Hide beetle (Dermestes maculatus)


In nature, adult Dermestid beetles (also known as hide, carrion, or skin beetles) are often found beneath dead animals that have decomposed for several days to weeks.  They are generally small ( about 2 to 12 mm in length with the female larger than the male), black or dull in color, and usually hairy.  The larvae are also usually brown in color and hairy.  Dermestid beetles are often utilized to clean soft tissue from skeletons, and are especially valuable in cleaning those of small animals with delicate bones.  They can clean a skeleton perfectly, while many chemicals treatments can cause the bones to yellow.  You just need enough patience to let the dermestids work.  For these reasons, science professionals, most museums, and most universities frequently grow colonies of these hardy, easy-to-maintain insects.  Though dermestids (which take their name from the Greek word dermis, or skin) have potential for destruction of woolen fabrics, furs, insect and animal collections, and many other common materials, unwanted infestations are easily prevented through reasonable care and containment of colonies.

Availability: These need to be ordered and will be available after spring break.

Housing: Raise your dermestids in a jar, cup, or bucket.  Raise them in a hard plastic, glass, or metal container to prevent them from escaping.  Put a screw top or wire mesh lid on your container.  If using a metal lid, poke a few very small holes in it.  Place wood shavings (not sawdust) to a depth of 1/2 inch in the bottom of the container.  Place a foam block over the shavings and a sponge on top of the foam block.  Add your dermestids and spray the container with a fine mist of room-temperature water so they whole container is moist but not soggy.  Place in a warm dark place for 24 hours so the beetles can adjust to their new surroundings.  After 24 hours the culture should smell moist, but no condensation should be visible in the container.  If the culture is too moist (visible condensation), leave the cup lid slightly opened for 24 hours.  If it is too dry (does not smell moist), respray with water.  Continue to maintain the colony in a warm, dark place and check it every three to four days.  Soon small larvae will appear on the sponge and begin pupating in the foam block.  Adult females produce eggs five days after emergence.  Under ideal conditions, each female should produce several hundred eggs.  Therefore, at an optimum temperature of 85 degrees F it takes approximately 45 days to produce one full generation of beetles. 

The health of the colony depends upon proper levels of food, moisture, and fat.  For example, too much moisture may result in molding and too much fat may prevent hatching by saturating the eggs.  Conversely, too little moisture or fat will inhibit egg laying.  Colonies are susceptible to mites.  Check beetles for mites under a microscope, be sure to examine the legs and the area between the head and the thorax especially closely.  A mite infestation indicates that the level of moisture is too high.  If you discover it in an early stage, you can end an infestation by decreasing the moisture.  However, if decreasing the moisture does not work, then you will need to destroy the colony and start afresh. 

Food:  You will receive dermestid food with your beetles.  Place a small amount in the container between the wood shaving and the foam block before you add your beetles to the container.  The larvae will eat the sponge in the container.  You can place a small dead animal into the container if you wish to have a skeleton cleaned.  Just remember that it will smell, and that you need to be extra careful about the amount of moisture in the container.  You will also need a large colony.  Dermestids are later-stage decomposers, they will not eat a fresh body.  You will need to skin it, remove the organs, blood, all large muscle masses, and you will need to air dry the body for a few hours.  Ask one of the TAs on how to do any of this if you are unsure.  You may want to put the colony and specimen to skeletonize in a shallow cardboard box to keep the pieces together.  If you want to mount the skeleton, check it every day to make sure that they beetles have not reached the point of eating the joints and other connective tissue.