Reduction of Female Mating Receptivity after Injection of Male-Derived Extracts in Trigonotylus caelestialium (Heteroptera: Miridae)

The effects of male-derived extracts on female receptivity to remating were investigated in Trigonotylus caelestialium (Kirkaldy) (Heteroptera: Miridae). The aqueous extracts of male reproductive tracts were observed to reduce receptivity both at 3 h and at 1 d after injection into the abdomens of females. Next, ultrafiltration was used to divide the aqueous extracts of the male reproductive tracts into three molecular-weight (MW) fractions: 14 kDa. The filtrate containing the MW substances 14 kDa inhibited receptivity at 1 and 2 d after injection. Finally, the male reproductive tract organs were divided into the accessory glands, testes, and the remaining reproductive organs, including the seminal vesicles. Aqueous extracts of the accessory glands reduced the receptivity of females both at 3 h and 2 d after injection, whereas those of the testes decreased the receptivity of females at 3 h after injection. Together, the results indicate that more than one mechanism may be involved in the effects of male-derived substances on female receptivity in T. caelestialium. The findings suggest that low-MW male-derived substances in the accessory glands and testes cause short-term inhibition and that the high-MW substances in the accessory gland inhibit female mating at a later period.