You are probably thinking that selling rotten wood is like trying to sell the proverbial ice to Eskimos! But if you are into learning about Bess Beetles and want to keep them for study and pets, do read on. We have not lost our collective minds (hopefully). We are, in fact, offering you an opportunity to explore how, eventually, a piece of rotten wood begins to look less like rubbish and more like prime real estate. Enjoy!
Quick answer
For a first Bess Beetle colony, the complete habitat from Carolina Biological Supply Company is our practical starting point. It includes the cage, lid, beetles, wood, spray bottle and instructions. Buy the living pack only when suitable housing is already prepared. The separate rotting wood is a refill for a family that has eaten through the premises.
View the complete Bessbug Habitat at Carolina Biological (affiliate link)
Affiliate disclosure: The Carolina links in this guide are affiliate links. Clicking is free. If you make a purchase through one of these links, Bug Zoo® may earn a commission at no additional cost to you.
Reviewed by Carol Maier, B.Sc., professional entomologist and founder of the original Victoria Bug Zoo.
Why Bess might really be best
Bess Beetles, Bessbugs, Betsy beetles and patent leather beetles are all names used for members of the family Passalidae. The species described in Carolina's care guide is Odontotaenius disjunctus, the horned passalus. Adults are dark brown to black, approximately 1½ inches long and equipped with substantial mandibles designed for working through decaying wood.
Carol's field note: I have loved Bess Beetles since my first early encounter in Borneo. I kept them at the Bug Zoo too. They were big enough for visitors to see, gentle enough to hold and wonderfully easy to appreciate in the hand. However, as exhibit animals, they were hopeless little introverts. They stayed close to home, hid inside their log and devoted themselves to beetle family business. I respected that.
That homebody behavior is precisely what makes them interesting. Bess Beetles are among the comparatively small group of insects known for substantial parental care. A review in the Journal of Insect Science describes Passalidae living in family groups with male and female parents, eggs, larvae, pupae and young adults. Both parents participate in caring for the brood. The dads are not decorative.
A rotten log is an entire family enterprise
To a Bess Beetle, a decaying log is pantry, nursery, shelter, workshop and acoustic chamber. Adults tunnel through it, prepare food for their larvae and help the larvae construct the pupal cases needed for metamorphosis. The colony stays together inside the wood, where darkness and humidity suit them.
The digestive arrangement is magnificently unglamorous. Bess Beetles cannot obtain enough nutrition from wood by chewing it once. Adults consume fecal material containing the microflora that help break down wood fibres, then provide processed wood and microbe-rich material to their young. A beetle parent may never make a school lunch, but it has the digestive equivalent covered.
Carolina's Bess Beetle care guide also explains that adults and larvae stridulate. Adults rub specialized body surfaces together, while larvae use modified legs. The result is a repertoire of squeaks and chirps that may help colony members communicate inside a place where vision is of limited use.
Egg, larva, pupa, beetle
Bess Beetles undergo complete metamorphosis. Their life cycle moves through four distinct stages: egg, larva, pupa and adult. A larva does not resemble a miniature adult. It feeds, grows and eventually enters the pupal stage, where its body is reorganized into the familiar hard-shelled beetle.
According to Carolina, the larval journey to adulthood can take about a year. Adults may live for as long as 1½ years, and the complete life cycle can extend beyond two years. A University of Florida horned passalus species guide provides additional life-history information and identifies moist, decayed wood as the essential food and living material.
Captive reproduction is possible but uncommon. These beetles prefer the stability and space of a substantial decaying log, conditions that a small classroom habitat cannot perfectly reproduce. Even without a new generation, their feeding, tunnelling, communication and family behavior offer plenty to observe.
So what kind of rotten wood are we buying?
The separate Carolina refill listing does not identify the exact tree species. That is worth saying plainly. Carolina's habitat description refers to rotting hardwoods such as oak and elm, and its care guide recommends additional locally collected rotten hardwood or the prepared refill product.
