FLOWER CHOICE BY HONEY-BEES (APIS-MELLIFERA L) - SEX-PHASE OF FLOWERSAND PREFERENCES AMONG NECTAR AND POLLEN FORAGERS

Bees foraging for nectar should choose different inflorescences from t hose foraging for both pollen and nectar, if inflorescences consist of differing proportions of male and female flowers, particularly if the sex phases of the flowers differ in nectar content as well as the occ urrence of pollen. This study tested this prediction using worker hone y bees (Apis mellifera L.) foraging on inflorescences of Lavandula sro echns. Female flowers contained about twice the volume of nectar of ma le flowers. As one would predict, bees foraging for nectar only chose inflorescences with disproportionately more female flowers: time spent on the inflorescence was correlated with the number of female flowers , but not with the number of male flowers. Inflorescence size was inve rsely correlated with the number of female flowers, and could be used as a morphological cue by these bees. Also as predicted, workers forag ing for both pollen and nectar chose inflorescences with relatively gr eater numbers of both male and female flowers: time spent on these inf lorescences was correlated with the number of male flowers, but not wi th the number of females flowers. A morphological cue inversely associ ated with such inflorescences is the size of the bract display. Choice of flowers within inflorescences was also influenced predictably, but preferences appeared to be based upon corolla size rather than direct ly on sex phase.