Factors Influencing the Courtship Behaviour of Yponomeuta Vigintipunctatus (Retz.) (Lepidoptera: Yponomeutidae)

Abstract

Virgin female Yponomeuta vigintipunctatus were observed in the laboratory, to study the effects of photoperiod (16:8 hrs light-dark-cycles) and age (in days after emergence) on the calling behaviour. When calling, the female bends the abdomen ventrally, so that the pheromone glands are exposed to the air. It occurs in the dark period (1.5 lux) and achieves a maximum after 4 hours of darkness. The number of females calling varies with their age; there is a peak of activity between day 10 and 15. The perception of female sex pheromone by the male results in a mating dance similar to that of other Lepidoptera. This male activity coincides with the period of female calling. Male responsiveness is optimal between the ages of 5 and 15 days. Experiments with different testing conditions lead to a suggestion for a simple bio-assay.