Effect of age and multiple mating on the mating behavior of Culicoides nubeculosus (Diptera: Ceratopogonidae)

The mating behavior of the biting midge Culicoides nubeculosus (Meigen) may be divided into a number of stages, including resistance behavior of the female before copulation. A previous study indicated that resistance behavior is a method through which the female assesses the fitness of the male, allowing some degree of mate choice. Our study used behavioral and electrophysiological techniques to investigate whether insect age and the reproductive status of the females influenced mating behavior. Virgin females became increasingly receptive to mating attempts as they aged, with reduced resistive behavior and a reduction in the time required for genital union. With increasing male age, the duration of copulation increased, possibly related to the time required for the transfer of sperm. Previously mated females were very resistant to further attempts to mate by males. Secondary matings were achieved only through the persistent efforts of males, although when successful, there were no differences in the duration of the mating process from matings with virgin females. Virgin female C. nubeculosus release a volatile sex pheromone which is detected by the males' antennae. Electrophysiological recordings from male antennae indicated that mated females have a continued but reduced output of this pheromone, which may allow males to distinguish virgin from mated females. The findings of the study are discussed in relation to possible methods of mate choice in this species.