The Effect Of20-Hydroxyecdysone On Diapause、Metabolites、Egg Size Of Cotesia Vestalis

Cotesia vestalis (Haliday) is one of the most important solitary larval endoparasitoid of Plutella xylostella (Linnaeus), have become an important pillar of diamondback moth prevention in many Southeast Asian countries, and it distributes widely in our country, south to Guangdong and north to Jilin. Reproduction, long-term storage, timely release of wasps is the key to effectively using the wasp to control diamondback moth, therefore diapause stage became the most favorable stage for storage. When photoperiod is13h or less, the temperature below17±wasps can be induced to entry into diapause. The diapause pre-pupal can be stored at low temperature for160d, greatly extend the storage period. Thus it is necessary to study diapause. Molting hormone is a hormone that is closely related with diapause, according to existing research results, it shows that with the extension of the light cycle, the content of20-Hydroxyecdysone(20E) in Cotesia wasps adult female, as well as the egg before and after oviposition are significantly increased, the corresponding progeny diapause incidence is significantly reduced. So we speculate that20E play an important role in passing message from mother to offspring. In view of this, by the female wasp, which have been injected with20E or have been applicated at the pupal stage, parasitized2-3instar larvae of diamondback moth, cultured under15±with a photoperiod of8L:16D until the formation of the cocoon, then we observe changes in their diapause rate. At the same time, taking into account that the hydrogen peroxide, sugar, egg size are closely related with diapause, and they may play roles in transferring maternal effects, and thus, we also study the effect of20E on content of hydrogen peroxide, sugar of adult female and the size of egg. The results are as follows:1.Compared with the control, the Cotesia wasps emergence rate is not be affected by apply application of250-2500ng20E on pupae; The longevity of Cotesia wasps is not be affected by injection10-100ng20E to the adult female.2.Compared with the control, the pupal treated with250-2500ng20E and adult female treated with10-100ng20E, the offspring diapause were not be affected.3.Compared with the control, after the injection of10-100ng20E, it does not effect the content of trehalose of adult female and size of egg after oviposition, but the size of egg before oviposition is decreased significantly, glycogen content increases significantly, total sugar content decreased significantly, and hydrogen peroxide content raised significantly at24h after injection, reduced significantly at48h post-injection.