The police are not the army: context-dependent aggressiveness in a clonal ant.

Animals often exhibit particular 'personalities', i.e. their behaviour is correlated across different situations. Recent studies suggest that this limitation of behavioural plasticity may be adaptive, since continuous adjustment of one's behaviour may be time-consuming and costly. In social insects, particularly aggressive workers might efficiently take over fighting in the contexts of both nest defence and 'policing', i.e. the regulation of kin conflict in the society. Here, we examine whether workers who engage in aggressive policing in the ant Platythyrea punctata play a prominent role also in nest defence against intruders. The participation of individuals in policing and nest defence was highly skewed and a minority of workers exhibited most of the aggression. Workers who attacked reproductives after experimental colony fusion were less active during nest defence and vice versa. This suggests that workers show situation-dependent behavioural plasticity rather than consistently aggressive personalities.