I discovered my first American carrion beetle in June of 2012, in its larval form. Did I know I had stumbled across a carrion beetle? No. In fact, I was not sure I'd stumbled across a beetle. I am fascinated by life in the leaf litter and on the forest floor - and so, when I noticed a small, black, beetle-like creature scuttling across the trail before me, I stopped. I knelt down to take a closer look...
The creature appealed to me because it reminded me of a pill bug (you see, roly-polies, are my favorite little decomposers). Unlike a roly poly, this seemingly armored beetle was elongated and pointed at its posterior. I snapped a couple photos with my point-and-shoot and carried on.
It wasn't until a couple years ago - when I made a weak attempt at accurately identifying all of the fungi, plants and animals I had ever photographed - that I learned the odd-looking black beetle I'd met in Swatara State Park was in fact, the larva of the American carrion beetle!
Necrophila americana is a North American beetle, found in most of the United States and southeastern Canada. I have read it prefers the damp woods, but it has also been discovered living quite contentedly in grassy meadows. Of course, the most interesting part of the carrion beetle is its life cycle...
American carrion beetles appear to mate only in the presence of dead/decaying animals - romantic, right? Well, although pretty creepy, it's kind of required. The female lays her eggs in decaying matter so her wee little babies have something to eat when they hatch. In fact, she is such a good mama she also considers her babies when it comes to other equally discerning potential parents - flies. Carrion beetle parents stick around their carcass love nest eating hatching fly larvae until their own eggs hatch and then the Necrophila americana larvae eat both the carcass as well as any remaining fly larvae! When the larvae have had their fill they fall to the ground, borrow into the dirt and pupate.
As you can see in the photograph above of the adult carrion beetle, they do not shy away from scat. I have not done extensive research, but I am going to make an educated guess and say that this life cycle might also take place in animal waste, not only decaying flesh. And you thought the carcass-love-nest was romantic? They are really rather fascinating in the fact that they discover decaying organic matter using olfactory receptors in their antennae. According to one source, it takes between three and five days after the death of a food source for N. americana to locate it.
You might be thinking my reference to mutualism above refers to the relationship between the deceased animal and the carrion beetle. Nope. It instead has to do with a tiny mite (Poecilochirus spp.) who stows away on adult carrion beetles and travels from carcass to carcass mimicking the exact same behavior as the beetle - eating the eggs of previous visitors (i.e. flies), laying its own eggs and then...returning to the adult beetles to be taxied to the next carcass! Isn't nature inexhaustibly interesting?
[References: www.wikipedia.com, www.bioweb.uwlax.edu]