Asked November 06, 2020, 6:08 PM EST
Calhoun County Michigan
That is a larder beetle larva, Dermestes lardarius (Coleoptera: Dermestidae).
Both the larvae and adults feed on items such as fur, hair, dander, hides, feathers, and occasionally stored products such as dried fish, pet food and cheese. In the house, a likely source is dead insects or other animals (boxelder bugs, attic flies, ladybugs, mice, etc.) that have passed away inside walls or attics. This beetle is also found in bird nests, animal remains, and bee and wasp nests.
The adult beetle is just under 3/8 of an inch long and dark colored with a pale yellow band across the center of the beetle. The grub or larva is dark brown and very hairy in appearance with 2 curved dorsal spines on the tail end. There may several generations of the beetle each year. The larvae are known to burrow into wood to construct chambers in which to pupate. We have some reports of structural damage to hen houses because of this behavior and in these cases the most destructive phase of the life cycle occurs when the larvae pupate. It appears that the preferred pupation site is soil where the larvae chew out a small pupation chamber. In the absence of soil, the pupation chambers are constructed (chewed) in wooden structures or insulation inside walls and ceilings.
The first step in larder beetle control is to locate and dispose of all infested material. This may be difficult or next to impossible if the beetles are feeding on dead insects in wall voids and other hidden sites. After the infested material is removed, the immediate area should be thoroughly sprayed with an indoor formulation of permethrin (sold under a variety of brand names including raid in the blue can) or bifenthrin (sold as Ortho Home Defense Max). Do not use these products in cupboards or food preparation surfaces. When they are found in cupboards, all food material should be inspected and discarded if found to be infested.
Be sure to read and follow all instructions and safety precautions found on the label before using any pesticide.