Larder beetles, scientifically known as Dermestes lardarius, are common household pests that can become unwelcome residents in homes. They are part of the Dermestidae family, often referred to as skin beetles. Understanding where larder beetles originate and what attracts them indoors helps in managing their presence.
Identifying Larder Beetles
Adult larder beetles are easy to recognize due to their distinct appearance. They typically measure between 7 to 9 millimeters (approximately 1/3 to 3/8 of an inch) in length. Their bodies are dark brown to black, with a notable pale yellow or light brown band across the upper portion of their wing covers. This band often features six dark spots, appearing as three prominent dots on each side. The underside of the beetle and its legs are covered in fine, yellowish hairs.
Larder beetle larvae, the most damaging stage, are longer than the adults, reaching up to 13 to 18 millimeters (about 1/2 to 3/4 of an inch). These worm-like larvae are brownish and covered in reddish-brown or black bristles, sometimes giving them a bristly or “woolly bear” appearance. A distinguishing feature is the presence of two short, curved spine-like appendages at their posterior end.
Their Outdoor Origins
Larder beetles are scavengers in their natural outdoor environments, playing a role in the decomposition and recycling of animal protein. They are commonly found wherever decaying organic matter is present.
Their natural habitats include animal carcasses, dried animal products, and various types of nests. This includes bird nests, rodent nests, and insect colonies like wasp nests. Larder beetles also inhabit areas with accumulations of dead insects.
How They Enter Your Home
Larder beetles often enter homes during the spring and early summer months. Adult beetles are capable of flight and can travel considerable distances, often entering through open windows. They may also gain access through various structural vulnerabilities in a building.
Common entry points include cracks in foundations and gaps around window and door frames. Openings for utility lines and vents can also serve as pathways for these insects. Infested items brought indoors are another significant method of entry, such as pet food, taxidermy, or other dried animal products that may already harbor beetles or their eggs.
What Attracts Them Indoors
Once inside a home, larder beetles are drawn to specific indoor conditions and food sources. Both adult beetles and larvae feed on a variety of animal-based materials. Their preferred food sources include dried meats, cured fish, pet food, cheese, stored animal skins, leather, wool, and taxidermy specimens.
Larder beetles are also highly attracted to dead insects that accumulate within wall voids or attics, such as cluster flies or ladybugs. Dead rodents or birds located within wall spaces, attics, or chimneys provide a substantial food source. Larvae are particularly voracious eaters, infesting a wide range of these high-protein materials.