Tuesday, December 19, 2006

Mystery Solved

Earlier this month, we found a group of black insects eating the remaining flesh off of a dead fawn's lower jaw. The creatures consisted of black plates that widened from the head to the thorax and then tapered rapidly to the end of the body. Six legs were located under the widest portion of the body. They moved away rapidly when disturbed. The image shows one that was captured for identification and stored in alcohol. The legs are curled underneath the body.

There are a multitude of insects that arrive at a dead body and aid in the recycling of the soft tissues. We search but could find nothing that resembled our specimen. Finally, a search of images on the web revealed that our specimen was not an adult, but the larva of a carrion beetle, which are difficult to identify if they are not allowed to mature to an adult.

The second image shows one possibility. Adult American Carrion Beetles (Necrophila americana) are shown last summer eating and mating on the carcass of a raccoon near #9 on the boardwalk. The adults will lay eggs on or near the carcass and dine on fly larvae to reduce the competition for their own larvae. The beetle larvae will feed in or under the carcass and on fly larvae. The beetle larvae will pupate in a soil cell nearby.

Although this topic is not appetizing for humans, the variety of carrion insects help keep the environment from becoming knee-deep in smelly carcasses.

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