Dermestid Beetle

Dermestid beetles are small beetles whose larvae eat dried animal materials such as skin, fur, feathers and dried meat. They belong to the family Dermestidae, and they are also called skin beetles. Some are household pests, while others are so good at cleaning bones that museums keep them to prepare skeletons.

Dermestid beetle Quick Facts

Common name	Dermestid beetle
Scientific name	Dermestidae
Kingdom	Animalia
Phylum	Arthropoda
Class	Insecta
Order	Coleoptera
Type	Insect (beetle family)
Diet	Dried skin, fur, feathers, wool, dead insects; adults often eat pollen
Habitat	Carcasses, animal nests, homes, warehouses and museums
Native range	Worldwide except Antarctica
Size	About 1-12 mm long
Colours	Brown, black or patterned with colored scales
Special feature	Used by museums to clean animal skeletons

A Human Skull Being Cleaned by Dermestid Beetles

There are hundreds of species of dermestid beetles around the world. The family includes carpet beetles, larder beetles, hide beetles and the khapra beetle, a serious pest of stored grain.

Description

Adult dermestid beetles are small, usually between about 1 and 12 mm long. They are oval or rounded and often covered in tiny hairs or colored scales. Carpet beetles are some of the smallest, at just a few millimeters, while larder and hide beetles can be up to about 1 cm long.

Their antennae end in a little club, and many species can tuck their antennae and legs into grooves on the underside of their body when disturbed. This makes them look like a tiny seed or speck of dirt.

Dermestid larvae are usually brown and very hairy, and many have a tuft of long hairs at the tail end. Most are less than about 1.5 cm long when fully grown.

Where Dermestid Beetles Live

Dermestid beetles live on every continent except Antarctica. In nature, they are found wherever dried animal remains collect: on old carcasses, in bird nests, in the nests of bees, wasps and rodents, and in spider webs full of dead insects.

Some species have very particular homes. For example, beetles of the genus Thaumaglossa live only in the egg cases of praying mantises, where their larvae eat the mantis eggs.

Many dermestid beetles have also moved in with people. They live in homes, warehouses, food factories and museums.

Diet

Most dermestid larvae eat dry animal matter that few other animals can digest. Their foods include:

• Dried skin, flesh and tendons on old carcasses
• Fur, feathers, wool, silk and leather
• Dead insects
• Stored foods such as dried meat, cheese, pet food, cereals, nuts and spices (some species)

Many adults eat pollen and nectar from flowers instead. Others, like larder beetles, feed on the same foods as their larvae.

Life Cycle

Dermestid beetles go through complete metamorphosis: egg, larva, pupa and adult. The length of their life cycle varies a lot. In warm conditions with plenty of food, some species can grow from egg to adult in about six weeks. Others take a year or more.

• Egg: Females lay their eggs in cracks or hidden places on or near food. The eggs are tiny and very hard to see.
• Larva: The larvae start feeding as soon as they hatch. They shed their skins several times as they grow. Some species molt many extra times, and when food runs out, some larvae can even shrink and survive for long periods.
• Pupa: Fully grown larvae often look for a sheltered place to pupate, sometimes burrowing into soft materials.
• Adult: The new adults soon mate and begin the cycle again.

Nature’s Cleanup Crew

Dermestid beetles are among the last animals to visit a dead body. After flies and other insects have eaten the soft tissues, dermestids arrive to eat the dried skin and leftovers. This makes them important recyclers in nature.

Their timing is also useful to forensic entomologists, scientists who study insects to help solve crimes. By looking at which insects are present on a body, experts can estimate how long ago a person or animal died.

Cleaning Skeletons

Museums, universities and taxidermists use colonies of hide beetles (Dermestes maculatus) to clean bones. The beetles and their larvae eat every bit of dried flesh but leave the bones untouched, even very thin and delicate ones. The photo above shows a skull being cleaned this way.

A few hundred beetles can clean the skull of a mouse or other small rodent. Larger skulls, like those of deer or bears, need thousands of beetles, with the larvae doing most of the work.

People who keep a beetle colony usually start with beetles at every stage: small, medium and large larvae, pupae and adults. In warm, dry conditions, hide beetles can go from egg to adult in about five to seven weeks, and a female can lay a few hundred eggs in her lifetime.

As Pests

Some dermestid beetles are serious pests. Carpet beetle larvae chew holes in wool clothes, rugs, blankets, furs and upholstered furniture. Larder beetles attack dried meats and pet food. The khapra beetle can destroy huge amounts of stored grain, and many countries have strict rules to stop it from spreading.

Dermestid larvae are also a big problem for museums, where they can ruin insect collections, stuffed animals and old textiles. In homes, the larvae and their shed skins often turn up where pet hair and lint collect, such as under beds, along baseboards and in closets.

How to Keep Them Away

• Vacuum often, especially under furniture, in closets and wherever pet hair collects.
• Wash or dry clean woolens before storing them, and keep them in airtight containers.
• Freeze small infested items in a sealed bag for about two weeks.
• Store dry foods and pet food in sealed containers, and throw away infested food.
• Remove old bird, wasp and rodent nests and dead insects from attics and window sills.

Mothballs and other chemical products can be harmful to children and pets, so it is best to try these simple methods first and ask a professional for help with a serious infestation.

Related: Flesh Eating Beetles

Dermestid beetle FAQs