Turns out I don't like big butts at all!
|Image: Chris Moody|
Violet Oil Beetle (Meloe violaceus)
Despite their extraordinary waistline the "Oil" in question is not some awful cooking oil which turns your brain to mush and then puts it on your hips. Rather, it refers to the oily droplets of blood they release from their joints when disturbed. This is already queasy, but even worse is the fact that the stuff contains a poisonous chemical called cantharidin, which is potent enough to cause blistering in human skin.
Red-striped Oil Beetle (Berberomeloe majalis)
Others are... different.
|Image: José María Escolano|
Oil Beetles look like that all the time! Even the males! Although they aren't quite as chunky as the females. Still, it allows some Oil Beetles to produce up to 10,000 eggs. You need a lot of room to carry that kind of weight!
Video: Serbal Almeria
In some ways, Oil Beetles look even worse than the Leaf variety. Their body is much longer and bulges horrifically all the way down. Some are so long that half their body has to be dragged along the floor. They also have no wings, and the wing cases seem to have accepted a purely ornamental role and have shrunk right down so they barely cover anything at all.
On the other hand, at least the abdomen doesn't look quite as stressed and strained and ready to burst! With Leaf Beetles, their abdomen expands during their adult life and the skin around their abdominal, exoskeletal plates stretches so thin that it can become translucent. Sometimes you can just about see the eggs inside.
Oil Beetles, on the other hand, are big and bulging as soon as they enter adulthood, so they don't have to stretch their skin to breaking point.
Speaking of entering into adulthood, one interesting thing about Blister Beetles is that they're hypermetamorphic.
Most of the insects that go through metamorphosis start out as some kind of larva, like a maggot or caterpillar, which eats and eats until it's big enough to pupate and develop into an adult.
Oil Beetles, like other Blister Beetles, are different. They have an entire, extra larval stage!
|Image: Malcolm Storey|
The triungula start their life in a hole in the ground previously excavated by their mother. In some species, the triungula will climb out and simply scamper away in search of grasshopper eggs to feed on. In most species however, their mother has been careful to dig her nest near to those of ground-nesting solitary bees.
The bees pack their own nests full of pollen to serve as food for their young. In another world perhaps our Oil Beetle would have done that for her own children. But she doesn't have wings any more and besides, 10,000 mouths to feed is a lot of work.
|Image: Malcolm Storey|
Triungulin clinging to a bee
Some Oil Beetles add insult to injury, or deception to murder. They're not interested in waiting about in a flower hoping that the right kind of bee will happen along. They take a more proactive approach to the whole affair.
They don't go to the flowers, instead they gather together in writhing blobs near the tip of stalks and leaves. Together they produce a pheromone which mimics the one produced by a female bee who's interested in some male company. A male duly arrives. He must be excited beyond all reason or like, doesn't know what a bee-woman looks like, because he immediately attempts to mate with a ball of limbs and lots and lots of mouths to feed.
|Image: Leslie S. Saul-Gershenz and Jocelyn G. Millar|
|Image: Durlston Country Park|
After all that crazy it's back to good old pupation and adulthood. Phew!
Black Oil Beetle (Meloe proscarabaeus)
It has it all; sex, murder, deceit, betrayal, lice and more. And what a character arc! Who would think this bulging creature could have started out life as a minute louse racing up a plant so it can grab onto the hairs of a bee and hitch a ride? It doesn't seem possible. Even if they do look like they're full of helium.