Mesochorinae

It is certain that most of the members of this subfamily are D. hyperparasitic, and I speculate that those Mesochorinae which may eventually be proven not to be hyperparasitic will be shown to be cleptoparasitic. Some species of Mesochorinae parasitize other Ichneumonidae, but a greater number parasitize Braconidae. At least four Nearctic species of Mesochorus have been reared from Tachinidae. The hosts of Mesochorinae are internal parasites of various insects, most of the latter being phytophagous. Mesochorinae have been reared from parasites of Lepidoptera, Symphyta, Coleoptera, Miridae, and, according to Dr. C. C. Loan (personal communication, 1975), even Psocoptera. Mesochorines insert the ovipositor into the secondary host and in turn locate the early-instar larva or even the egg of a primary parasite and oviposit inside the latter. ~Dasch (1971) said that "considerable evidence seems to indicate that many species [of Mesochorinae] are primary parasites of lepidopterous and coleopterous larvae," but this statement appears to be inaccurate. For Mesochorinae to be primary parasites of these hosts, they would have to spin their own cocoons or emerge from lepidopterous pupae. I do not know of any case in which a mesochorine specimen is mounted with a lepidopterous pupa from which it emerged or is otherwise known with certainty to have emerged from a lepidopterous pupa. In substantiated cases of emergence from lepidopterous pupae, proof of primary parasitism could be made only through dissection of the host remains, because mesochorines may be able to parasitize primary parasites which oviposit into lepidopterous larvae and emerge from the pupae (such as Anomaloninae [Dasch (1971) cited a published record of a Trichionotus sp. as a host], Metopiinae Ichneumoninae, certain Campopleginae, or meteorideine Braconidae). In any case, the majority of mesochorine specimens labeled as being reared from Coleoptera or Lepidoptera have emerged from cocoons, and when these specimens are mounted together with the cocoons from which they have emerged, the cocoons prove to be those of Braconidae or other Ichneumonidae. The only possible exception that I am aware of is Plectochorus iwatensis (Uchida), a Eurasian species which apparently spins a cocoon of its own and thus appears to be a primary parasite of Grapholitha molesta (Bsk.) (cf. Haeussler, 1940). It is remotely possible that some of the species of Mesochorinae which have been reared from cocoons of sawflies could be primary parasites, but this could not be established without dissecting the contents of the cocoons and determining that they do not include the larval remains of an additional ichneumonid or an ichneutine braconid.

Mesochorinae is a worldwide subfamily of the parasitic wasp family Ichneumonidae.

Mesochorinae are koinobiont hyperparasitoids of ectoparasitic or endoparasitic Ichneumonoidea, and, less frequently, of Tachinidae (Diptera). There are 10 genera.

Mesochorinae