Female influences on pair formation, reproduction and male stress responses in a monogamous cavy (Galea monasteriensis)

We examined the possible existence of, and female contributions to, pair bonds, as well as the relation of social preference to mating selectivity, in a recently identified wild guinea pig, the Muenster yellow-toothed cavy (Galea monasteriensis). In Experiment 1, females housed for ∼ 20 days in an apparatus in which they could choose to approach and interact with unfamiliar males typically exhibited a robust preference for one of two available males. DNA fingerprinting revealed a strong association between female choice and paternity. Experiment 2 examined the influence of the removal and return of the female on male plasma cortisol levels and behavior in established breeding pairs. A 2-h period of separation in the home enclosure elevated male cortisol levels. Return of the female to the home enclosure reduced male cortisol levels 2 h later, whereas continued separation did not. Reunion in either the home or novel enclosure increased socio-positive and courtship/sexual behavior, as well as time spent in proximity of the partner. Together, these results provide evidence for a substantial female influence on pair bond formation and maintenance in G. monasteriensis and further support for the existence of social and sexual monogamy in this species.