title: WASP-ASSOCIATED FACTORS ACT IN INTERSPECIES COMPETITION DURING MULTIPARASITISM.
abstract: Coexistence or displacement of parasitoids in hosts during intrinsic competitive interactions between different parasitoid species (multiparasitism) may depend on their life history traits and behavior. Intense competition for possession of hosts may lead to the elimination of the inferior competitor through physical attack and/or physiological suppression. However, the mechanisms of physiological suppression during multiparasitism remain unclear. Previous work has shown that first instar larvae of the solitary endoparasitoid Meteorus pulchricornis possess well-developed mandibles that are used to kill competitors. Two gregarious endoparasitoids, Cotesia kariyai and C. rufricus, share host resources especially when the time gap of oviposition is short. Here, we investigated the physiological influence of wasp-regulatory factors of the three endoparasitoids, M. pulchricornis, C. kariyai, and C. ruficrus, in their common host Mythimna separata. We found that MpVLP alone (or with venom) deleteriously affected the development of the two gregarious species. Similarly, CkPDV plus venom had toxic effect on M. pulchricornis eggs and immature larvae, although they were not harmful to immature stages of C. ruficrus. Cotesia kariyai and C. ruficrus were able to coexist mainly through the expression of regulatory factors and both could successfully emerge from a multiparasitized host. The injection of CkPDV plus venom after oviposition in L5 host larvae facilitated C. ruficrus development and increased the rate of successful parasitism from 9% to 62%. This suggests that the two gregarious parasitoid wasps exhibit strong phylogenetic affinity, favoring their coexistence and success in multiparasitized hosts.
authors.affiliation: Laboratory of Applied Entomology, Graduate School of Bio-Agricultural Sciences, Nagoya University, Chikusa, Nagoya, Japan.
authors.forename: Peter M
authors.initials: PM
authors.lastname: Magdaraog
authors.affiliation: Laboratory of Applied Entomology, Graduate School of Bio-Agricultural Sciences, Nagoya University, Chikusa, Nagoya, Japan.
authors.forename: Toshiharu
authors.initials: T
authors.lastname: Tanaka
authors.affiliation: Department of Terrestrial Ecology, Netherlands Institute of Ecology, Wageningen, The Netherlands and Amsterdam Free University.
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Harvey
mesh_terms: D000818:Animals; D020387:Food Chain; D006790:Host-Parasite Interactions / Q000502:physiology*; D007814:Larva / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000469:parasitology; D009036:Moths / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000469:parasitology*; D010063:Ovum / Q000254:growth & development / Q000378:metabolism / Q000469:parasitology; D018071:Polydnaviridae / Q000502:physiology; D011679:Pupa / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000469:parasitology; D014862:Wasp Venoms / Q000494:pharmacology; D014863:Wasps / Q000737:chemistry / Q000254:growth & development / Q000502:physiology* / Q000821:virology
chemical_list: D014862:Wasp Venoms
keywords: Cotesia kariyai; Cotesia ruficrus; Meteorus pulchricornis; intrinsic competition; polydnavirus; resource sharing; scramble competition; venom; virus-like particles