Locust Borer

Imposter Yellow Jacket
September 11, 2009
I found this bug basking in the sun on my grape vine a few days ago. There has been a plague of yellow jackets this year eating my berries, so I assumed that this was one who had had his fill, but on closer examination, it doesn’t look like any sort of hymenopteran. It looks more like a beetle to me. Is it? Does it intentionally look like a bee/wasp/yellow jacket to ward off would-be predators?
Michael Gencarella
Post Falls, Idaho (Northern Idaho)

Locust Borer
Locust Borer

Hi Michael,
Your observation that this Long Horned Borer Beetle, the Locust Borer, Megacyllene robiniae
, is a Yellow Jacket mimic is quite astute.  The mimicry is probably most effective when the Locust Borer is feeding on the pollen of goldenrod because predators would tend to avoid what looks like a stinging insect despite the Locust Borer being perfectly harmless.

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