I first heard about dermestid beetles in 1993, while taking a college ichthyology (the study of fishes) class. To learn the many bones of a fish’s head, we were tasked to fully articulate or clean a fish head of our choice. Most of us simply started to pull the flesh from the head exposing most of the bones. It was a tedious exercise, but I can still tell you what the quadrate bone looks like.
When we handed them in, I noticed one young lady’s fish head looked exceptionally clean and professional. The other heads were a collection of semi-cleaned, greasy bones all glued together. I asked her how she had gotten the bones so clean. She looked at me and simply stated, “I used dermestid beetles.”
After college, I started hunting more, and I wanted to start producing my own European mounts of the animals I harvested. I remembered seeing how well the dermestid beetles had done on the fish skull and started investigating what it took to keep and culture the small larder beetle.
While I was able to obtain a very small quantity of bugs from a biological supply company, there was surprising little information out there on how this beetle-cleaning process worked. With only one instruction sheet included with my order, I knew much of what I was going to learn would be by trial and error.
The instruction sheet did state that the bugs work best at temperatures from 70 to 80 degrees F. It also stated that you needed to keep the colony dry and relatively clean. That was about it. No real feeding instructions, maximum or minimum temperatures, nothing on how they can chew through anything that isn’t glass or metal, no enclosure suggestions or how to deal with potential pests. When I started all this in the mid-’90s, I was essentially on my own.
I started by keeping the colony in a small plastic bin with a small ventilation hole. I soon realized these bugs require a lot of ventilation, and if they don’t get it, they don’t clean efficiently. Fixing that problem, I started tossing in upland bird heads into the colony and they did well. After a successful pheasant hunt, I simply added three bird heads, feathers and all into the colony. The next day, almost the entire colony was dead.
Continuing to search for answers, I found that ground birds such as quail and pheasants usually carry dust and dirt mites in their feathers, and that these parasites are deadly to dermestid beetles. Dropping in recently killed game bird heads, feathers included, was a recipe for disaster. After that, I would skin everything and freeze it for a few days before giving it to the colony.
After the first year, I began to figure things out. Using heat lamps, I could keep the colony working and reproducing year-round. I moved the colony to a larger aquarium with a screened lid. With the increased surface area in the new aquarium, the bugs exploded in number. I soon picked up a second aquarium.
Over the years, I have greatly expanded my colonies and have cleaned every North American animal available to hunters, from elk to mourning doves. I set up a website in 2004 called Dermestid Inc. and have been selling these unique bugs all over the globe since then. I was even interviewed for a Korean version of Dirty Jobs and was featured on an episode of that weekly show, aired, of course, in Korea. I was the only one featured who spoke English.
As a biologist and hunter, I’ve always been fascinated with animal skulls. Culturing and keeping these bugs have allowed me to maintain an extensive collection of every single species I’ve hunted over the years. I’ve also learned a great deal about how to culture and use dermestid beetles. If you follow some simple rules, they are as easy to handle as goldfish. Here’s what I’ve learned.
Primary Beetle Care
Learning from my early mistake, I now make sure each and every item I put in with the bugs is skinned and frozen for several days prior. I also stay away from dirty skulls, such as roadkill or hunted skulls that are left out and neglected. If the skull has had prolonged exposure to dirt or the ground, I won’t clean it. I tell anyone who wants me to clean their trophy, that they need to skin it and immediately place it in the freezer.
A consistent temperature for these bugs is also very important. As stated, I use heat lamps to maintain the preferred temperature of 70 to 80 degrees F. I’ve found that they really clean a little better above that temperature at around 85 degrees. If the temperature dips below this window, during colder periods of the day, the beetles will not clean skulls well and their breeding will drop off substantially. When I get questions about a lethargic colony that isn’t performing, the first thing I ask is if the temperature is consistent.
Another important factor for beetle culture is ventilation. These bugs respire or breathe a lot and making sure they have plenty of fresh air is essential for keeping them healthy and reproducing. If the ventilation is insufficient, condensation will accumulate inside the colony, keeping it damp, and the colony will produce an ammonia smell. Both these issues will bring a thriving colony to its knees.
Other than food prep, temperature and ventilation, these bugs are surprisingly easy to raise. I currently have six huge colonies that supply the website orders and clean my own skulls.
Two Basic Life Stages
There are two basic life stages of the dermestid beetle: the fuzzy, caterpillar-like larvae and the dark adult beetle. The larvae are the workhorses of your colony and responsible for almost all the skull cleaning. They go through seven growth stages over a 45-day period when they shed their outer skin. Once they go through the larval stage, they wrap themselves in a cocoon and develop into a black adult beetle after about seven days.
