The common name “larder beetle” is used primarily for two species of dermestid beetles. Dermestes lardarius is known as the larder beetle and Dermestes ater is the black larder beetle. Both species belong to the Family Dermestidae in the Order Coleoptera. Larder beetles are widespread, cosmopolitan pests of dried animal products found in commercial and household settings.
Adult larder beetles typically measure about 0.33 inch (8 mm) long and are shaped like an elongated oval. The antennae are clubbed (Fig. 1) and short hairs cover the body.
The larder beetle (D. lardarius) has a dark brownish-black head, thorax, and the lower half of the elytra (the wing covers) (Fig. 1). The upper half of the elytra is light brown with several darker spots on each side.
In contrast, the black larder beetle (D. ater) is uniformly black to dark brown with scattered lighter colored hairs on the body (Fig. 2).
Larder beetle larvae measure about 0.5 inches (13 mm) long when mature. The body is covered in numerous long bristly hairs and two stout curving spines project downward from the top of the tip of the abdomen (Fig. 3). Larvae may appear somewhat striped with alternating dark and lighter bands across the top of the body.
Larder beetles are widespread pests of granaries, warehouses, and homes throughout much of the world. Larder beetles are also found outdoors, where they perform an important role in the decomposition of desiccated animal bodies.
Larder beetles have a complete life cycle with egg, larval, pupal, and adult stages. Females lay eggs on or near the food source. The larvae are voracious feeders. Mature larvae excavate pupation chambers in the food source or in nearby wood, plaster, and similar materials. These chambers protect the pupa from predation by other dermestid larvae. There may be several generations a year under ideal conditions of temperature and food supply.
Larder beetles feed on a wide range of animal-based foods, such as skins, bones, hides, feathers, hair, and taxidermy mounts. They also eat cheeses and cured meats, dog treats, dried pet foods, leather or wool soiled with food or body oils, and other high-protein materials. In the past, larder beetles were a frequent pest of home-cured hams. Like other dermestid beetles, they readily feed on insects that have died inside buildings, such as stink bugs, cluster flies, and ladybird beetles. Sometimes they are found in bird or rodent nests in attics and wall voids, as well as in wasp nests or unmanaged beehives. In addition, larder beetles have been reported feeding in tobacco, cocoa beans, and similar stored vegetable products, especially if contaminated with other stored product insects.
Larder beetles contaminate stored products with their feces and cast exoskeletons. They can destroy museum specimens and valued items made from leather, horn, fur, and other animal products. Mature larvae can also cause structural damage by boring into wood when preparing to pupate.
Stored product pests like larder beetles are best controlled through inspection and proper storage of potential food items. Regularly inspect for signs of feeding activity and the presence of beetle feces, cast skins, or insects. Remove and discard any products that show signs of infestation. Clean and vacuum shelving and the insides of cabinets if an infestation is suspected. Place food materials in sealed containers to prevent beetles from getting into the food, or to limit the spread of an infestation in the event that infested food is brought into the house. Keep dry pet foods in bins with tight fitting lids; spilled feed should be cleaned up and promptly disposed so it doesn’t attract stored product pests.
Taxidermy or bone mounts, products made from animal skin or hide, and decorative objects made from animal materials should be examined periodically for signs of infestation by stored product pests. Check attic spaces for bird and animal nests that might serve as a source for beetle infestations, and clean hot air registers and ductwork. Remove dead insects when found indoors. Regular inspections and good housekeeping practices will limit any infestations and eliminate the need for chemical application against larder beetles.
“Larder” is an older word meaning a storeroom or cupboard used to store foods. The term once specifically meant a cool place where cured meats were kept before the widespread use of refrigerators and modern grocery stores.
Although larder beetles can be museum pests, they are sometimes used to clean the bones of animal carcasses as preparation for natural history displays.
Theresa A. Dellinger, February 17, 2023.
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March 6, 2023