The important word is rotting. Bess Beetles depend upon the fungi, bacteria and softened plant material associated with natural decay. They do not attack sound furniture, healthy trees or the structural beams holding up the science room. Their jaws and digestive partners are adapted to wood already well along in the process of returning to the forest floor.
Anyone gathering wood locally should choose naturally decaying hardwood from a clean and permitted location. Painted, treated or construction lumber has no place in the habitat. Purchased refill wood offers convenience and a defined classroom supply, although Carolina does not claim it comes from a particular hardwood species.
Three ways to assemble the beetle household
Our top pick: Complete Bessbug Habitat
This is the sensible choice for a teacher, homeschool family or first-time keeper starting from zero. Carolina says the habitat includes a cage with lid, Bess Beetles, wood, a spray bottle and instructions. It puts the animal, housing and essential decaying material into one coordinated purchase.
Best for: A new classroom or home colony that needs the complete setup.
View the complete Bessbug Habitat at Carolina Biological (affiliate link)
For an existing setup: 12 Living Bess Beetles
The living pack makes sense when suitable habitats are already waiting or when a teacher intends to divide beetles among several prepared enclosures. Carolina describes them as docile, slow-moving and suitable for study across grade levels. Living material has shipping restrictions and usually requires expedited delivery, so check the current availability and destination rules before ordering.
Best for: Established classrooms, labs or keepers with appropriate housing ready before arrival.
View 12 living Bess Beetles at Carolina Biological (affiliate link)
For hungry tenants: Rotting Wood Refill
This is the product that gave us the article and the laugh. Carolina supplies enough rotting wood to refill its Bessbug Habitat. It serves a legitimate purpose once the original wood has been consumed or broken down, especially when collecting suitable hardwood locally would be inconvenient or uncertain.
Best for: Replenishing an active Bess Beetle habitat without conducting a neighbourhood search for the perfect collapsing log.
View the rotting wood refill at Carolina Biological (affiliate link)
Basic Bess Beetle care
Prepare the habitat before the beetles arrive. Carolina recommends approximately 4 to 5 centimetres of moist potting soil or humus, leaf litter and damp decaying wood in a plastic or glass enclosure. Up to six beetles can be housed in a one-gallon terrarium. Keep the habitat humid rather than soggy, use indirect light and avoid overheating in direct sun.
A temperature around 20 to 22°C (68 to 72°F) suits them, and supplemental heat is generally unnecessary. Mist as needed and adjust ventilation if mold becomes excessive. Resist the urge to scrub the habitat into sterility. The wood, soil, microorganisms and beetle droppings form part of the digestive system that keeps the colony functioning.
Handle them gently and keep them off loose-knit clothing. Their hooked feet can cling firmly enough that removing them from a sweater may injure the beetle. Wash hands before and after working with any living organism or habitat material.
Frequently asked questions
Are Bess Beetles dangerous?
No. Carolina describes them as harmless and docile. Their mandibles are adapted to chewing rotten wood. A beetle may manage a mild pinch, but it is not built to attack people.
Why do Bess Beetles squeak?
They create sound by stridulation. Adults and larvae use different body structures to make their noises, which appear to play a role in communication among family members inside the log.
Do both parents care for the young?
Yes. Bess Beetles are known for biparental care. Male and female adults remain in the family group, prepare food and assist the developing larvae.
Will Bess Beetles eat my house?
No. They depend upon the fungi and bacteria in decaying or damaged wood and do not attack healthy, intact lumber. Your furniture is safe unless it has already become a forest floor.
Can I collect my own rotten wood?
Carolina's care guidance allows locally collected rotten hardwood. Choose naturally decayed material from a clean, permitted source and avoid painted, treated or construction wood. The commercial refill is the convenient option when suitable material is unavailable.
Final thoughts
If you can sell rotten wood, you can sell almost anything. In this case, the sale is defensible. A suitable log supports the beetles' food, microbes, tunnels, communication and extraordinary family life.
The complete habitat is our best starting point because it brings the essential pieces together. Existing keepers can choose the living pack or replenish the family pantry with more wood. Step right up. The log looks terrible. The tenants are magnificent.
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