The adult dermestid beetle spends its four-month lifespan reproducing and laying eggs. They are usually the first to find the uncleaned skull and will lay eggs on or near the skull. The eggs take two days to hatch, and the larvae come out hungry. From start to finish, each dermestid bug lives for about five to six months.
Skull Preparation
Despite their ravenous appetite for flesh, it’s important to process your skull correctly before letting the beetles loose on it. My goal when cleaning any skull is to get it in and out of the colony quickly. This requires a little bit of skull preparation beforehand.
As mentioned, the skinned skull needs to spend a few days in the freezer prior to cleaning. Once it thaws, I remove the eyes, tongue, brain and any heavy muscle meat off the skull. The dermestid beetles will most certainly eat these items, but removing them reduces the cleaning time substantially.
I then use a few paper towels to dry off the processed skull. I want to make sure the skull isn’t wet or damp when I put it in with the bugs. If it’s a larger item, I’ll place a piece of cardboard under the skull to keep things cleaner and drier. I then cover the skull with bedding material (shredded up newspaper) to give the bugs a dark environment to work in.
Let it Sit for Awhile
With a hot colony, the skull cleaning process doesn’t take long. I’ve cleaned bobcat heads in four hours, coyote skulls in six and deer in about 30 hours. While it is tempting to pull the skull out of the colony when it’s done, it’s important to leave it in for a few more days.
Larvae will find their way in every nook and cranny in the skull, and leaving the cleaned skull in the colony will give them a chance to vacate. It’s also likely that the adult beetles have laid eggs on the skull, and I’d like to give them a chance to hatch and move off the head.
Once I’m confident that almost all the bugs are off the skull, I place it in a plastic bag and put it back in the freezer. This of course will kill any remaining bugs on the skull, so I make sure to get as many dermestids as I can off the item before placing it in the freezer.
Degreasing the Skull
Skulls rarely come out of the beetle process with an acceptable color for display. Most are dingy or gray and need to undergo a chemical process to lighten this darker coloration. This discoloration is usually from fluids such as grease or blood trapped in the pores of the bone. To remove these fluids, the skull must go through a degreasing. This process always occurs before the skull is whitened.
To draw these darker fluids out of the skull, many taxidermists and beetle culturists use a prolonged chemical soak in acetone. Through chemical dehydration, this helps lighten the darker spots and draw these fluids out of the bone. Another option is a lengthy soak in a commercial detergent such as Dawn dishwashing liquid. Termed the “poor man’s degreaser,” this process takes longer, but will eventually lighten the skull in preparation for whitening.
The Whitening Process
While some hunters and collectors like the natural bone color of recently cleaned skulls, most like to see their skulls whiter. This can be done with a whitening process after degreasing.
The No. 1 rule for whitening any skull is to stay away from bleach. Commercial bleach is very caustic and will eat away the bone of the skull, turning it chalky and brittle. Soaking in food grade or commercial grade hydrogen peroxide is the best way to whiten any skull.
I like to soak my skulls for several days in 11 to 17 percent hydrogen peroxide. Higher grade peroxide is available but pricey, and I’m looking to get things done cheaply. Once I’m satisfied with the soak, I place the skull in the sun to dry. The UV rays of the sun react with drying hydrogen peroxide to brighten the bone even further. This can also be achieved by placing the skull under UV lights to dry.
If you’re located near a beauty supply store, stop in and look for their clear hair developer, available in 20-, 30- and 40-grade concentrations. It’s priced at roughly $10 a gallon and contains a sufficient concentration of hydrogen peroxide to whiten skulls. Make sure you wear eye protection and gloves when dealing with the developer. This stuff will burn your skin if you come into direct contact with the liquid.
Won’t Harm the Living
The most common question I get is will these bugs chew me up and eat me in my sleep. These bugs are harmless, eat cold only meat and aren’t interested in anything alive. Dermestid beetles show up on a carcass about a week after the flies, to clean up the dried meat. During more than 22 years of culturing them, I have never been bitten or attacked. The entire skull cleaning process completely fascinates me. I enjoy cleaning skulls for others and explaining the entire process to anyone interested in learning about the bugs. While I spent my career studying fish and fisheries, my bug hobby has taught me to identify just about any skull in North America. If you’re interested in learning more, or cleaning your own skulls, check out my website, Dermestid Inc., or send me an email at timhovey4197@sbcglobal.net. I’ll be happy to answer any questions you might have.
