Social impact of mara pair disruption on the formation of new bonds and reproduction in a multiple mate choice context

Abstract

Maras, Dolichotis patagonum, combine social monogamy and plural breeding, an unusual mating system for mammals. We tested how maras adapt to the forced separation of pair-bonded partners and how the potential new mates perform over the breeding season and during the process of forming new pairs. Fourteen established pairs from a captive population were randomly assigned to a control (C-group; N = 7) or an experimental (E-group; N = 7) condition. The experiment consisted of replacing seven paired males with seven socially unfamiliar males (new potential mates). Individual behaviour and social interactions were recorded over a 6-month period (spring–summer; i.e. 14 sessions) from 0800 to 1800 hours, totalling 11 hourly sampling points per session. We measured pair behaviours and degree of general behavioural synchrony over sessions 1–7 (early) and over sessions 8–14 (late). We also measured how social disruption affected the social networking of individuals forming new pair bonds as compared to individuals with established mates. We furthermore assessed the level of activity of females exposed to mate switching and the production of offspring over the breeding season. In the E-group, maras showed a reduction in pair behaviours and synchronization of activities. There were also multiple interactions among females with several males, revealing initial mate choice activity during the early time period. The period of mate choice was characterized by instability in social networking and changes in the strength of a pair's fidelity. Although the E-group included five newly established pairs, offspring production was similar to that of the C-group. Our findings show that after presumably stressful experimental social disruption, most maras re-paired in captivity, although with some delay in offspring production, suggesting that this species has the plasticity to cope with male partner loss under semicontrolled environmental conditions. However, the strength of monogamous bonds was affected by this social disruption.