Effect Of Wolbachia On Trichogramma Cacoeciae Reproductive Behavior And Its Horizontal Transfer

Wolbachia is a maternally inherited bacteria that infects the reproductive tissue of a wide range of insect species, as well as isopods, mites, and nematodes. This group of alpha-proteobacterium is responsible for various modifications in host reproduction. These phenotypes include the feminization of genetic males, the induction of parthogenetic development, and most commonly the expression of cytoplasmic incompatibility. Trichogramma wasp, which can parasite eggs of many species of Lepidoptera, is the most widely used egg parasitoid wasp in world bio-control. And it is by inducing thelytokous parthenogenesis through symbiont Wolbachia that is expected to be an effective way to improve bio-control efficiency of Trichogramma wasps. Based on molecular detection of Wolbachia wsp gene and observation of its host Trichogramma cacoeciae reproductive biology for every generation, effect of wasp symbionts Wolbachia on the thelytokous parthenogenesis of T. cacoeciae has been studied under the condition of 30℃ for 10 generations. After continuous heat treatment, behavior of T. cacoeciae thelytokous parthenogenesis was altered and PCR product of Wolbachia wsp gene turned to be negative after 4 generations. It shows that there is some relationship between T. cacoeciae thelytokous parthenogenesis and its symbionts Wolbachia. Horizontal transfer of Wolbachia by microinjection from T. cacoeciae to Tdendrolitni has also been studied. According to the results of three generations of microinjection, the average of survival rate is only to 2.1%. And wsp gene that whether in T.dendrolimi or not after injection has been detected and the PCR products are all negative. Besides, the other part of this research suggested that there is another way of Wolbachia horizontal transfer that uninfected parasitoid wasp can be infected by Wolbachia harboured in its infected host. The conclusion drawn in this research will make a preparation of experiment technique and academic evidence for further study and application of Wolbachia in Trichogramma in the field of bio-control.