Courtship behavior of phycitid moths. I. Comparison of Plodia interpunctella and Cadra cautella and role of male scent glands

Abstract

Courtships of the Indian meal moth, Plodia interpunctella, and the almond moth, Cadra cautella, were observed in the laboratory in petri dish arenas. The sequence of behavioral responses which alternate between male and female are released by tactile, visual, and pheromonal stimuli arising from both sexes. The courtship sequences are species specific if males approach females from the rear, but are quite similar if males approach from the front facing the females. For both species the most important feature of courtship is the female's acceptance posture (female stationary with abdomen elevated between wings), which releases male copulatory behavior and facilitates copulation.During courtship, male Indian meal moths release a sex pheromone from wing glands located at the base of each forewing. By completely amputating the female's antennae or the male's forewings including glands, it could be shown that the male pheromone induces the female to remain stationary and adopt the acceptance posture. In the absence of male pheromone, the female actively rejects the courting male and does not mate. These observations are supported by quantitative data. A male pheromone could not be demonstrated for male almond moths but it is argued that a pheromone is probably involved in the courtship of this species as well.