Effect Of Rifampicin Treatment On Fitness Of Nasonia Vitripennis(Hymenoptera:Pteromalidae)Infected With Wolbachia

Nasonia vitripennis (Hymenoptera:Pteromalidae) is widely distributed in the world and an important parasitic wasp of fly pupae. It is often used to experimental research because of its clear genetic background, large population and convenient operation etc. In2010, the genome of Nasonia vitripennis has been sequenced. This greatly speeds up the research about N. vitripennis. Now, N. vitripennis is recognized as a potential model organism.Wolbachia is an obligate intracellular symbiotic with maternal lineage. It is widely distributed in arthropods and can manipulate the reproduction and fertility of its host. It can also induce cytoplasmic incompatibility (CI), feminization, parthenogenetic induction(PI) and male killing(MK).In this article, eight kinds of concentration rifampicin (a kind of antibiotics) was used to feed N. vitripennis in order to explore the influence of different concentration rifampicin and detect the effect of removing Wolbachia. To evaluate effect of Wolbachia on reproduction of N. vitripennis, number of amount of adult emerging per pupa and sex ratio with10consecutive generation were investigated after Wolbachia was removed. Finally, we also studied whether Wolbachia will affect the life of the N. vitripennis. Results were as following:(1) The effect of different concentrations of rifampicin treatment on N. vitripennis and the efficiency of removing Wolabchia. Different concentrations rifampicin will have a significant impact on N. vitripennis. The mortality of N. vitripennis is increased with the rising of concentration of rifampicin treatmeat. Wasps mortality reached50%when1.0mg/ml rifampicin was used despite feeding time was24h; Wasps mortality reached90%when5.0mg/ml rifampicin was used when feeding time was5d, while the wasps mortality was only10.03%when0.1mg/ml rifampicin was used when feeding time was7d, much lower than the higher concentration of rifampicin. This shows that we should use the lower concentration of rifampicin when we want to remove the Wolbachia of N. vitripennis. So according to the experimental results ideal rifampicin concentration should be controlled between0.1mg/ml and0.5mg/ml.(2)Effect of rifampicin with different concentrations treatment on amount of adult emerging per pupa. Because high concentrations of rifampicin has an potential lethal threat on N. vitripennis, although after many generations, descendants still show the effect of high concentrations of rifampicin on N. vitripennis, reducing the amount of adult emerging per pupa. It reduced the amount of adult emerging per pupa on N. vitripennis between8.7%and 16.7%. Wolbachia can also have an effect on amount of adult emerging per pupa. Compared with control group, the amount of adult emerging per pupa of N. vitripennis also was reduced by4%-8%.(3) Effects of Wolbachia-infection on sex ratio of N. vitripennis. In our study, we found that Wolbachia had a significantly effect on sex ratio, while the rifampicin had a little effect on sex ratio. The sex ratio of female N. vitripennis infected Wolbachia is between80%-85%, while the sex ratio of female N. vitripennis uninfected Wolbachia is65%-70%. That is to say, Wolbachia can increase the female proportion of the offspring.(4) Effects of Wolbachia-infection on longevity of female N. vitripennis. Experiments found that there is no obvious influence between treated group and control group on longevity of female wasps. So we can draw a conclusion that Wolbachia did not have a significant effect on the longevity of female N. vitripennis.