Beetle on lawn
Location: Bowie, MD
March 31, 2012 12:20 pm
My daughter’s (besides being totally creeped out by them) would like to know what this was.
Signature: Dan Delaney

Oil Beetle with Fire Colored Beetles

Dear Dan,
The large beetle is a Blister Beetle called an Oil Beetle in the genus
Meloe, most likely a female.  The smaller beetles are a different species, and we suspect they are not even in the Blister Beetle family.  Blister Beetles exude a compound known as cantharidin as a defense mechanism.  Chatharidin can cause blistering in skin.  The other beetles might be Soldier Beetles, and they do not have a chemical defense.  They might be harvesting the cantharidin to use since they cannot produce the compound.  We will keep trying to identify the other beetles.

Update:  March 31, 2012
Thanks to a comment from Mike, we are happy to learn that these are most likely Fire Colored Beetles, though BugGuide does not provide any explanation for this behavior.  We also found a photo of
Pedilus terminalus on Meloe posted to BugGuide and the behavior is explained here on BugGuide.

Location: Maryland

4 Responses to Oil Beetle, and Fire Colored Beetle, not Soldier Beetles

  1. mikepng24 says:

    I wonder if they could be fire colored beetles. I sent in a picture once of a blister beetle with smaller beetles all over it like this and the smaller beetles ended up being identified as fire colored beetles. I’m no expert here. I just thought I would share my experience with this phenomenon.

  2. mikepng24 says:

    Here is the link to the bugguide page on what mine were.

  3. mikepng24 says:

    Your welcome, bugman. I saw this post and it reminded me of my encounter with this behavior , so I went back and looked at my pic to see what the small beetles looked like. They were nearly identical to the ones in this post, so I thought I’d lend a helping hand.

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