What's That Bug? does not endorse extermination

Subject:  Green blister bug?
Geographic location of the bug:  Isle of Wight, UK
Date: 05/25/2019
Time: 02:17 PM EDT
Your letter to the bugman:  Hi, found this bug near Orchard Bay on the Isle of Wight in England. From googling it looks like a green blister bug, but they don’t seem like they’re in the UK?
How you want your letter signed:  Jack

Spanish Fly and Soft Winged Flower Beetle

Dear Jack,
This is a very exciting posting for us.  We believe your Blister Beetle is the true Spanish Fly,
Lytta vesicatoria, which is pictured on UK Beetle Recording with some southern sightings including the Isle of Wight.  According to NBN Atlas:  “Spanish fly is an emerald-green beetle, Lytta vesicatoria, in the blister beetle family (Meloidae). It and other such species were used in preparations offered by traditional apothecaries, often referred to as Cantharides or Spanish fly. The insect is the source of the terpenoid cantharidin, a toxic blistering agent once used as an aphrodisiac.”  GBIF has an interesting article.  We are very curious about the smaller beetle in your image, which though the coloration is the same, appears to be a different species.

Hi Daniel,
Thanks for getting back and helping identify the species in the photo, the links you included are interesting. There were more than just those 2, there were 10-15 of the smaller ones, all on the same flowers as in the picture. Took a photo of that one as it was the biggest by far, probably about 2 inches.
I didn’t think much of the size difference and just figured it was age/maturity, but am also intrigued having now looked at the life cycle of a beetle? Am I right in thinking they’d emerge from the pupa at their fully grown size?
Many Thanks,
Jack

Hi again Jack,
When insects including Beetles emerge from the pupa, they are fully grown.  Smaller individuals probably did not feed as well during the larval stage, hence the smaller size.
Update:  June 20, 2019
Thanks to a comment from Jim, we now know that the smaller beetle is a Soft Winged Flower Beetle in the family Dasyticidae:  Psilothrix viridicoeruleus.  There are images on UK Beetle Recording.

What's That Bug? does not endorse extermination
Location: Isle of Wight, UK

6 Responses to Spanish Fly and Soft Winged Flower Beetle found on the Isle of Wight

  1. JimB says:

    Hi Jack and Daniel,
    As the Coleoptera county recorder for the Isle of Wight I would love to include Jack’s sighting in our county records. As beetles are under-recorded on the Isle of Wight I need all the records I can get!. I am trying to ascertain whether this species is maintaining its small population or if it is increasing after being first reported over ten years ago. Many thanks, Jim

  2. JimB says:

    Hi,
    For your information I have investigated the photo of the beetles further and I have been advised that the smaller beetles with the Spanish Fly (Lytta vesicatoria) are a different species as you originally suspected. They are Psilothrix viridicoeruleus, from the family Dasytidae, and are found along the coast of the Isle of Wight and southern England.
    I hope this helps.
    Best wishes,
    Jim

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