摘要With proteomic analysis,we identified 379 egg surface proteins from an en-doparasitoid,Cotesia chilonis.Proteins containing conserved enzymatic domains con-stitute a large proportion of egg surface components.Some proteins,such as superoxi-dase dismutase,homolog of C.rubecula 32-kDa protein,and immunoevasive protein-2A,are classical parasitism factors that have known functions in host immunity regulation.Melanization assays revealed that a novel egg surface protein,C.chilonis egg surface ser-pin domain-containing protein had the same function as a C.chilonis venom serpin,as both suppressed host melanization in a dose-dependent manner.C.chilonis egg surface serpin domain-containing protein is mainly transcribed in C.chilonis oocytes with fol-licular cells,and it is located on both the anterior and posterior sides of the mature egg surface.Additionally,we used LC-MS/MS to identify 586 binding proteins sourced from C.suppressalis plasma located on the eggshell surface of C.chilonis,which included some immunity-related proteins.These results not only indicate that C.chilonis uses its egg sur-face proteins to reduce the immune response of its host but also imply that endoparasitoid egg surface proteins might be a new parasitism factor involved in host immune regulation.