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Fred's Bughouse Blog: Blister Beetles Part Two

Updated: Apr 10

In the first part of our soul-shaking blister beetle expose, we looked at the b-a-n-a-n-a-s natural history of the beetles in the family Meloidae. That story, which included characters like the vicious little "triungulin" and its heartless exploitation of baby bees, led us up to the highly toxic blister juice that oozes out of these insects' knees. So let's get up close and personal with these little monsters -- but be careful not to get any on you...


When blister beetles aren't busy being terrible, they're busy being gorgeous.


The name “blister beetle” is richly earned. The insect secretes a substance called “cantharidin,” which is a milky poison that oozes out of the bug’s knees. Because they’re so toxic, blister beetles are usually brightly colored, which is called “aposomatic coloring.” This term refers to colors and designs meant to warn away birds and other threats. Lots of animals, especially insects, use aposomatic coloring. Blister beetles are also soft-bodied, which makes sense, because you don’t need a hard protective shell if no one’s trying to eat you.


Cantharidin is something else. I could tell you what happens when you mess with a blister beetle, but it’s easier to just show you:


What you get from messing with a blister beetle


These nasty blisters are painful, but won’t typically send you to the emergency room. But trying to use blister beetle juice to achieve an erection quite possibly will -- and might even kill you. It turns out that tangling with your grandfather’s wiener pills is extraordinarily dangerous.


We’re talking here about the legendary “Spanish Fly,” which is actually two things: 1. A fake boner pill that you used to be able to send away for in the back pages of awesome publications like True Detective and Sir!, and 2. An actual insect, the blister beetle species Lytta vesicatoria. The “aphrodisiac” you could buy in magazines was a spurious concoction that simply didn’t work – in fact, the ads would use the word “spurious” as if it meant “super-effective,” trusting that their readers wouldn’t have the word in their vocabulary...


But blister-beetle Viagra actually does have a basis in fact. Crushed-up L. vesicatoria beetles have been used as an aphrodisiac, among other things, for a very long time in Spain, and also much of Europe. The reason it’s used as an aphrodisiac is this: When men ingest cantharidin, it irritates their insides, especially the bladder and urethra, which results in, you guessed it, swelling. So Spanish fly actually does give you a boner, but it’s not the good kind of boner – it’s a painful side effect of a destructive, system-wide, sometimes-fatal poisoning. So no, Spanish fly isn’t sexy. Unless peeing blood is sexy.


The real Spanish Fly, Lytta vesicatoria


I don’t normally quote Wikipedia, but this bit about the system-wide wrecking ball that is blister beetle juice is worth it:


“Cantharidin is dangerously toxic, inhibiting the enzyme phosphatase 2A. It causes irritation, blistering, bleeding and discomfort. These effects can escalate to erosion and bleeding of mucosa in each system, sometimes followed by severe gastro-intestinal bleeding and acute tubular necrosis and glomerular destruction, resulting in gastro-intestinal and renal dysfunction, organ failure, and death.”


I don’t know what “acute tubular necrosis and glomerular destruction” is, but I do know that no boner is worth risking it.


Enough, you say? Ha ha, says the blister beetle. Turns out that there are species of Meloidae in the western United States that feed not on bees but on grasshoppers. The process is basically the same, with fast-moving, hungry triungulins chasing down the grasshoppers, riding them to where they lay their eggs, and eating the eggs and immature grasshoppers. The adults emerge from the ground to feed on forage plants like grasses and alfalfa.


Proof that you can't out-run your problems: a racehorse at risk of being killed by a blister beetle.


So far so good. The trouble begins when the forage is harvested to feed livestock, specifically horses. The beetles get swept up and crushed in with the horse fodder, and if you read the above bit from Wikipedia, you’ll know that’s going to be problematic. Sure enough, horses that eat the beetle-filled fodder are often poisoned. In some cases, they die. Blister beetles have killed prized race horses.


There’s more -- people dying after being secretly dosed with Spanish fly at a bar, for example -- but I need to make room in the Bughouse for more amazing creatures, so we’ll stop here. Stay tuned for the next post/episode, when we’ll look at another amazing (and probably fairly disturbing story from the Kingdom of the Bugs.


See you soon!

Fred

Sources:

http://entnemdept.ufl.edu/creatures/urban/medical/blister_beetles.htm

https://entomology.ca.uky.edu/ef102

https://entomology.ces.ncsu.edu/2015/09/blister-beetles-of-hay-and-forages-in-north-carolina/

https://www.sciencedirect.com/science/article/pii/S0022191012000455

https://en.wikipedia.org/wiki/Spanish_fly

https://www.paulickreport.com/tag/blister-beetle/

https://www.latimes.com/science/sciencenow/la-sci-sn-blister-beetles-bee-parasites-20180912-story.html

https://www.timesobserver.com/sports/outdoor/2019/10/the-surprising-life-of-the-oil-beetle/

http://www.biodiversityexplorer.info/beetles/beetle_larvae_mimic.htm


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