Listrognathus 

Taxonomy

Listrognathus albomaculatus is a parasitic wasp belonging to the family Ichneumonidae and the subfamily Cryptinae. The etymology of Listrognathus albomaculatus derives from the Greek "listron," meaning "a scraper" or "a plane," and "gnathos," meaning "jaw," for the genus, and the Latin "albomaculatus," signifying "white-spotted," likely describing the white markings on the body. The geographic range of the wasp L. albomaculatus spans across North America, particularly in the eastern United States and parts of Canada. 

Description

Listrognathus albomaculatus is a small Ichneumonid wasp with an average size of 4 to 5mm. The back ridge of the wasp's head has noticeable teeth before it meets another ridge near the mouth. The wasp's body is black, with white bands clearly visible at the end of each section. The distinguishing features of this genus include a characteristic frontal horn and dense punctuation on the abdomen. The head tapers diagonally, often with a prominent forehead horn or a subtle hint of one. Eyes are typically straight, and the lower face is convex with a long space between the eye and mouth. The antennae, longer in females, taper gradually in males. The thorax is stout, with swollen upper edges and distinct "notauli" grooves. The scutellum is smooth and shiny, with few punctures, while the propodeum usually features two ridges. Wing veins may be broken, and the legs are thin. The abdomen, spindle-shaped and narrower in males, has rough punctuation and a bent first segment, often with a flange-like ridge. 

Nest Structure

Like most Ichneumonids, Listrognathus albomaculatus do not build their own nests and instead parasitize nests that are already created by other insects. L. albomaculatus is known to parasitize other insects in the order Diptera (flies) and Hymenoptera (ants, bees, and wasps). 

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

BugGuide. (2024). Species Listrognathus albomaculatus - Hodges#2392. Retrieved May 30, 2024, from BugGuide website: https://bugguide.net/node/view/919685

Cushma, R. A. 1929. A revision of the North American Ichneumon-flies of the genus Mesostenus and related genera. Proc. U.S. Natl. Mus.

Discover Life. 2024. "Ichneumonidae." In Proceedings of the Ecological Society of America, vol. 6. Accessed May 30, 2024. https://www.discoverlife.org/proceedings/0000/6/html/Ichneumonidae.html 

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