Individual and demographic consequences of mass eviction in cooperative banded mongooses
© 2017 Published by Elsevier Ltd on behalf of The Association for the Study of Animal Behaviour.
Reason for embargo
Under embargo until 13/11/2018 in compliance with publisher policy.
In animal societies, conflict within groups can result in eviction, where individuals are often permanently expelled from their group. To understand the evolution of eviction and its role in the resolution of within-group conflict requires information on the demographic consequences of eviction for individuals and groups. However, such information is usually difficult to obtain because of the difficulty in tracking and monitoring individuals after they are evicted from their natal groups. Here we used a 15-year data set on life history and demography to investigate the consequences of eviction in a tractable cooperatively breeding mammal, the banded mongoose, Mungos mungo. In this species, groups of individuals are periodically evicted en masse and eviction is a primary mechanism by which new groups form in the study population. Following eviction, we found sex differences in dispersal distance: some females established new groups on the study peninsula but males always dispersed away from the study peninsula. Evicted females suffered reduced reproductive success in the year after eviction. For the evicting group, eviction was associated with increased per capita reproductive success for females, suggesting that eviction is successful in reducing reproductive competition. However, eviction was also associated with increased intergroup conflict for the evicting group. Our results suggest that withingroup conflict resolution strategies affect group productivity, group interactions and the structure of the population, and hence have fitness impacts that reach beyond the individual evictors and evictees involved in eviction.
Funding was provided by a Natural Environment Research Council grant no. NE/J010278/1 to M.A.C. and A.J.Y., and a European Research Council grant no. 309249 to M.A.C.
This is the author accepted manuscript. The final version is available from Elsevier Masson via the DOI in this record.