Breeders are less active foragers than non-breeders in wild Damaraland mole-rats

Abstract

Eusocial societies are characterized by a clear division of labour between non-breeding workers and breeding queens, and queens often do not contribute to foraging, defence and other maintenance tasks. It has been suggested that the structure and organization of social mole-rat groups resembles that of eusocial insect societies. However, the division of labour has rarely been investigated in wild mole-rats, and it is unknown whether breeders show decreased foraging activity compared with non-breeding helpers in natural groups. Here, we show that, in wild Damaraland mole-rats (Fukomys damarensis), breeders show lower activity in foraging areas than non-breeding group members. Both breeders and non-breeders displayed variation in activity across the different seasons. Our results suggest that group living allows social mole-rat breeders to reduce their investment in energetically costly behaviour, or alternatively, that the high cost of reproduction in this species forces a behavioural trade-off against foraging investment.