Of the massively diverse insect order Coleoptera (beetles), the dermestids are undoubtedly one of the most commonly encountered beetles in the urban environment. But, they are easily overlooked because of their small size and often hidden feeding habits.

The Name Game.

Dermestids, individuals in the family Dermestidae, are commonly known as skin or carpet beetles. The latter is a terrible name as the vast majority of floor coverings are now made of synthetic, non-edible fibers that have nothing to do with these beetles. Referring to dermestids as “carpet beetles” frequently confuses clients and requires further explanation.

If the moniker “carpet” is out, then what is the “skin” name all about? A novice might assume that dermatologists would study dermestid beetles. But, this absurdity merely stems from the commonly shared Greek root word, derma, meaning skin. Then, why would a group of beetles be called “skin” or “hide” beetles? This name is really an oversimplification of the dermestid diet. Many of these beetles do feed on old animal skin, but the term “broad palate” is an understatement for this group as they will eat just about anything! In fact, dermestids can find nutrition in many items including stored grains, pastas, cured meats, spices, natural fabrics, feathers, blooming flowers, dirtied incinerator shafts, museum specimens, dead insects, feces and carrion. It’s quite an appetizing, and varied, list!

For those of you without carrion at your residence — don’t assume that only hunters and Hannibal Lecter-types need to worry — instead, think of mammal (mainly rodent) or bird nests that are located within structures, and what happens when these animals expire. Dead insects, another favored food source, become associated with humans in a variety of scenarios, too. In fact, as a young proto-entomologist I was traumatized by dermestid beetles and their bizarre palates as they turned my prized insect collection into an open buffet line, morphing beautiful specimens into hollowed out husks with piles of chitinous debris beneath! For those without intentional insect collections, dead insects may accumulate in structures from overwintering insect problems or cavity-dwelling social insects.

Of course, the more scientific term, dermestid, is not a household name and will not educate the client about their habits either, but it does benefit from being taxonomically accurate and lends a certain resonance of professionalism and knowledge — so let’s use that as our starting point.

Dealing with Dermestids.

Dermestids are probably the most common specimens that are brought in to our offices for identification. The concerned client may wonder if the unidentified insects are bed bugs, after finding them in their bedroom. These are often black carpet beetles or another species that will feed on old sloughed skin or hair and were — I proceed to tell the (often squeamish) specimen submitter — absolutely there to feed on them! Not their living body, but the “them” of days gone by.

Many of us know that we store items from the past under our beds, but this can get a little creepy when you think about storing your old skin there. At this point it is often a good practice to bring the concerned resident up to speed on the latest in pest management technology and techniques, focusing on vacuum cleaning and regular bed linen washing. If you didn’t think that cleaning your room was good pest management, think again! It is important to note that while the above-mentioned scenario is common, it isn’t the only possibility.

This group of beetles is important to our industry because there are totally opposite extremes their presence can signify to a pest management professional. On the one hand, it could be an isolated incident — no big deal — flick the offending beetle into the toilet and carry on. However, if the dermestid is the feared Khapra beetle, for example, call the USDA! We’re gonna need this building quarantined until total elimination is achieved!

There are also a number of situations where finding dermestids in a structure will fall in between these two extremes, when some control measures would be appropriate.

So, if you find yourself looking at a small beetle and you’re not sure if it is a dermestid or not, consider a few things:

  • Is it less than ½-inch long?
  • Do the wing covers have hairs or scales?
  • Are the beetles all black in color or, if not black, have multiple colors on their backs?
  • Are the antennae clubbed?
  • Does each leg (front, middle and hind) clearly have five tarsal segments?
  • Is the head largely concealed when viewed from above?
  • Do the beetle’s legs fold up flat against its body when disturbed (or dead)?
  • Was it found in close association with slow-moving, fuzzy larvae?

If six or more of these questions can be answered with a “yes,” it is very likely that you are dealing with a dermestid.

To be continued…read next month’s Tech Talk column for more detailed identification information and appropriate control measures.

The author is manager of education and training for Rose Pest Solutions, Troy,