LATITUDINAL VARIATION IN PROTANDRY AND PROTOGYNY IN POLISTINE WASPS

SUMMARY Polistes wasps (Hymenoptera Vespidae) are protogynous in the south (30°N) and protandrous in the north (42°N) of America. Sexual selection is unlikely to account for protandry because females do not mate soon after emergence, and sometimes mate multiply. North-south differences in both emergence order and relatedness of workers to brood fit the hypothesis that protandry is the result of worker conflict with the queen over the sex ratio. Protandry allows the queen to determine the sex ratio. Protogyny could be the result of greater male than female mortality prior to mating. It could also be the result of a variable and unpredictable number of days for brood production, if females can become either workers or reproductives until late in their development. In this case protogyny would allow the decision to produce reproductives rather than workers to be delayed for a few more weeks. Texas populations of P. metricus Say, P. bellicosus Cresson, P. dorsalis (Fabr.) and P. exclamam Vierek all produce ma...