What Does Bess Beetles Eat: A Friendly Guide to Their Diet

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Bess beetles, also known as betsy beetles or patent leather beetles, are fascinating creatures that play an essential role in recycling rotting wood.

As you begin to explore the world of bess beetles, one of the first things you might wonder is, “What do bess beetles eat?”

These beetles, along with their larvae, primarily consume decaying wood. Adults prepare the wood for their offspring by chewing on it first, breaking it down into manageable pieces for the larvae to eat.

What Does Bess Beetles Eat
Bess Beetles

This process not only nourishes the beetles but also helps in breaking down dead tree logs, contributing to the nutrient cycle in forests.

So next time you encounter a bess beetle, you can appreciate its unique diet and the vital role it plays in our ecosystem.

About Bess Beetles

Bess beetles, also known as Odontotaenius disjunctus, belong to the family Passalidae within the Coleoptera order of insects.

Bess Beetle

They are quite distinct, as their black, glossy appearance and size, which can be up to 1½ inches long, make them easily recognizable.

They are sometimes confused with cockroaches due to their long, black bodies.

These unique beetles are commonly found throughout the eastern United States.

They play an essential role in the ecosystem by helping recycle decaying wood.

Both adults and larvae live inside rotting logs and contribute to breaking down the wood material.

They are harmless creatures and cannot even bite humans.

Here are some of their characteristics:

  • Glossy black color
  • Size up to 1½ inches long
  • Deep grooves on hardened forewings
  • Small horn-like structure on the head
  • Strong jaws

Many times, bess beetles can be confused with cockroaches due to their size and black color.

Now let’s explore their diet. Bess beetles primarily feed on decaying wood. In fact, finding them in the wild often involves looking for chewed wood or frass.

When you discover them, it’s crucial to collect the wood they inhabit along with the surrounding decaying materials to provide proper nourishment.

Bess Beetle

Bess Beetle Habitats

Bess beetles, also known as betsy beetles or horned passalus, are found in various habitats across North America, particularly in the tropical regions and parts of the US such as Florida.

These beetles usually make their homes in rotting logs and tree stumps where they feed on decaying wood.

In these habitats, they play an essential role in breaking down dead plant material and recycling nutrients back into the ecosystem.

Some notable features of their habitats:

  • Bess beetles in both tropical and temperate regions of North America
  • Presence of these beetles in regions like Florida, where they are quite common
  • Habitats consisting mainly of rotting logs and tree stumps

When maintaining a habitat for bess beetles in captivity, be sure to provide decaying wood and surrounding chewed wood or frass for their enclosure.

You may need to add more decaying wood as they eat through their original source.

What Does Bess Beetles Eat?

Bess beetles primarily eat decaying wood. Their diet consists of consuming the wood they reside in, making their habitat their source of nutrition.

You may find these beetles in rotting logs and wood piles, where they play a vital role in breaking down decomposed plant material.

When setting up an enclosure for them, ensure you collect adequate amounts of rotting wood for their feeding and shelter needs.

Bess Beetle

As they continue to consume the wood, you’ll need to replenish their food source by adding more decaying logs.

Keep in mind that bess beetles are not the only creatures to benefit from consuming decaying wood. Various other insects and microorganisms also contribute to the breakdown of plant material in ecosystems.

Reproduction and Life Cycle

Bess beetles go through a life cycle which involves four primary stages: eggs, larvae, pupae, and adults. Let’s dive into a quick overview of each stage to understand the reproductive cycle better.

Female bess beetles lay tiny eggs in decaying logs. These eggs then hatch into small, pale larvae, which feed on decomposing wood. As these larvae grow, they shed their exoskeletons multiple times in a process called molting.

The next stage is the pupal phase, where the larvae transform into adult beetles. During this phase, they remain motionless and undergo complete metamorphosis, reshaping their body structure and developing wings.

