The world needs animals willing to clean up all the dead, smelly things nature leaves behind. The American Carrion Beetle (Necrophila americana) is one of those animals. It is a fairly large insect at up to 20 mm in length. As in the picture, they are black and yellow in color. They can fly, and some say they resemble a bumblebee or carpenter bee in flight.
The adults eat fly larvae (aka maggots) that are feeding on carrion (aka dead animals). They will also eat some of the carrion. Adult carrion beetles may also eat fungus and sap from tree wounds. The larvae eat carrion, maggots and beetle larvae. After the fly larvae leave, they will eat dried skin and bits of flesh.
They have an interesting relationship with flies. Usually the flies arrive at the carcass first, and the adult beetles will not be too far behind. They will eat the already hatching fly larvae, start mating, and lay their own eggs. This will continue as long as the carcass lasts. The adults will eat competitors to give their own larvae a chance to eat and grow. Larvae will hatch in a few days and feed in or under the carcass. They then go into the soil and pupate. They will overwinter as adults.American carrion beetles have a mutualistic relationship with some mites. The mites are carried on the beetle, and will drop onto the carcass when the beetles get there. The mites will eat the eggs and larvae of the flies that are already there. They will also start and continue to lay eggs. Eventually they will return to the adults and hitch a ride to the next carcass. Some of the mite young will also hitch a ride with the beetle young when they emerge from the pupal state.
As might be expected, June through August are the prime months for finding these beetles feeding on carrion. March all the way through September would be the months you could see them.
The adult beetle pictured above was found in my backyard in Ottumwa. I don’t know what it had found to eat, but there were no dead animals nearby. I have seen pictures of them feeding on watermelon. Maybe they found something in my compost bin they thought smelled and tasted good. If you follow our “What Is It Wednesday” on Facebook, that picture should look familiar.
Spend a little time outdoors, and you might find something you never expected.