Riptortus pedestris (Heteroptera: Alydidae), an important crop pest, is capable of entering reproductive adult diapause under short-day photoperiods. Though the physiological aspects of adult diapause have been well studied in this species, little is known about its morphological development. In the present study, the adult females are discriminated as prediapause and prereproductive based on the absence and presence of mature oocytes in ovarioles, respectively. We also measured the morphological development of vitellarium and lateral oviduct in females, and the accessory gland, ejaculatory duct, and testes in males of both prereproductive and prediapause adults. Our results revealed that there is a clear significant difference in the reproductive development of prediapause and prereproductive insects. Moreover, the internal morphology of reproductive organs was suppressed in prediapausebugs compared to prereproductive bugs, and the insects developedthe reproductive parts as newly emerged adults. The above findings provide basic knowledge on the characterization of diapause and reproductive R. pedestris adults, which would be applicable to molecular investigations.
Keywords: Riptortus pedestris; internal reproductive organ; morphology; photoperiod; reproductive diapause.