Finally, the adult bess beetle emerges from the pupal case, ready to contribute to the colony’s survival. Adults are primarily responsible for gathering food, maintaining the nest, and caring for the eggs and young larvae.

Physical Attributes

One of the most notable characteristics of bess beetles is their size. Adults can reach up to 1 ½ inches (4 cm) in length, making them quite large compared to many other beetle species.

Their body consists of three main parts: the head, the thorax, and the abdomen.

This image has an empty alt attribute; its file name is bess_beetle_crystal.jpg

Bess Beetle

On their head, bess beetles have elongated, curved mandibles. These mandibles are primarily used for chewing on rotting wood, which is their main food source.

They also have antennae, which they use for sensing their environment and communication with other beetles.

Covering the thorax and abdomen, you will find the elytra. These are modified, hardened forewings that cover and protect the delicate hindwings underneath.

Bess beetles can use their wings to fly.

The elytra also provide protection for the beetle’s soft abdomen. Bess beetles showcase a shiny, black or dark reddish brown exterior.

Some unique features of bess beetles include:

  • Stridulation: Bess beetles produce sound as a defense mechanism, achieved by rubbing specific body parts together. This helps to warn other beetles of danger (source).
  • Social behavior: Unlike many other beetle species, bess beetles are known for their social interactions and communal living habits, often residing together in rotting logs.

You will likely find bess beetles living in temperate regions like Eastern U.S. and some in Japan. They aid in the recycling of decaying wood and contribute to the overall health of the ecosystems they inhabit.

Behavior of Bess Beetles

Bess beetles are known for their interesting behaviors. One key aspect of their behavior is their diet.

They primarily feed on decaying wood, which they help break down further. Both adult bess beetles and their larvae contribute to this decomposition process.

In terms of social behavior, bess beetles are considered subsocial insects. Their subsocial nature means they display parental care and colony-like behavior.

Bess Beetle

This includes taking care of their larvae, with adults often preparing the wood for them by chewing on it first to make it easier for the larvae to consume as mentioned in Nebraska’s Science Literacy and Outreach.

When it comes to communication, bess beetles produce sounds through a process called stridulation. This involves rubbing certain body parts together to create unique low squeaking sounds. These sounds can be heard when bess beetles are disturbed or in certain social interactions.

Bess Beetles and Mites

Bess beetles, also known as bessbugs or patent leather beetles, are large insects that play a crucial role in recycling rotting wood.

They mainly consume decaying wood for food and shelter. Did you know that both adults and their larvae live in rotting wood? Adult bess beetles even prepare the wood for their larvae by chewing on it first.

During your observations of bess beetles, you might wonder if mites play any role in their lives. To investigate this, you could design an experiment and create a hypothesis.

For example, your hypothesis might be that mites have a symbiotic relationship with bess beetles, benefiting from the beetle’s habitat without harming it. To test this hypothesis, you could observe the beetles with and without mites in their environment, and note any effects on their behavior or health.

Bess Beetle

Here are a few key features of bess beetles:

  • Adults are about 1½ inches (4 cm) long
  • They have a glossy black appearance
  • Their hardened forewings have deep grooves
  • A small “horn” is found on top of their head, curving forward

As you conduct your experiment, be sure to document your observations, results, and any conclusions that you can draw from your findings. Remember to stay open-minded and avoid making exaggerated or false claims.

In the end, your research on bess beetles and their interaction with mites might contribute valuable knowledge of these fascinating insects and their role in our ecosystem. So, enjoy exploring the entomological world of bess beetles and mites!

Bess Beetles as Classroom Pets

Bess beetles, also known as betsy beetles, can make interesting classroom pets. They are easy to care for, and their size, approximately 1½ inches long, makes them appealing to students.

These beetles are primarily wood eaters. In their natural habitat, they live in rotting wood, like logs and stumps. To mimic this environment in your classroom, provide them with:

  • A small terrarium or plastic container with a lid
  • A ventilated lid for air circulation
  • Pieces of rotting wood for food and shelter
  • A shallow water dish for hydration

ace for your students while providing a home for these fascinating beetles.

