Overwintering pests as dermestid snacks

You see lady beetle carcasses; dermestids see lunch.
Photo: Mark Sheperdigian

Multi-colored Asian lady beetles (Harmonia axyridis), brown marmorated stink bugs (Halyomorpha halys) and cluster flies (Pollenia spp.) are just a few of the insects we call overwintering pests. They enter homes and other buildings in the fall for a quiet place to spend the winter. In the spring, they rouse, exit the building and go about their business.

However, many of them don’t make it through the winter, and a pile of carcasses builds. As every insect collector knows, there are several dermestid beetles — most notably, the warehouse beetle (Trogoderma variabile) — that will breed on dead insects.

In this photo, we see lady beetle carcasses from years gone by being converted into a feast for warehouse beetles. When you’re looking for a source of dermestids, consider the possibility of overwintering insects in attics and wall voids. Also check light diffusers, lamp globes and window sashes for trapped insects as well.

Contributor Mark Sheperdigian can be reached at shep@rosepest.com.