Role of Web, Tactile Stimuli, and Female Sex Pheromone in Attraction of Male Twospotted Spider Mites1 to Quiescent Female Deutonymphs2

Abstract

Behavior of adult male Tetranychus urticae Koch attending quiescent female deutonymphs was analyzed by time-lapse movie photography. Males laid down a web mat across the female. Male movement was found to be largely confined within 2 body-lengths from the female. This distance served as the criterion for male response to a female sex pheromone in subsequent investigations. The role of tactile stimuli, female sex pheromone, and female deutonymph web in male attraction to quiescent female deutonymphs was investigated. Male attraction to clumps of moistened polyvinylpyrrolidone powder and to quiescent female deutonymphs alone was initially similar. However, male interest was only maintained throughout the 100 min test period when attending quiescent females. Tactile stimuli were therefore important in some initial male contact with females. The female sex pheromone then acted as an arrestant, holding the males usually within 2 body-lengths of the female. The presence of web, produced by female deutonymphs prior to quiescence, greatly increased male attraction to quiescent females.