Blister beetles

Asked June 6, 2018, 6:30 PM EDT

Are these blister beetle larvae? Found in a bale of alphalpha/oat hay. Thanks, Sharon Batson

Lane County Oregon

8 Responses

Thank you for sending the images of what you suspect to be blister beetles.

For several reasons, I’ve requested an entomologist’s assistance. While we wait for a response, and if you still have the insects, please send me several additional well-focused images.

If you prefer not to wait for the entomologist’s response, you could take the insects to the Lane County Extension Service Office where the Master Gardeners can help you. The office is at 996 Jefferson Street, Eugene, OR 97402. Hours Monday through Thursday 10 am to 1 pm, and 2 to 5 pm.

Here is another image for my question: Are these blister beetle larvae?: Thanks, Sharon Batson

Oops! Here is more. Blister beetle? Thanks, Sharon B.

I'm sorry for the delayed identification. I requested assistance because I am not an entomologist. Because I have not received a response, I suspect the office is closed but I don't know for how long.

If you can take samples to the Lane County Extension Service office Monday, they may have someone who can ID them right away.
If no one is available, the samples can be submitted to OSU for a free identification.

I''m continuing to research this for you and am frustrated by the lack of images of an insect which can kill livestock if ingested in large enough numbers.

I located one small sketch in an old entomology book with a resemblance to your images which strongly suggests the insects you have are blister beetles.

I wonder if your veterinarian might have some insights. Or perhaps a local farm store or knowledgeable neighbor/friend.

I did a Google search "Images of dead blister beetles found in alphalpha hay" and what saw on a chart of The Life Cycle Of The Blister Beetle looked very similar. These larva like critters are throughout the bale. SB

I also found sketches, but not any quality images/photos. Unfortunately, sketches allow for a certain amount of artistic license so should not be the final word.

In any event, proceed with caution until the identification is confirmed.

The entomologist's opinion arrived today. It's good news.

"I can’t tell what those desiccated insects are for sure from the photo . . . but they look a bit like dried caterpillars. In addition, it is very unlikely that they are blister beetle larvae. Blister beetle larvae are hypermetamorphic (meaning they change form during larval development) and only the active, first instar larvae (the triungulin stage) are typically seen above ground. The subsequent larval stages are found underground associated with nests of native, ground-nesting bees or with grasshopper eggs that are laid in the soil. For larval food, most utilize the provisions and larvae of native ground-nesting bees (esp. Megachilidae & Andrenidae); several genera feed on grasshopper eggs."