Biological Characteristics of Leptopilina myrica and the Effects of Its Parasitism on Host Immunity
The endoparasitoid wasp Leptopilina myrica is a newly discovered larval-pupal parasitoid of Drosophila,which was recently collected in Zhejiang Province of China.Till now,few studies have been reported on this species.In this study,we investigated the biological characteristics of L.myrica and its impact on host immune response using morphological analysis,hematological analysis and quantitative real-time PCR.The results showed that L.myrica completes its egg,larval,and pupal stages within the host body.Under the laboratory conditions,L.myrica could efficiently parasitize various Drosophila species including Drosophila suzukii.The parasitism rate and emergence rate were much higher on D.melanogaster,which was 87.3%and 70.6%,respectively.L.myrica-parasitization could induce a strong immune response in D.melanogaster:the numbers of hemocytes and differentiated lamellocytes were significantly increased in the hosts,leading to the encapsulation reaction.Moreover,the transcriptional levels of some critic immune genes in Imd,Toll and PO pathways were significantly upregulated post L.myrica-parasitization.Interestingly,L.myrica was found to evade the D.melanogaster immune response by adhering its eggs on host tissues such as intestine,thus ensured successful parasitization.The results have revealed the mechanisms of how parasitoid wasps defend themselves for survival and provided important knowledge for pest biological control.