ANALYSIS OF THE AGGRESSION BETWEEN SLAVE AND SLAVE-MAKING (FACULTATIVE AND OBLIGATORY) ANT SPECIES (HYMENOPTERA-FORMICIDAE)

Using the slave Formica cunicularia as opponent, the aggressive behaviour of the slave-making ant species Formica sanguinea and Polyergus rufescens was analysed and quantified by a laboratory pair test. The two species showed different fighting techniques, The facultative slave-maker F. sanguinea engaged in prolonged combats with the opponent and used the mandibles to kill it. By contrast, the obligatory slave-making species P. rufescens at first reacted only to the attack of the slave and probably used pheromones to stop the aggression of F. cunicularia. Afterwards, if the attacks were repeated, it actively killed the slave with its mandibles. These data show the different degree of specialization reached by these two slave-makers in the evolutionary context of social parasitism.