No evidence for the work-conflict hypothesis in the eusocial naked mole-rat (Heterocephalus glaber )

Abstract

The work-conflict hypothesis (Reeve 1992) postulates that in eusocial naked mole-rat (Heterocephalus glaber) colonies there is potential conflict between the breeding female and her non-breeding colony mates over how much aid they provide in support of her reproduction. Non-breeders may withhold aid either because they are hopeful reproductives and/or because they have less to gain in terms of inclusive fitness. Breeding females should, therefore, preferentially direct aggression in the form of shoving (prolonged pushes usually involving nose-to-nose contact) towards large (hopeful reproductives) and less related non-breeders to incite them to provide aid. This study tested the following predictions of the work-conflict hypotheses. (1) There is kin bias in the shove rate of breeding females and work rates of non-breeders; (2) Shoving activates work in non-breeders. We found no evidence to suggest that the breeding female shove rate and the amount of colony maintenance activities performed by non-breeders is influenced by relatedness. Body size was a better predictor of work rate and shove rate; large animals were shoved more and worked less. Furthermore, shoving did not affect the work rate of non-breeders and rarely incited activity in inactive mole-rats. Individual mole-rats were also more likely to be shoved when already active than when resting in the nest. These results suggest that shoving by the breeding female may have functions other than the incitement of activity, such as the reproductive suppression of non-breeders.