Behavioural, demographic and fitness consequences of social instability in cooperatively breeding dwarf mongoose groups

Social instability frequently arises in group-living species, but the potential costs have rarely been investigated in free-living cooperative breeders, especially across different timeframes. Using natural observations, body-mass measurements and life-history data from dwarf mongooses (Helogale parvula), we determined the short- and longer-term consequences of a change in one of the dominant breeding pair. We found that a new breeder led to alterations in both collective and individual behaviour (i.e., increases in communal scent-marking, engagement in intergroup interactions, sentinel activity and within-group grooming), as well as reduced body-mass gain, further demographic changes and decreased reproductive success (i.e., fewer pups surviving to adulthood). The effects were particularly apparent when it was the female breeder who changed; new female breeders were younger than more experienced counterparts. Our findings support the idea that stability and cooperation are strongly lin..., ,