Home / Longhorn Beetles (Cerambycidae) / Old House Borer Beetle (Hylotrupes bajulus)

Old House Borer Beetle (Hylotrupes bajulus)

The old house borer beetle is one of the most dangerous wood-destroying insects, second only to the termite. This beetle prefers newer wood than old, contrary to its name, possibly due to the higher resin content.

Famous Swedish botanist Carl Linnaeus identified these beetles in 1758, which is the sole member of its genus.

Old House Borer Beetle

Scientific Classification

  • Family: Cerambycidae
  • Genus: Hylotrupes
  • Scientific name: Hylotrupes bajulus

Physical Description and Identification

Adult 

Size: 8–20 mm (0.31–0.79 in)

Color: It appears black or brown, covered with gray fuzz.

Other Characteristic Features: Their bodies are flattened with two prominent knobs on the prothorax. A shiny ridge is present in the middle of the thorax, with two more on its side, making them look like eyes. The elytra have two white spots forming irregular bands in its center.

Hylotrupes bajulus
House Longhorn Beetle

Larva

They are cream-colored and 1.25 inches long when fully mature. Tiny eyespots are present on both sides of their heads. Upon hatching, they proceed to bore into the wood, which also acts as their food source.

They can stay up to 2-5 years this way, depending on available food, humidity, and temperature.

Old House Borer Beetle Larva

Pupa

The pupation takes place just below the surface of the wood.

Old House Borer Beetle Pupa

Egg

The adults lay eggs in the cracks of the wood of the host plants.

Quick facts

Other NamesHouse longhorn beetle, European house borer beetle
Lifespan2-5 years on average, sometimes even reaching 10 years
DistributionAsia, Australia, the Americas, North Africa, and most of the Mediterranean and Europe
HabitatHigh moisture areas inside households like basements, damp crawl spaces, and storage areas
Seasons activeJune- September
Host plantsFir, spruce, pines, and other coniferous trees
Diet of adults and larvaeSoftwood
Old House Borer Beetle Pupa

Identifying the Damage Caused by Them

When the larva or adults bore through wood, they leave sawdust-like waste near the holes. If these forms of debris keep reappearing, it means an infestation has taken place. Sometimes even the exit holes are big enough to identify the damage.

Did You Know

  • When they chew through wood, the larva makes a raspy or clicking sound. Usually, humans can’t hear these sounds, but they become audible to the human ear under high moisture conditions.
European House Borer
Old House Borer Beetle Picture

Image Source: cdn.branchcms.com, live.staticflickr.com, extension.umd.edu, nzffa.org.nz, biolib.cz, bugwoodcloud.org, agric.wa.gov.au, proactivepestga.com

The old house borer beetle is one of the most dangerous wood-destroying insects, second only to the termite. This beetle prefers newer wood than old, contrary to its name, possibly due to the higher resin content.

Famous Swedish botanist Carl Linnaeus identified these beetles in 1758, which is the sole member of its genus.

Old House Borer Beetle

Physical Description and Identification

Adult 

Size: 8–20 mm (0.31–0.79 in)

Color: It appears black or brown, covered with gray fuzz.

Other Characteristic Features: Their bodies are flattened with two prominent knobs on the prothorax. A shiny ridge is present in the middle of the thorax, with two more on its side, making them look like eyes. The elytra have two white spots forming irregular bands in its center.

Hylotrupes bajulus
House Longhorn Beetle

Larva

They are cream-colored and 1.25 inches long when fully mature. Tiny eyespots are present on both sides of their heads. Upon hatching, they proceed to bore into the wood, which also acts as their food source.

They can stay up to 2-5 years this way, depending on available food, humidity, and temperature.

Old House Borer Beetle Larva

Pupa

The pupation takes place just below the surface of the wood.

Old House Borer Beetle Pupa

Egg

The adults lay eggs in the cracks of the wood of the host plants.

Quick facts

Other NamesHouse longhorn beetle, European house borer beetle
Lifespan2-5 years on average, sometimes even reaching 10 years
DistributionAsia, Australia, the Americas, North Africa, and most of the Mediterranean and Europe
HabitatHigh moisture areas inside households like basements, damp crawl spaces, and storage areas
Seasons activeJune- September
Host plantsFir, spruce, pines, and other coniferous trees
Diet of adults and larvaeSoftwood
Old House Borer Beetle Pupa

Identifying the Damage Caused by Them

When the larva or adults bore through wood, they leave sawdust-like waste near the holes. If these forms of debris keep reappearing, it means an infestation has taken place. Sometimes even the exit holes are big enough to identify the damage.

Did You Know

  • When they chew through wood, the larva makes a raspy or clicking sound. Usually, humans can’t hear these sounds, but they become audible to the human ear under high moisture conditions.
European House Borer
Old House Borer Beetle Picture

Image Source: cdn.branchcms.com, live.staticflickr.com, extension.umd.edu, nzffa.org.nz, biolib.cz, bugwoodcloud.org, agric.wa.gov.au, proactivepestga.com

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