Telling apart the subspecies: in A. u. unicolor, the pronotum and elytra are almost entirely covered with dark setae; in A. u. japonicus, the sides and base of the pronotum and the base of the elytra have distinctive golden brown setae.(1)
adventive and widespread in NA(2)(1), native to the Old World (origin unknown; non-native in Europe), now nearly cosmopolitan(3)(4)
Outdoors it occurs in the nests of birds, wasps/bees, and rodents; infests domestic and commercial locations(5), incl. grain elevators, flour mills, feed mills, and museums(1)
Larvae feed on animal materials (silk cloth, wool, feathers, hair, fur, fishmeal, eyc.) and cereal products; adults feed on pollen of various plants outdoors(5)
One of the most common household pests in NA (the damage is done by the larvae only); attacks museum specimens, esp. dried insects(1) Has been reported to damage books; pest in Japan's silk industry. Larvae often bore into food containers, making food vulnerable to infestation by other pests. When disturbed, larvae curl and remain motionless for a long period.(5)
Disclaimer: Dedicated naturalists volunteer their time and resources here to provide this service. We strive to provide accurate information, but we are mostly just amateurs attempting to make sense of a diverse natural world. If you need expert professional advice, contact your local extension office.