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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,

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.

    • My dog was just bitten by one today in Northeast Ohio. He started howling and rubbing his face on the ground and even threw up a little bit. He seems fine now, but if he starts showing any other signs of something being wrong, I’ll definitely take him to the vet.

  2. I live in Wisconsin and am quite familiar with these bugs. At least, I thought I was. I was under the impression that they did not bite but a week ago at night, one was in my bedroom and landed on me while I was sleeping. At first, I thought it was a wasp given the noisy flying so before I tried to grab it, I used my cell phone to cast light on the insect. When I saw it, I grabbed it with my hand thinking it harmless. It stung me! I was so shocked!! I thought that somehow I had been mistaken and it was indeed a wasp. It wasn’t. I found the bug on the floor and confirmed it to be a conifer seed bug. Not wanting to be bitten again, I went to find something to protect my hand and when I got back, I couldn’t find it! Of course. Time went on and I didn’t think much more about it but now it’s been over a week and I woke up to a red swelled area around the sting location and itching. Scouring the internet was of no use and I started to think I was crazy until I found this. Currently, I’m using topical and oral benedryl trying to get the symptoms controlled. Hopefully, this saga is nearly at it’s end and I don’t end up having to go to the doctor for the sting because I’m sure they will tell me that I’m crazy.

  3. I have been bitten by these bugs over the years a few times since they started to appear in eastern CT; the notion that they do not bite is ludicrous. The bite action is slightly painful though not as painful as say a bee or wasp sting; I personally have had no particular reaction on my skin to the bites. But they will bite if they land on you and they feel “threatened” somehow.

  4. I have been bitten. By mistake I sat my elbow right on him. It stung like a smaller bee and left a red spoton my elbow for 4 days. Turned into a small scab. Actually was itchy for the first 2 days a bit burning. Now just a mark. We get these bugs every year. They live in my siding on my house.

  5. I live in Ohio, I pick them up all the time and I pick up shield bugs. To me they are are beautiful. Never been bitten by either. Once though a shield bug tried putting its proboscis in my finger, don’t think it meant to. Maybe you got poked with its proboscis. (It’s their tube like mouth part, how they eat)

  6. I got bite while in a field watching fireworks. I believe it was this bug – my husband and I both described it to look like a larger stink bug. It hurt – felt like someone stuck a pin in my leg, then proceeded to burn similar to a bee sting. The area then swelled and now I have a large bump there that is somewhat itchy. I had to ice it when I got home. This happened in Hillsborough, NJ.

  7. I was bitten by one in the fall of 2017 it took a long time to heal and I ended up having to get a prescription cream. I had pictures of the bite to document it Even tried to contact the men in Hungary but unfortunately no luck.

  8. I was stung by this bug a few weeks ago on the ankle. It hurt somewhat like a mild bee sting but the worst part was the afteraffects. I became nauseas and dizzy for 12 hours and fought off fainting all day. 2 weeks later and there is still a mark where it stung me but the symptoms only lasted for the 12 hours.

  9. Just bit this morning by this bug. Thought it was a stink bug except it readily flies and has those thick rear legs. I thought I was stuck by a sharp leaf on a plant I was carrying then this guy took off. they spot kept getting more painful with a burning sensation. There is a small red blister like mark where he bit and the area has become quite warm to the touch. After about 2 hours the discomfort has subsided. I did get a picture of the bug if anyone is interested. Glad to see that others have had a similiar experience. Well, not glad that they were also bit but glad that I am not the only one!

  10. Approaching winter and a spell of colder weather brought a few of these into my dorm room. I woke up and found a couple bites on me and had no idea what it was. I found one inj my room and captured it and started doing research thinking this is what bit me. A few nights go by and I now have 5 bites total. Today I found two more in my room. I put them all in the same cup with a bit of water and the biggest one killed the other two within several minutes and is still alive. I also recall siting down at my desk and feeling this sharp sting on my upper butt lower back area. It was dark in my room and I didn’t know what it was. The other bites occurred while asleep. No new bites since catching them.

  11. Hi
    I live in Durban, South Africa and this week we suffered bites in my daughter’s room. We thought it was bed bugs. But the bugs were big (and I caught one biting me) and on identifying with an app, learn its 75% confidence of deuches genus, a seed bug. I must say it does look like the picture to me. In case there is interest, I can forward a picture.

  12. In Northern Utah, we have seen these for the last two years. They are terrible! My husband and I have both been bitten by them. It hurts and itches for weeks on end.

  13. I was bitten last night in Windsor, Ontario. It didn’t burn like a wasp sting but my bitten finger is swollen today. Still feel irritating at the bite site.

  14. Bitten by one Dec. 18, 2021. Lancaster, PA. Worse than any wasp sting. On its way down, but still swollen 3 days later.

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