranging nonbreeding common marmosets copulate with females from neighboring groups during or immediately after encounters along home-range borders.…”

Social interactions and androgens levels in marmosets (Callithrix jacchus) in field and laboratory studies: A preliminary investigation of the Challenge Hypothesis

“…Studies in captivity have also shown that reproductive males experience a decrease in androgens when living in captive family groups with pregnant females. As such, in this reproductive phase, adult sons have higher androgen levels than those of their fathers (Castro and Sousa, 2005). According to Abbott (1984) male subordinates or male offspring are suppressed or prevented from exhibiting sexual behavior.…”