The females lay up to 200 eggs on materials such as hides and skins which are suitable for larval development. They are white, 2mm in length and often laid in the crevices of commodities. The larvae, which hatch out in about a week, are dark brown, hairy and feed on almost any dry or decomposing animal material. They will occasionally feed on vegetable matter. They are very active, and will avoid light, frequently boring into commodities to do so. If disturbed they will curl up and feign death. There are usually 5 or 6 moults and the full grown larva is 10-15mm in length. When mature the larvae often leave the foodstuff, and will excavate holes in hard, inedible material in order to pupate. The burrows created for this purpose may be up to 30Omm long. Alternatively, pupation takes place deep inside the infested commodity, or it the larvae are forced to pupate in the open they do so inside the last larva[ skin. The speed of larval development depends upon conditions and may extend beyond a year. Generally the pupal stage is completed in 2-4 weeks and the full cycle in 2-12 months.
Dermestes literally means 'skin-eaters', and this is precisely what the beetles do. They play only a very minor role in disease transmission, although they may act as mechanical vectors of anthrax. They will breed on any animal protein and can be a serious pest in hide warehouses, tanneries, milk-processing plants and other premises where animal products are processed.
Damage is caused by the larvae which bore holes in materials, either as they feed or in order to pupate. The soft sapwood of wooden structures are preferred pupation sites. They will also excavate plaster, lead and tin, but not zinc or aluminium. Similar damage to stored commodities may also be caused by the adult beetles.