Just remember to keep their habitat clean, provide fresh rotting wood, and ensure their water dish is always filled. With a little effort, bess beetles can become a unique and educational addition to your classroom.

Bess Beetle

Bess Beetles in the Ecosystem

Bess beetles have a crucial role in the ecosystem. They serve as decomposers, feeding on decaying wood. Their presence facilitates the breakdown of dead trees, contributing to a healthier environment.

As an example, the horned passalus beetle (Odontotaenius disjunctus) is a type of bess beetle commonly found in the eastern U.S. They live in rotting logs and help recycle wood back into soil nutrients.

During this process, these beetles not only consume decaying wood but also prepare it for their larval stage, further aiding decomposition.

Their importance in the ecosystem can’t be underestimated:

  • They promote the natural recycling of nutrients found in decaying wood.
  • By breaking down dead trees, they help maintain the forest’s overall health.
  • Habitat creation: decayed logs provide shelter for other insects and small animals.

In summary, bess beetles are an essential part of the ecosystem, contributing to the natural processes that maintain a balanced environment. Just like you, they play their part in keeping the Earth healthy and thriving.


In conclusion, bess beetles, or Odontotaenius disjunctus, are remarkable insects with a unique diet of decaying wood, playing a vital role in our ecosystems.

They are easily recognizable by their glossy black appearance and size, and their habitats are primarily in rotting logs across North America.

Understanding their diet, life cycle, and behavior, including their social nature and stridulation, enhances our appreciation of these creatures.

Their role as decomposers highlights their importance in nutrient recycling, making them an intriguing subject for study and even as classroom pets.

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about Bess beetles. Scroll down to have a look at some of them.

Letter 1 – Bess Beetle with Mites

Passalidae with a hip hairdo
Location: Arlington, Texas, heavily wooded area
March 25, 2011 7:23 pm
I used your website to id this as a bess bug, but I’m wondering what the little red bumps are around its horn? Parasites? They didn’t appear to be moving, but it was running about so it was hard to tell.
Signature: Moo

Bess Beetle with Mites

Hi Moo,
We get very excited when we learn that submitters to our site have been able to make a difficult identification using our site.  Those are Mites on the Bess Beetle.  We are uncertain if they are parasitic or if they are using the Bess Beetle for transportation purposes, an action known as phoresy. 

If we knew that Bess Beetles flew, we would suspect Phoretic Mites, but it appears the elytra of the Bess Beetle might be fused.  This needs research.  According to Fossweb Teachers Bess Beetle page: They all have hard, shell-like forewings, or elytra, from which their name is derived. In Greek, koleos means “sheath,”and ptera means “wing.”

This unique structure functions as a tough protector of the beetle’s delicate hind wings and soft abdomen. When the beetle decides to fly, the hind wings unfold and do their job. At rest they tuck themselves back under the hard elytra.

The site also discusses the Mites thus:  “Mites. Eating fungus that grows on decaying wood, providing care for larvae, communicating through sounds—these are all fascinating features of bess beetles. But they have another interesting feature—they have coevolved with at least one kind of mite. Mites are commonly found hitchhiking on the body of the bess beetle.

Some of these mites are found only on bess beetles, suggesting a relationship that has evolved along with the organisms. It’s not clear that the beetles benefit from the mite, but because of their exoskeleton, they aren’t harmed in any way. It may be that the mites live on secretions given off by the beetle, or they may just find protection from the beetle while they share the decaying wood.

The mites are not known to damage the beetles, don’t bite or harm students, and do not leave the classroom habitat basins. Should mites get on a student’s hand, they are easily brushed off.”

