Dec 6, 2009

Fecal Encased Beetle

Case-bearing leaf beetles are known for wearing a case made from excrement until they reach maturity. Mothers make the cases around the freshly-laid eggs:

"Specifically, they compress fragments of their feces into flat squarish plates using structures in their abdomen that are part of their genitalia," said researcher Daniel Funk, an evolutionary ecologist at Vanderbilt University in Nashville.

Isn't that a fantastic quote? When the beetle larvae hatch, they don't toss aside mommy's poo case. Rather, they wear it, and even add their own fecal material to it, enlarging it as they grow.

Photo source: CHristopher Brown via

What benefit does wearing a case made of poo offer the beetle larvae? Simple: it's armor.

Researchers offered up the larvae to three would-be predators: the spined soldier bug, the common cricket, and the lynx spider. In most instances, the predators simply ignored the larvae, assuming that no creature would choose to live in poo. Those that did notice the larvae usually hesitated, which gave the larvae a chance to scamper away to safety.

Among those who actually attacked the larvae, they were usually thwarted by the armor. Since the beetle excrement ultimately came from plant matter, it still contained much of the plant's protective juices (think chile heat). Some beetles even coated the armor in sycamore fibers, which is known to kill crickets.

I'll tell you what, nature never ceases to amaze me. I would never recommend wearing your own poo, but in the case of this beetle, it's hard to argue with survival.

And please, no one mention this to my toddler son. He's just learning how to take off his diaper, and he doesn't need any more convincing that wearing his own poo is a good idea.

Thanks for the link, Ida.


Rosewolfkin said...

That's amazing - gross - but amazing.

And I hear ya about the toddler! My own son is 19 months and he's done this twice to us...and thought it hilarious each time. ERGH!

Always beware when a toddler not only lets you sleep in...but is quiet.

morgan said...
This comment has been removed by the author.
morgan said...

"I would never recommend wearing your own poo, but in the case of this beetle..."

Ohhhh my goodness. Terrible. Just terrible.

Also, I had no idea crickets were vicious predators! I used to feed crickets to my gecko, whose lightning-fast snarfing made them seem pretty helpless. I guess I'd change my tune if I were small enough to fit in a cricket's mouth...

Adorably Dead said...

Ick a poo beetle.