Back before our floods last month, I wrote a column about mushrooms and their ecological role as decomposers. I mentioned their importance in keeping us from getting up to our eyebrows in organic matter, but I only told a small part of the decomposition story.

The root-like hyphal network of a fungus does break down dead things with chemical processes, but there are many other organisms that decompose by mechanical means. Termites and carpenter ants, for example, chew wood into oblivion--much to the chagrin of owners of old farmhouses like ours at Hilton Pond. Fly larvae burrow through road-killed animals and convert them into piles of fur and bone, and scarab beetles were venerated in ancient Egypt for their proclivity at turning dung into topsoil.

Recently I was reminded of the importance of decomposers as I looked under firewood for food for a captive woodpecker. Even beneath newly-split chunks of wood I saw millipedes, roaches, ants, worms, termites, or an occasional toad, but under seasoned and partly-rotten logs there were always two or more large black beetles.

The insects I found, sometimes called Patent-leather Beetles because of their shiny black appearance, were about 2 inches long and moved slowly when exposed to light. Invariably they were crawling through what looked like piles of sawdust but actually were sizable accumulations of beetle droppings mixed with partially-decayed wood.

Some of the stout-bodied beetles were lodged in cylindrical tunnels scarcely their own width, an indication they had eaten their way into dead ends. Disturbed but unable to turn around, some of them backed out of the half-inch tubes, dropped into the sawdust layer, and burrowed out of sight.

Only three species of Patent-leather Beetles--known also as Horned Beetles, Bessbugs, or Bess Beetles--occur in the United States. Two are restricted to south Texas, and there is only one eastern species, so I was sure what I had found was a horned type known as Odontotaenius (formerly Popilius) disjunctus. The species name--disjunctus--accurately describes the beetle's profile: its thrice-segmented body appears divided into two distinct parts connected by a very thin "waist."

Bessbugs are classified further into beetle Family Passalidae, in which there are 300 species worldwide. Our local Bess Beetle is one of few found outside the tropics, and its range is limited to the milder southeastern and mid-Atlantic states.

All Bess Beetles are rather social, living colonially in galleries within or under decaying logs and stumps of oak, hickory, and Sweetgum. As I picked up one of these insects, it made a faint squeaking that resembled the sound you hear when chewing on a deflated balloon or rubber band. An apparent distress call made by disturbed beetles, the squeaks may allow communications among colony members. The adult makes sound by rubbing the rough underside of its wing against a similarly rough abdominal surface in a process called "stridulation." Larvae--large, fat, white grubs with light brown heads--stridulate by scratching legs against the rear portions of their soft abdomens. What all these adult and immature insects might be saying to each other is anybody's guess, but it's probably worth a couple or three doctoral research projects to try to find out.

Unlike many insects, Bess Beetles tend their young. Adults prepare decaying wood for the larvae by chewing and mixing it with salivary secretions. Within the wood are many microorganisms--flagellates, ciliates, and bacteria--that also are ingested by the adults, and this mixture of chewed wood, saliva, and microbes is fed to the larval stages. One of the most remarkable aspects of the Bessbug social system is that adult males help care for the young, a phenomenon almost unheard of among insects. Only in termites and one other beetle family do males play a role in feeding, protecting, and raising their offspring.

Larvae develop for up to a year and then change drastically, turning first into a ghost-like pupal stage that resembles a butterfly chrysalis. After developing and darkening for a few months, the pupal exoskeleton opens to yield an adult Bess Beetle that goes off to find a mate. In one of her under-log galleries the fertilized female lays eggs that eventually hatch into tiny larvae, and the cycle starts anew. Although most people associate "complete" metamorphosis only with butterflies and moths, the life cycle of beetles also includes four stages: egg, larva, pupa, adult.

For many of the 750,000 beetle species--and there are more beetles than any other kinds of insects--the entire life cycle is spent in darkness inside standing and fallen dead timber. Thus, it is not unusual to find other beetle species under rotting logs, but few of them can match the Bessbug in sociality, size, or longevity.

Since Bess Beetles have relatively long life cycles (most insects die within a few days after becoming adults), it is possible to find them under decaying wood at nearly any season of the year. Often in winter, as I bring in logs for one of my four fireplaces, I must pry up firewood frozen to the ground, and at the bottom of the woodpile there are usually several adult Bessbugs in a semi-comatose state. Many overwintering insects hibernate by replacing cellular water with glycerin, which serves as antifreeze. This new body fluid keeps the Bess Beetle sluggish and unable to help with decomposition, but it prevents him from freezing solid and perishing during cold winter months.

Despite the ability to chew through solid oak, even active Bessbugs are not known to bite. Being large, slow-moving, and non-aggressive, they are excellent demonstration specimens to use in teaching children--or squeamish adults--about insects. They can be maintained in a container filled with partially decayed wood, but should be returned to a more natural location when they have served their educational purposes.

My only cautionary remark is that beetle fanciers need to roll each log back into place as they look for or release their specimens. Thoughtless natural history buffs--especially some snake hunters I have known--are bad about leaving logs and stones overturned, and all collectors should be careful not to destroy microhabitats that may have taken years to develop.

If Bessbugs are to work effectively as decomposers, we would do well not to disturb them or their logs as they go about the important business of "making molehills out of mountains."