Nice! I’m completely in love with these beetles, so glad to know it wasn’t being eaten or anything. 🙂

Letter 2 – Bess Beetle from Australia with Bronchial Beetle link

Is this a Shield Bug?
January 26, 2010
Image 1.I first thought this was a Shield Bug, but am not so sure especially the hind legs?
Image2. Large 2inch beetle?
Image3. What type of Assasin bug could this be?
Many Thanks
Jeff Keyes
Jeff @sportsmancreek.org
Grafton New South Wales Australia

Bess Beetle

Hi Jeff,
We have already chastised you for sending us three images and a list instead of a more descriptive letter, but your submission has provided us with one of our more entertaining links in a long time.

First we will identify your beetle, which is a Passalid Beetle.  In North America, they are also called Patent Leather Beetles or Bess Beetles, and they live in colonies in rotted wood where mated pairs care for and communicate with their young. 

According to the Rainforest Insects of Australia website:  “Passalid beetles are found particularly in wet tropical and subtropical forests where they feed on decaying wood.

Many are large and shiny black with ‘waists’ between front and back sections.
They are of particular interest because they live in semi-social family groups, with parents caring for and feeding their young.

The young larvae lets its parents know where it is by rubbing hind and mid legs together to produce a sound.
The adults (which rub hind wings against abdomens in reply) then chew up wood for the larva to feed on.
Their presence in a log can often be detected by the presence of large piles of sawdust collecting beneath the log.”

The Csiro entomology site of Australian insects lists two species, Pharochilus rugiceps, the Common Passalid Beetle, and the Giant Passalid Beetle, Mastachilus quaestionis.  Alas, we are unable to tell you which species you have submitted.

And now for that interesting link we promised.  Upon trying to research a species name for an Australian Passalid Beetle, we located a page with an Xray of a human chest and the title:  “Bronchial beetle  D J Serisier, M Singh, S D Bowler + Author Affiliations  Department of Respiratory Medicine, Mater Adult Hospital, South Brisbane, Queensland 4101, Australia” 

The accompanying text reads: A 74 year old man presented to hospital after waking with chest discomfort and haemoptysis, and left lung collapse was seen on the chest radiograph (fig 1). Twelve years earlier he had undergone laryngectomy and postoperative radiotherapy for laryngeal squamous cell carcinoma and had a permanent stoma.

He had a smoking history of 35 pack years. New endobronchial malignancy was suspected, but bronchoscopy revealed the cause of his left sided airway obstruction to be a 4 cm beetle (fig 2)! Chest radiographs taken after removal of the beetle demonstrated lung re-expansion. The beetle was later identified as a Passalid beetle, species aulacocyclus, a species that resides in rotting logs.”

After posting an image of the beetle, the story continues with: During the day preceding his symptoms the patient had been working in his yard, chain sawing trees. It is likely that the beetle became attached to his clothing and that night crawled through his open tracheostomy while he was sleeping, becoming wedged in his left main bronchus.

He subsequently awoke with the sensation of ‘something scratching in my chest’, a description only fully appreciated in retrospect.  …  Our patient has been advised to cover his stoma while sleeping. Although further unexpected Passalid beetle inhalation is highly unlikely, there are many other ‘creepy-crawlies’ to beware in subtropical Australia!”

Though we cannot positively identify which species of Passalid Beetle you have submitted, we have been highly entertained.  We also followed up on the species mentioned in the Bronchial Beetle story, and found and Oz Insect page on Aulacocyclus edentulus.

Dear Daniel.
Firstly, chastisement accepted and respected! I am amazed that my email got through as I live in a fairly remote area and my laptop is powered by the sun. I have a wildlife refuge and am putting together a composite list of all creatures great and small.

Please check out www.sportsmancreek.org and the corresponding blog site http:// sportsmancreek.wordpress.com/ which I update as much as possible. The internet is such a powerful tool and your found link to my beetle is totally amazing!

And yes, I have heard them communicating under bark of Ironbark trees. Thanks, again for your interest and prompt response.
Kind Regards
Jeff Keyes.

