The Research On The Feature Of Diapause And Adaptability To Plant In Ophraella Communa Lesage

This paper studied the mechanism of audlt diapause and effects of plants on the development and reproductive of Ophraella communa LeSage which collected from Changsha of Hunan Province. The study results are as follows:(1) To understand its seasonal adaptation strategies in the new habitat, in the present study, we investigated the effects of photoperiod and temperature on female reproductive development of Changsha strain of O. communa. Our results indicated photoperiod did not affect the larva development and duration of pupa at 25℃, but female adults showed reproductive diapause obviously and the incidence of diapause is regulated by photoperiod and temperature in Changsha strain of O. conmuna. The pre-oviposition period and oviposition activity of females were not influenced by photoperiods when insects were reared from newly hatched larvae at 30℃, but females entered intensive reproductive diapause under short days at 20℃and only partial female emerge diapause under short days at 25℃. When shifts from long-day to short-day after pupation the oviposition activity of females were restrained, and shifts photoperiod after adult emergence, females delayed their pre-oviposition period and decreased the No. of eggs deposited. These results indicated both pupa and adult stage were the photoperiodic sensitive period in O. conmuna.(2) The duration of larvae and pupae, pupation rate, eclosion rate,number of eggs laid, laid rate and the female and male longevity of Ophraella communa were investigated when Ophraella communa were fed with ragweed, sunflower and xanthium. Meanwhile, the hatching rate of the second generation female were also compared.When fed with xanthium and sunflower, Ophraella communa can finish a generation, but duration of larvae, which were fed with xanthium, is significant longer than that the larvae which were fed with ragweed. Meanwhile, pupation rate, eclosion rate, hatching rate of offsprings, femal longevity and male longrvity is significant decreased when the Ophraella communa were fed with xanthium,. The females,fed with xanthium produced less amount of 1/3 eggs compared to the females fed with ragweed. These results showed that xanthium is not the suitable host plants for Ophraella communa.The female fed with sunflower produced less eggs than the female fed with the ragweed, but there is no significant different in duration of larvae, pupation rate, eclosion rate and hatching rate of offsprings between them. On the other hand, the adult longevity and eggs laid of F2 is decreased than F1. Specially laid rate of F2 is significant lower than F1. That means the population of Ophraella communa will become few and few when fed with sunflower.