Short-range precopulatory behavior of males of Pectinophora gossypiella (Lepidoptera:Gelechiidae)

Abstract

The short-range precopulatory behavior of males of Pectinophora gossypiella was examined by direct observation and sequential photography. A pheromone-stimulated male takes flight and moves upwind toward a pheromone-releasing female. He usually lands several centimeters from her and then walks toward her while fluttering his wings and extending his hairpencils. The female typically withdraws her pheromone gland when the male first contacts her. The male makes a copulatory attempt and, if coupling occurs, he moves to an “end-to-end” position. Males oriented toward a synthetic pheromone source even in the absence of visual stimuli from a female, and their forward locomotion was usually arrested when they arrived at the source. Copulatory attempts were then sometimes directed toward the source. In the presence of pheromone, three-dimensional female models were much more effective than the pheromone source alone in eliciting copulatory attempts. Downwind models showed decreasing abilities to elicit male precopulatory responses with increasing distances from the source. However, increasing the amount of pheromone at the source resulted in an increase in the percentage of responses occurring at the furthest downwind models. The various components of precopulatory behavior observed for P. gossypiella are compared and contrasted with the published records of similar behaviors in other nocturnal moth species.