Bug FAQRoughened Darkling Beetle
Upis ceramboides · Order: Coleoptera · Family: Tenebrionidae
Source: Wikipedia
The roughened darkling beetle lives under the bark of fire-damaged birches and sometimes on willow or aspen. Its larvae feed on the inner bark rich in mycelia and on sapwood, and they pupate under the bark for two to three years before emerging in spring. It is now found only in northern Sweden’s coast and in parts of Canada and Alaska.
Source: Wikipedia
How to recognize it
Upis ceramboides is a wood-living beetle that benefits from forest fires.
Source: Wikipedia
Is it a pest in the house?
In winter it can be found indoors when firewood is burned.
Source: Wikipedia
Where it lives
It is most common beneath the bark of fire-damaged birches, but also appears on willow and aspen. In Vindeln municipality it is known as köksskörven because it can be found indoors when firewood is burned in winter.
Source: Wikipedia
What it eats
Larvae thrive on the inner bark that is rich in mycelia and on the sapwood.
Source: Wikipedia
Life cycle
They develop into pupae under the bark during summer and remain in that stage for two to three years. Adults emerge and reproduce in the following spring.
Source: Wikipedia
When you see it
Reproduction takes place in spring.
Source: Wikipedia
Where it comes from
The beetle now occurs only in the Norrland coast of Sweden and in Canada and Alaska.
Source: Wikipedia
Where it is found in the US
Recorded in 17 of 51 states and DC. Most records: Alaska, Minnesota, Wisconsin, Idaho, Michigan, South Dakota, Montana, Maine.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: native in North America; native in Canada; native in United States. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
Why do they appear in my house?
They can be brought inside on firewood that is burned during winter.
Source: Wikipedia
Same family (Tenebrionidae)
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Upis_ceramboides
Look it up elsewhere: GBIF · iNaturalist · BugGuide · Wikipedia
Text written 2026-10-25 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-25.