A Chance Encounter: The Case of a Western Conifer-Seed Bug Biting a Human

western conifer-seed bug

The western conifer-seed bug (Leptoglossus occidentalis), a plant-eating insect, has been documented to have bitten a human, though researchers consider the bite to have been a chance occurrence and not the result of the insect targeting the human. (Photo credit: Joseph Berger, Bugwood.org)

Bed bugs, mosquitoes, ticks—and the western conifer-seed bug? Well, if you’re making a list of insects that have been recorded having bitten a human at least once, ever, then yes. But the western conifer-seed bug is almost certainly not our next great insect menace.

In a brief report published last week in the Journal of Medical Entomology, a pair of researchers in Hungary document what they say is the first and only known case of a western conifer-seed bug (Leptoglossus occidentalis) biting a human. It occurred in late July 2016 in Budapest, and the bug was promptly caught, documented, and preserved. The person bitten was an acquaintance of one of the researchers and, in a bit of luck, had ethanol on hand in which to preserve the specimen.

The researchers consider the bite to have been essentially an accident or fluke, because, as its name implies, the western conifer-seed bug feeds on seeds and shoots from coniferous trees, using its long piercing-sucking mouthparts to extract fluid from them. It is known as a phytophagous (plant-feeding) insect, not a hematophagous (blood-feeding) one.

Why, then, report the occurrence? Sandor Hornok, Ph.D., co-author of the paper and associate professor in the Department of Parasitology and Zoology at the University of Veterinary Medicine in Budapest, says it is important to enter the potential for L. occidentalis to bite humans into the scientific record, particularly considering the species’ ongoing spread from the Americas into Europe and Asia.

The bite resulted in a painful irritation and a lesion that lasted 48 hours, according to the report. Afterward, an area of redness on the skin around the bite remained for four weeks. The researchers suggest that the western conifer-seed bug may be mistaken for a wasp or other insect, but medical professionals diagnosing insect bites should at least be aware of the possibility that the western conifer-seed bug could be a culprit.

“It would be important to collectively know all similar categories of plant-associated bugs which may bite humans, as we also know that this phenomenon is not unique for the western conifer-seed bug,” says Hornok.



  1. Western conifer seed bugs have been making their way East in North America for years, and we have them in Maine, especially in the late fall when they come inside to get out of the cold. I’ve been nipped by one.

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