A role for pheromones in mate choice in a lekking sandfly

There is increasing evidence to suggest that pheromone-mediated communication may play an important role in mate choice in many insects. We investigated the possible role of pheromones in mate choice in the lekking sandfly, Lutzomyia longipalpis, and explored whether males or females display any behavioural traits that predict patterns of male mating success. Pairs of virgin males were introduced into a small mating chamber and allowed to interact for approximately 10 min prior to the introduction of a single virgin female. The trial continued until the female copulated with one of the males. We recorded trials on video for later analysis. After a successful copulation, we determined the quantity of pheromone remaining in the glands of both males and measured the size of the pheromone glands and tergites. We corrected behaviours and measurements for body size (tergite width). Mated males had significantly more pheromone present in their glands after a trial than unmated males. Males differed in how much time they invested in wing fanning. Members of each pair of males spent similar amounts of time wing fanning but mated males and males with more residual pheromone spent more time wing fanning than their counterparts throughout the trial. The time spent wing fanning and the amount of residual pheromone were not correlated, however. A male's ability to win fights did not relate to his reproductive success. Finally, a female was equally likely to wing-fan directly at, or walk away from, either male in a given pair. The possible relationships between the amount of pheromone released and the residual pheromones left in the glands, and the level of male wing fanning and pheromone productivity, are discussed. Copyright 1998 The Association for the Study of Animal Behaviour.