Intracolony aggression in the eusocial naked mole-rat, Heterocephalus glaber

In colonies of the eusocial naked mole-rat, breeding is monopolized by one dominant female (the 'queen') and one to three males. Aggression in the for m of shoving (prolonged pushes involving nose to nose contact) is frequentl y observed in captive colonies and is principally initiated by breeders. It has been suggested that shoving by queens functions primarily to suppress reproduction in subordinates (threat reduction hypothesis) or to incite wor k activity in nonbreeding 'helpers' (work conflict hypothesis). We tested p redictions of both hypotheses by examining shoving in five captive colonies before and after removing breeders. Shoving was strongly associated with r eproductive status. The vast majority of shoves were carried out by the que en, and to a lesser extent breeding males, and the onset of reproductive ac tivity coincided with the onset, or greatly increased rates, of shoving. No evidence for the work conflict hypothesis was found. Queens shoved high-ra nking and large colony members most, a finding that does not allow discrimi nation between hypotheses. Those males that posed the greatest threat to th e queen's reproductive dominance, namely future breeding males, were shoved most, providing some support for the threat reduction hypothesis. However, evidence that queens targeted those females that posed the greatest threat , females that were to succeed them, was equivocal. Queen shoving may have several functions, depending on social context, in inhibiting reproduction in subordinates of both sexes, maintaining social order, and in inciting wo rk-related behaviours in colony members, all of which ultimately increase t he reproductive success of queens. (C) 2001 The Association for the Study o f Animal Behaviour.