Bug FAQRed Flat Bark Beetle
Cucujus clavipes · Order: Coleoptera · Family: Cucujidae
Red Flat Bark Beetles are 10 to 14 mm long and range from bright to dull red in colour. They have a very flat body with parallel sides, a triangular head and black antennae. These beetles live under the bark of dead poplar and ash trees near the tree line and are seen in spring-summer.
Source: Wikipedia
How to recognize it
Adults are red, either bright or dull, and their bodies are strongly flattened with parallel sides. They have a triangular head and black antennae.
Source: Wikipedia
Size
They measure between 10 and 14 mm in length.
Source: Wikipedia
Where it lives
They are typically found under the bark of dead poplar and ash trees near the tree line.
Source: Wikipedia
Life cycle
They can change their overwintering strategies to survive cold habitats. Survival mechanisms include extreme dehydration, production of antifreeze proteins and glycolipids, diapause, high-concentration glycerundol, and gut purging to remove ice nucleators.
Source: Wikipedia
When you see it
Adults are most commonly observed in spring and summer.
Source: Wikipedia
Where it comes from
Two subspecies exist: C. clavipes clavipes in the east and C. clavipes puniceus in the west.
Source: Wikipedia
Where it is found in the US
Recorded in 49 of 51 states and DC. Most records: Alaska, Washington, New York, Pennsylvania, Ohio, Virginia, California, Michigan.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: native in North America; native in Canada. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
When are Red Flat Bark Beetles most likely to be seen?
They are usually observed during the spring and summer months.
Source: Wikipedia
What do Red Flat Bark Beetles eat?
They feed on tree phloem and hunt small insects like wood-boring beetles and mites.
Source: Wikipedia
Where can I find Red Flat Bark Beetles?
Look under the bark of dead poplar and ash trees near the tree line.
Source: Wikipedia
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Cucujus_clavipes
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-23 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-23.