What's That Bug? does not endorse extermination

Who’s eating my marigolds?
July 21, 2009
Hello! These guys arrived 3 days ago. I thought they were lightning bugs at first. The are buried in each marigold bud and sucking the life out of them. Like a plague of locusts, they have destroyed all the blooms, and there were many! We’ve used several different repellent sprays, nothing keeps them away for long. Thank you for caring! It is appreciated. (Been searching the web for hours to no avail.)
Joanie B.
Eastern Shore of Maryland (Willards, MD)

Unidentified Blister Beetle

Unidentified Blister Beetle

Hi Joanie,
This is a Blister Beetle in the family Meloidae, but we have not had any luck identifying the species on BugGuide.  Adult Blister Beetles often feed on flowers and foliage, but in the larval form, they often have complex parasitic life cycles with hosts that include bees and grasshoppers.  According to BugGuide:  “Pressing, rubbing, or squashing adult blister beetles may cause them to exude their hemolymph (“blood”), which contains cantharidin. This compound causes blistering of the skin, thus the name blister beetle. Accidental or intentional ingestion of these insects can be fatal. There are documented incidents of horses dying after eating hay in which blister beetles were inadvertently baled with the forage. Watch that curious children do not attempt to put these beetles in their mouths. The external use of cantharidin, commercially known as ‘Spanish fly,’ the supposed aphrodisiac, is likewise discouraged.”  We hope one of our readers will be able to supply a species identification, or at least a genus identification.

Unknown Blister Beetle
July 23, 2009
Hi Daniel:
It does look like a blister beetle and I can’t claim to be an expert, but this looks a lot like a species of Epicauta, particularly E. hirticornis. The problem is that this is an Asian species and I haven’t found any record of it becoming an invasive in North America. There are a few other red headed species in the genus but none appear to be endemic to the USA; in fact I haven’t been able to find any North American blister beetle that looks quite like Joanie’s photo. I may be on the wrong track here, or it may be possible that these guys do not belong. I think I will keep looking, but this looks like a job for a real expert. Regards.
Karl

Update from Karl
Hi Daniel:
Can I retract? Some further searching did yield one indigenous species that looks like Joanie’s blister beetle, Epicauta trichrus, although the overall shape and some of the coloration still don’t look quite right. I couldn’t find much information about this species but it has been recorded from Massachusetts, so why not Maryland. I found it on Bugguide.net (where else) – I don’t know how I missed it first time through. In fact, the Bugguide site has a second species. E. atrata, that also looks similar, although apparently the head is usually black and only sometimes reddish behind the eyes. Although to me Joanie’s photo still looks more similar to some of the Eurasian species it makes sense to take the more conservative approach and assume that it is not an introduced species. Regards.
Karl

Thanks Karl,
We looked at those two species and decided they were not Joanie’s beetle, but we may be wrong.

What's That Bug? does not endorse extermination

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