Hardwood Stump Borer Beetle

The durable Hardwood Stump Borer Beetle male has quite a set of jaws on it, but its the larvae that do the most damage to trees.

Large thick pincers (jaws) on the males are quite intimidating. Fine hairs grow on the inner edge of each pincer. The robust size of the beetle is actually a little surprising, too. They have larger, thicker mouth parts than females. Males also have a longer, more slender body, while females are rounder. All Hardwood Stump Beetles are a dark brown, almost black with a smooth, matte finish. They have a boxy thorax with fine teeth on the outer edges. Adults feed on ants and other insects. Both genders are capable of inflicting a painful bite if disturbed, but they do not go out of their way to attack.

The larvae of this species is usually found inside tree stumps, decks and other wooden structures. Sometimes it is found in living trees that have not been cut down. The eat away at the wood as they develop. They leave holes in the wood as they exit the tree. It can take 3 to 4 years for a grub to fully mature. Most types of hardwood trees can serve as hosts for this type of beetle like willow, maple, oak, elm, and pecan trees. In large numbers, Hardwood Stump Borers can negatively impact furniture, flooring, and other wood-based industries.

Taxonomic Hierarchy

Kingdom: Animalia

Phylum: Arthropoda

Class: Insecta

Order: Coleoptera

Family: Cerambycidae

Genus: Mallodon

Species: dasytomus

Identifying Information

Scientific Name: Mallodon dasytomus

Other Name(s): Tooth-Necked Longhorn Beetle

Category: Beetle

Size (Adult; Length): 35mm to 50mm (1.37in to 1.95in)

Colors: black; brown

Descriptors: jaws, spikes, flying

Territorial Map

Alaska

Hawaii

Prince Edward Is.

Contiguous United States shape map layer graphic

Territorial Reach (A-to-Z)

Newfoundland and Labrador

Mexico

Note: An insect's reach is not limited by lines drawn on a map and therefore species may appear in areas, regions and/or states beyond those listed above as they are driven by environmental factors (such as climate change), available food supplies and mating patterns. Grayed-out selections indicate that the subject in question has not been reported in that particular territory. U.S. states and Canadian provinces / territories are clickable to their respective bug listings.

Beetle Anatomy

Graphic showing basic anatomy of a common North American Beetle insect

Antennae: Beetles have a pair of antennae on the head used as sensors.

Head: The head is home to the insect's eyes, antennae, and mandibles (jaws).

Thorax: Holds the three pairs of legs as well as vital internal organs.

Elytron: One of two wing cases on a Beetle that protects its wings (plural: elytra).

Wings: Appendages used for flying and kept under the elytra until needed.

Abdomen: Houses organs related to circulation, reproduction, and excretion.

Legs: Beetles have three pairs of legs located at the thorax, numbering six legs in all.

Hardwood Stump Borer Beetle (Mallodon dasytomus)

The durable Hardwood Stump Borer Beetle male has quite a set of jaws on it, but its the larvae that do the most damage to trees.