Home / Longhorn Beetles (Cerambycidae) / Brown Prionid Beetle (Orthosoma brunneum)

Brown Prionid Beetle (Orthosoma brunneum)

The brown prionid beetle is a longhorn beetle found in the US. It is the only known species in its genus Orthosoma.

Brown Prionid Beetle

Scientific Classification

  • Family: Cerambycidae
  • Genus: Orthosoma
  • Scientific name: Orthosoma brunneum

Physical Description and Identification

Adult

Size: 25-50 mm

Color: They have a characteristic brown body, resulting in their name.

Other Characteristic Features: Like most other long-horned beetles, the brown prionid has a long antenna, exceeding its body length.

Orthosoma brunneum

Larva

The larva is white with brown spots on each segment and a set of brown mandibles. It eats decaying wood with fungi in it, which helps it digest the cellulose in wood. They do so for 3-5 years.

Brown Prionid Beetle Larva

Pupa

Pupation takes place in a soil chamber near the roots of the host plant.

Egg

The eggs are laid in wood (not decayed).

Brown Prionid Beetle Eggs

Quick facts

LifespanNot recorded
DistributionCommon in the United States
HabitatMoist decaying wood
PredatorsBlind Click Beetle
Seasons activeDuring the warmer months of the year
Host plantsFir, serviceberry, sumac, pine, oak, willow, poplar, and stone fruit
Diet of adultsSap and rotting fruits

Identifying the damage caused by them

The damage caused by this beetle is limited to the roots of trees, though it is minor most of the time.

Did you know

  • When frightened, this beetle generates a squeaking sound by rubbing its back legs against its wings.
Longhorned Beetle Brown Prionid
Brown Prionid Beetle Range

Image Source: svtweb.org, amazonaws.com, bugguide.net

The brown prionid beetle is a longhorn beetle found in the US. It is the only known species in its genus Orthosoma.

Brown Prionid Beetle

Physical Description and Identification

Adult

Size: 25-50 mm

Color: They have a characteristic brown body, resulting in their name.

Other Characteristic Features: Like most other long-horned beetles, the brown prionid has a long antenna, exceeding its body length.

Orthosoma brunneum

Larva

The larva is white with brown spots on each segment and a set of brown mandibles. It eats decaying wood with fungi in it, which helps it digest the cellulose in wood. They do so for 3-5 years.

Brown Prionid Beetle Larva

Pupa

Pupation takes place in a soil chamber near the roots of the host plant.

Egg

The eggs are laid in wood (not decayed).

Brown Prionid Beetle Eggs

Quick facts

LifespanNot recorded
DistributionCommon in the United States
HabitatMoist decaying wood
PredatorsBlind Click Beetle
Seasons activeDuring the warmer months of the year
Host plantsFir, serviceberry, sumac, pine, oak, willow, poplar, and stone fruit
Diet of adultsSap and rotting fruits

Identifying the damage caused by them

The damage caused by this beetle is limited to the roots of trees, though it is minor most of the time.

Did you know

  • When frightened, this beetle generates a squeaking sound by rubbing its back legs against its wings.
Longhorned Beetle Brown Prionid
Brown Prionid Beetle Range

Image Source: svtweb.org, amazonaws.com, bugguide.net

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