Worker oviposition and policing behaviour in the myrmicine ant Aphaenogaster smythiesi japonica Forel

In eusocial Hymenoptera, worker reproduction is affected by various factors, especially the genetic structure of the colony. Kinship theory predicts that hymenopteran workers prefer to produce sons rather than brothers when a single, once-mated queen is in a colony, while such worker reproduction is expected to be mutually inhibited by other workers under multiple mating of the queen. To test these predictions we observed the behaviour of the myrmicine ant Aphaenogaster smythiesi japonica. Observation of the social structure of 60 queenright colonies indicated monogyny and microsatellite DNA analysis of 14 colonies showed monandry. Under laboratory conditions, workers with functional ovaries laid only trophic eggs in the presence of the queen and produced viable eggs in her absence. In an experiment in which colonies split and reunited, workers that had well-developed ovarioles with viable oocytes were frequently attacked by other workers from the queenright groups. The number of cocytes in a worker's ovarioles was positively correlated with the frequency of being attacked. The results show that a worker's production of males in this species is potentially inhibited by worker policing, contrary to the prediction that worker policing is not predominant in monogynous and monandrous societies. (C) 2003 Published by Elsevier Ltd on behalf of The Association for the Study of Animal Behaviour.