An investigation into sexual motivation and behavior in female Goeldi's monkey (Callimico goeldii): effect of ovarian state, mate familiarity and mate choice

Describing ovarian cycles, pregnancy characteristics, and the use of contraception in female white-faced marmosets, Callithrix geoffroyi

Endocrine data and characteristics of nonconceptive ovarian cycling and pregnancy are limited within the genus Callithrix to the common marmoset (C. jacchus) and Wied's black tufted-ear marmoset (C. kuhlii). This article presents patterns of urinary pregnanediol-3-glucuronide (PdG) excretion, as determined by enzyme immunoassay, throughout the course of ovarian cycling and pregnancy in white-faced marmosets (C. geoffroyi). Furthermore, characteristics of reproductive parameters including litter size, duration of gestation, maternal age, and information about ovarian cycling following administration of contraceptives are also described. A steep increase in PdG, an indication of ovulation, characterizes normative ovarian cycles, with peak-to-peak intervals between cycles being 27.82 ± 1.49 days in length. PdG excretion (μg/mg Cr) across pregnancy peaked during the 1st and 2nd trimesters (1st = 20.71 ± 2.98, 2nd = 21.16 ± 2.60) and declined gradually to near preconception levels over the 3rd trimester until parturition (3rd = 5.74 ± 1.60). Gestation lasted 148.55 ± 1.89 days. Most pregnancies (82.8%) resulted in an immediate postpartum ovulation (PPO) of 17.45 ± 2.22 days with 58.3% of PPOs resulting in conception. No differences in PdG excretion during the 1st trimester between full pregnancies and miscarriages were found, and pregnancy characteristics such as litter size, duration of gestation, and maternal age were not associated with PdG concentrations. Administration of cloprostenol resulted in shorter peak-to-peak cycle durations, but ovulation was detectable with similar concentrations of peak PdG to a normal nonconceptive cycle. Conversely, medroxyprogesterone acetate (DMPA) injections resulted in little to no PdG excretion across the ovarian cycle. Both methods of contraception providing effective prevention of conception. Overall, these results show that strong similarities in reproductive parameters persist within the genus Callithrix and to a lesser extent across the Callitrichidae family.

Different ovarian responses to potential mates underlie species-specific breeding strategies in common marmoset and Goeldi's monkey

Callitrichids are cooperative breeders, characterized by obligate twinning, extensive paternal care, and monopolization of reproduction by the dominant female. This is the case in the common marmoset, and in common marmoset groups of more than one adult female, subordinate females are typically acyclic consistent with infertility. However, one callitrichid, Goeldi's monkey, gives birth to singletons and exhibits low paternal care. Given these reproductive traits of Goeldi's monkey, we hypothesized that there would not be suppression of ovarian activity. To test this hypothesis, we applied non-invasive endocrine methods in a step-wise experiment with laboratory groups of both species. In each species, six pairs of sisters were studied alone, in visual contact with an unrelated male and in a polygynous trio with the male, and urine samples were collected for determination of oestrogen titres reflecting ovarian activity. Common marmoset sister pairs exhibited a marked difference in social status: during the study 5 of 6 dominant females conceived but only 1 of 6 subordinate females; the remaining 5 subordinates were acyclic at the end of the study, and instances of ovulation typically resulted in aggression. Goeldi's monkey sister pairs showed no status differences: in all pairs, however, both sisters exhibited a temporary cessation of ovarian cyclicity on trio formation, followed by ovulation and conception. We conclude that these marked differences in ovarian responses reflect the differences in inter-female competition for paternal caregiving resources. In common marmosets with high inter-female competition, suppression of ovulation functions to reduce aggression received by subordinate females; in Goeldi's monkey with low competition, temporary cessation of ovulation could facilitate female choice.