Reproductive Refractoriness in the Western Tarnished Plant Bug (Hemiptera: Miridae)

Abstract

Adult Lygus hesperus Knight (Hemiptera: Miridae), major crop pests of the south-western United States, can mate repeatedly during their lives, potentially enhancing the lifetime fitness of both sexes. However, the periodicity of mating and its regulation in this species is poorly understood. In this study the postmating refractory period for both sexes is described. Males were found to have a median delay of 24 h, which seems to be the minimum time needed to refill the accessory glands and produce another viably sized spermatophore. The median refractory period in mated females was 5 d, but sometimes lasted longer than 2 wk. The loss of sexual receptivity in mated females, at least for the first 24 h, seems to be induced by males; spermatophore homogenates injected directly into the abdomen of virgin females reduced their sexual receptivity. The total duration of female refractoriness may be dictated by the starting size of a spermatophore and the rate at which it degrades.