title: Sex differences in the protection of host immune systems by a polyembryonic parasitoid.
abstract: Endoparasitoids have the ability to evade the cellular immune responses of a host and to create an environment suitable for survival of their progeny within a host. Generally, the host immune system is suppressed by endoparasitoids. However, polyembryonic endoparasitoids appear to invade their hosts using molecular mimicry rather than immune system suppression. It is not known how the host immune system is modified by polyembryonic endoparasitoids. Using haemocyte counts and measurement of cellular immune responses, we evaluated modification of the host immune system after separate infestations by a polyembryonic parasitoid (Copidosoma floridanum) and another parasitoid (Glyptapanteles pallipes) and by both together (multi-parasitism). We found that the polyembryonic parasitoid maintains and enhances the host immune system, whereas the other parasitoid strongly suppresses the immune system. Multi-parasitization analysis revealed that C. floridanum cancelled the immune suppression by G. pallipes and strengthened the host immunity. This enhancement was much stronger with male than with female C. floridanum.
authors.affiliation: Faculty of Agriculture, Tokyo University of Agriculture and Technology, , Fuchu, Tokyo 183-8509, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Nishikawa
authors.forename: Jin
authors.initials: J
authors.lastname: Yoshimura
authors.forename: Kikuo
authors.initials: K
authors.lastname: Iwabuchi
mesh_terms: D000818:Animals; D005260:Female; D006098:Granulocytes / Q000166:cytology; D006434:Hemocytes / Q000166:cytology / Q000378:metabolism; D006458:Hemolymph / Q000737:chemistry; D006790:Host-Parasite Interactions / Q000502:physiology; D007107:Immune System / Q000502:physiology*; D019476:Insect Proteins / Q000378:metabolism; D007915:Lepidoptera / Q000469:parasitology*; D008297:Male; D010587:Phagocytosis; D016012:Poisson Distribution; D012737:Sex Factors; D014863:Wasps / Q000276:immunology*
chemical_list: D019476:Insect Proteins
keywords: Copidosoma floridanum; Glyptapanteles pallipes; haemocyte counts; immune response; multi-parasitism