Interspecific competition between two parasitoids of Helicoverpa zea: Eucelatoria bryani and E. rubentis

Abstract

Multiple parasitism of Helicoverpa zea (Lepidoptera: Noctuidae) had differential effects on the gregarious endoparasitoids Eucelatoria bryani and E. rubentis (Diptera: Tachinidae). Both species were able to survive in multiparasitized hosts. However while the survival of E. bryani was not affected by the presence of E. rubentis, E. rubentis survival was reduced when competing with 24-h older E. bryani. The presence of E. rubentis did not result in a decrease in the size of E. bryani except when E. rubentis was 24-h older than E. bryani. The presence of E. bryani tended to result in smaller E. rubentis. The presence of similarly aged heterospecific competitors often resulted in prolonged development time for both species. Naive females did not alter oviposition between unparasitized and heterospecifically parasitized fifth-instar larvae of H. zea, either by ovipositing less frequently in parasitized hosts than unparasitized ones, or by reducing clutch size in parasitized hosts. These results indicate that in H. zea, E. bryani is a superior competitor compared with E. rubentis. These factors should be considered in evaluating the potential of E. bryani and E. rubentis as biological control agents of H. zea.

Population responses of hymenopteran parasitoids to the emerald ash borer (Coleoptera: Buprestidae) in recently invaded areas in north central United States

“…In addition, there are many examples where a single insect host is attacked by a range of parasitoid species (Hawkins 1994;Memmott et al 1994;Parry 1995). However, interspecific competition among such contemporaneously acting species is likely to affect their co-existence and may affect the establishment of the newly introduced biological control agents (e.g., Reitz 1996;Bogran et al 2002;Hackett-Jones et al 2009). How indigenous parasitoids such as Atanycolus spp.…”

Interspecific Competition among Insect Parasitoids: Field Experiments with Whiteflies as Hosts in Cotton

“…Research on competitive interactions among parasitoids has been characterized by laboratory studies in which hosts are presented to female parasitoids in various sequences and combinations (e.g., Shimada 1985, Krause et al 1990, van Alebeek et al 1993, Patil et al 1994, Baur and Yeargan 1995, Kaneko 1995, Pijls et al 1995, Bokonon-Ganta et al 1996, Reitz 1996, Williams 1996, Bautista and Harris 1997, Gauthier et al 1999, Shimada 1999. Whenever niche differences among species have been detected, these are usually attributed to interspecific interactions occurring among the tested parasitoids.…”

Multiple symbiotes in larval black flies (Diptera: Simuliidae): Associations of trichomycete fungi with ichthyosporeans, mermithid nematodes, and microsporidia

“…When two species of hymenopteran or dipteran parasitoids attack the same developmental stage in a single host, one typically eliminates the other, with the Wrst colonizer often winning (Reitz, 1996;Weir and Sagarzazu, 1998). Trichomycetes are shed from the larval gut at each molt (Lichtwardt et al, 2001); therefore, they can recolonize a host multiple times during host development and at various stages of microsporidian and mermithid pathology.…”

“…Little is known, however, about the interactions of two or more of these symbiotic taxa in the same host, and most examples have involved symbiotes not typically associated with the host but applied as biological control agents Kaya, 1990, 1991). This dearth of information contrasts with the wealth of data available for interactions among multiple parasitoid species, typically Hymenoptera or Diptera, within single host animals (e.g., Reitz, 1996;Weir and Sagarzazu, 1998).…”