A systematic revision of the Japanese species of the genus Therion


Shimizu, S., Bennett, A.M.R., Ito, M., Maeto, K. (2019). A systematic revision of the Japanese species of the genus Therion. Insect Systematics & Evolution, [online] 50(1), 36-66. http://dx.doi.org/10.1163/1876312X-00002180

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This paper reviews the species in the parasitic wasp genus Therion from Japan. These wasps parasitize caterpillars, some of which are pests on agricultural crops and forests. A key with images is provided which allows people to be able to distinguish the four species. Two of the species were not previously known to science, so they were described as new species. This study is of importance to Canadian agriculture because one of the species of wasps is also found in Canada and many species of pests of agriculture and forests are shared between Japan and Canada. Knowledge of the parasitic wasp species of Japan could be important if invasive pests come into Canada from Japan. Japanese parasitic wasps could then be introduced to Canada to help control the invasive pests.


The Japanese species of the genus Therion Curtis, 1829 (Ichneumonidae: Anomaloninae) were revised based on examination of 447 Japanese specimens. Four species are recognized based on morphology and sequence data (mtCOI). Two of them are identified as previously known species: T. circumflexum (Linnaeus, 1758) and T. giganteum (Gravenhorst, 1829). The other two species are described as new: T. carinatum Shimizu & Bennett, sp. nov. and T. nigrigasterum Shimizu, Bennett & Ito, sp. nov. In addition, T. rufomaculatum (Uchida, 1928) stat. rev. is once again synonymized with T. circumflexum. The Japanese species of Therion are easily distinguished from each other by a newly provided key. The lasiocampid moth, Dendrolimus spectabilis (Butler, 1877), is newly recorded as a host of T. giganteum.

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