Hi again Jeff,
Thanks so much for providing information on your conservation website.  It has long been a fantasy here at What’s That Bug? to apply for a grant to go to Australia since there are such amazing contributions to the website from down under, and there are also a wealth of Australian websites devoted to insects.

Your own project at Sportsman Creek is a noble effort and we wish you all the luck with the project.  Here in Los Angeles, our editorial staff is fighting its own battle to save the highly endangered and fragile California Black Walnut Woodland ecosystem, and our biggest problem is that the few remaining areas of this natural habitat are in highly desirable real estate areas, and speculation developers tend to have greater capital than preservationists do.  We want sun powered laptops.

Dear Daniel.
I appreciate the encouraging words. It, seems developers worldwide do have the “whip-hand”, for the present. I have over 40 logging trucks per day trundle their booty to the mills passing the front gate! However, we must persevere in seeking answers to long asked questions. If you guys make to Australia, there is an Open Invitation to Sportsman Creek wildlife refuge.
Kind Regards

Letter 3 – Bess Beetle from Thailand

Dear Bugman…
I found this big guy (around 4cm long) in rotten wood, in tropical forest (around 1000m elev, Thailand)… Is it a Ceruchus? Thank you in advance for your help and website, great idea!

Hi Gilles,
This looks to us to be a species of Bess Beetle in the family Passalidae. Bess Beetles or Bessbugs are interesing beetles. They have a semi-social structure with adults and larvae living together in rotten wood. The adults feed the larvae pre-chewed wood. Both adults and larvae are capable of stridulation, or making sounds.

Letter 4 – Bess Beetle or Horned Passalus

What is this guy?
I am resending this message, being that the original was sent during metamorphosis. Since my original message, he chewed out of the bug home the teacher had for him in the classroom, the kids had to do a search for him and found and released him.

Hi, My son found this guy on our wood pile (his class is studying bugs this week and the kids have been asked to bring in some critters!). He makes a funny sort of sound like huu huu.

We live in the western part of Virginia (Shenandoah valley).
If I could guess – Is it some kind of ground or stag beetle? The body to me looks similar to those but haven’t found any pics of either with that little horn on his head.
Your site is very cool! Going to recommend it to his teacher to look at with the kids!!
Just read your site is “undergoing metamorphosis” so I hope we can hear back before “bug week” at school is out!
Mary Jo and Andrew
Staunton, VA

Bess Beetle
Bess Beetle

Hi Mary Jo and Andrew,
We are very happy you decided to resend your letter because there have been some taxonomic changes since we first posted images of Bess Beetles on our site. Bess Beetles, also known as Bess Bug, Betsy Beetle or Bug, Patent Leather Beetle, Peg Beetle and Horned Passalus, are now reclassified as Odontotaenius disjunctus. According to BugGuide, other names have included: “Scarabaeus interruptus Linnaeus 1764
Passalus cornutus Fabricius 1801
Passalus distinctus Weber 1801
Passalus bos Kuwert 1891
Popilius disjunctus in much of the older literature ” Bess Beetles are quite interesting as they live in communities consisting of adults and grubs. BugGuide also indicates: “Lifestyle of this family is unique for beetles: live in small colonies where larvae are cared for by adults of both sexes. Long life cycle, apparently more than one year.

Larvae eat a rotting wood prechewed by adults. (Some references state larvae eat feces of adults as well.) Larvae and adults also cannibalize injured larvae. … Both adults and larvae make noises by stridulation, and this is said to serve as communication between them.

Adults also stridulate when picked up, and especially, blown on. Stridulation mechanism of adults by rubbing abdomen against the wings. Larvae stridulate with reduced third pair of legs–these scratch against other legs. ” Bess Beetles are in the Family Passalidae which is part of the superfamily Scarabaeoidea that incluces Scarab, Stag and Bess Beetles.


  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

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  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

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1 Comment. Leave new

  • We brought home two Bess Beetles from school. One of them died and when we picked it up a two centimeter worm (parasites) crawled out. How do we dispose of it?


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