Strongly bonded individuals prefer to forage together in cooperatively breeding dwarf mongoose groups

Abstract

In many social species, group members form strong social bonds. Such strong bonds are well-known to generate long-term fitness benefits, but they are also expected to influence short-term behavioural decisions. Here, we use field observations and an experimental manipulation to investigate whether variation in social-bond strength (as determined from grooming interactions) influences nearest-neighbour choices while foraging in wild dwarf mongooses (Helogale parvula). Preferred grooming partnerships (PGPs), representing particularly strong bonds, were found predominately between male–female dyads but among a range of dominance-status dyads. When searching for food, dwarf mongooses with PGPs were more likely than expected by chance to forage close to a preferred grooming partner. Foraging near a strongly bonded groupmate might reduce the predation risk or increase foraging opportunities and the transfer of social information. In addition, there could be stress-reducing benefits, although our field experiment provided no evidence that nearest-neighbour preferences for strongly bonded groupmates were additionally favoured, or indeed disrupted, in the aftermath of a short-term stressful event. Investigating the potential influence of strong social bonds on short-term behavioural decisions with potential fitness consequences is important for our understanding of social interactions and cooperation. Enduring, close social bonds between individuals provide considerable long-term health and fitness benefits, but are also expected to influence short-term behavioural decisions. We investigated whether social-bond strength (as determined from grooming interactions) influenced foraging decisions in cooperatively breeding dwarf mongoose groups. We found particularly strong social bonds in the form of preferred grooming partnerships in a subset of male–female dyads. Dwarf mongoose foraging decisions were affected by the strength of their social relationships with groupmates: individuals with preferred grooming partners preferred to have these individuals as their nearest neighbours when searching for food. We used a field-based experimental manipulation to investigate whether stressful events impact nearest-neighbour choices, but found no evidence that preferences to forage near strongly bonded groupmates were disrupted or more additionally favoured in the aftermath of a stressful event. Our current work extends understanding of how social bonds can potentially influence within-group behaviour.