Bess Beetle (Odontotaenius disjunctus)

Can you believe that one out of every four animals on our planet is a beetle? If you look around under the
surface of the ground, in a garden, a rotten log or wood pile and you are likely to find a beetle. You may not have given these creatures much thought, but they do play an important role in the food web as scavengers and decomposers. Come try to find these interesting beetles as they make their debut in our “Bug House” at the entrance of the New England Farmyard.

Bess beetles are classified in the insect order called Coleoptera. This is the largest order of living things, with over 350,000 species. You are probably already familiar with a few members of this order. Ladybugs, scarabs and fireflies are all Coleoptera. They have hard, shell-like forewings, or elytra, from which the order gets its name. The word “koleos” means “sheath” in Greek, and “ptera” means “wing”. This unique structure is important to protect the beetle’s delicate hind wings and soft abdomen. The tough outer wings also protect the beetle as they squeeze through narrow places. This type of beetle is known by several different common names, such as Betsy beetle, Peg beetle, Patent leather beetle, Horned passalus beetle, and bessbug.


Adult beetles are about 1 1/2 inches long, shiny black with a series of grooves running the length of the forewings. They have a small horn between their eyes. Bess beetles have six legs and three body parts like other insects, but their thorax has two sections, which allows them to move more freely. These cool beetles have tiny gold-colored fringe on their legs and at the edges of their body. This fringe is thought to help keep the beetle clean. You can also notice the large mandibles, or mouth parts, which allow the beetles to chew through wood. Their feathery antennae are used to sense odors in the environment.


Inside hardwoods such as oak, elm and other deciduous trees that are well-decayed and fall apart easily.


Eastern and central United States and as far north as Canada.


Bess beetles chew wood, process it in their digestive systems, and a fungus grows on their feces. This fungus provides nourishment for the beetles.

Life Span: 

Larvae take more than a year to develop into adults, which can live up to 16 months.

Family Life: 

Bess beetles are social insects, living in colonies inside the tunnels they make in the wood. These tunnels are called galleries. Inside the galleries, beetles will mate, lay eggs, and raise their young. They stay in pairs, and carefully carry eggs in their mandibles. Larvae hatch from the eggs and look like white grubs. Both adults care for the young. When the larvae are ready, they become pupae (like cocoons) and are moved by their parents to a separate part of the gallery, where they rest until becoming adults. Bess beetles can produce sounds, which help them communicate in the darkness of their homes. Larvae can also make a different sound.


These insects are considered beneficial, important in recycling dead wood. They are fairly common, though more rare in the northern parts of their range.