Nestmate-brood recognition among workers of different social status in Ectatomma tuberculatum Olivier (Formicidae, Ponerinae).

Experiments were carried out to test nestmate-brood recognition in the neotropical ant species Ectatomma tuberculatum, belonging to the primitive subfamily Ponerinae. In the same laboratory colonies, two behavioural subcastes, nurses and foragers, were given simultaneous choices between nestmate and non-nestmate brood (larvae or cocoons). Nurses and foragers dramatically differed in their response during the choice test. Qualitative differences appeared in the type of brood tending displayed by the two worker categories. In particular, licking and transport were more represented in the nurse than in the forager repertoire. Moreover, the number of acts delivered by nurses was significantly higher toward nestmate than non-nestmate brood and there was no significant difference in the amount of behavioural acts directed by foragers toward the two brood categories. The social status of the worker therefore appears to strongly influence brood discrimination.