Ephialtes decumbens

Taxonomy

Ephialtes decumbens belongs to the family Ichneumonidae within the subfamily Pimplinae. E. decumbens is primarily found in North America, with its range extending across various regions of the United States and Canada. 

Description

Ephialtes decumbens looks like many other Ephialtes species and it can sometimes be hard to identify specimens to species. They are around 5 to 10mm long. The mandibles are long, with the lower tooth approximately twice the length of the upper one. The face is broad and wider than it is tall, measured from the base of the antennae to the clypeal suture. The tip of the ovipositor has lower valves that extend to partially cover the upper valve, and this feature is clearly visible when viewed from above. The clypeus of this species may be whitish, and the front wings usually have very long hairs restricted to the leading edge. Their bodies are black and slender while their legs and are orange-red or yellow. 

Nest Structure

Most Ichneumonids are parasitoids whose larvae feed and develop on a single host, although some species' larvae are mobile and will feed on more than one host. Hosts include a wide range of insects in the orders Hymenoptera, Lepidoptera, Diptera, Coleoptera, Neuroptera, and Mecoptera, and spiders and spider egg sacs. Most Ichneumonids are solitary. We only had one nest that was parasitized by Ephialtes decumbens in the Bee Atlas project. The nest host was a Trypoxylon wasp, a genus of wasps that prey on spiders.

Hole Sizes

No information at this time.

Voltinism

This species appears to be univoltine throughout its range, completing one generation per year in Minnesota. 

Activity Period

No information at this time.

References

Triplehorn, C.A and N.F. Johnson. 2005. Borror and DeLong's introduction to the study of insects, 7th ed. Thomson, Brooks/Cole, Australia. 

BugGuide. 2024. "Species Ephialtes decumbens - BugGuide.Net." Accessed May 17, 2024. https://bugguide.net/node/view/1996684

Discover Life. 2024. "Ichneumonidae." In Proceedings of the Ecological Society of America, vol. 6. Accessed May 17, 2024. https://www.discoverlife.org/proceedings/0000/6/html/Ichneumonidae.html

Fitton, M. G., Shaw, M. R., & Gauld, I. D. 1988. Pimpline ichneumon-flies. Hymenoptera, Ichneumonidae (Pimplinae). 7(1).

Thank you to John Luhman for identifying all of our Ichneumonid specimens.