Kin-based male mating preferences in two species of halictine bee

Summary In both of the social bee species Lasioglossum (Dialictus) zephyrum and Lasioglossum (Evylaeus) malachurum (Hymenoptera: Halictidae), males are shown to be attracted to females in field experiments by a pheromone which covaries among female relatives. Females sampled from a nesting aggregation other than the one in which the tested males occur are slightly more attractive than females from the males' own aggregation, and always significantly more attractive than females whose pheromones have been extracted. Furthermore, in L. malachurum experience with a female alters the response of the males towards that female and towards her nestmates (most probably close relatives) in further encounters, but does not alter the males' responses towards females who were non-nestmates of the experienced one. These data indicate that some form of learning of female kin-identity takes place in adult males, and influences the mating system. How males may integrate kinship information into a mating strategy is discussed.