Bug FAQSerrated Darkling Beetle
Iphthiminus serratus · Order: Coleoptera · Family: Tenebrionidae
The serrated darkling beetle has a moderately wrinkled prothorax with slight serrations along the sides. It lives in rotting conifer logs, especially pine, and will also eat chick feed when kept in captivity. Its range covers much of western North America, including states such as California, Idaho, and Washington, as well as British Columbia.
Source: Wikipedia
How to recognize it
The beetle’s prothorax is moderately wrinkled with modest serrated edges.
Source: Wikipedia
Where it lives
It is found in rotting coniferous logs, especially pine wood. In captivity it will eat chick feed and decaying wood.
Source: Wikipedia
What it eats
Its diet includes chick feed and rotting wood.
Source: Wikipedia
Where it comes from
It occurs across western North America, including many western US states and British Columbia.
Source: Wikipedia
Lookalikes
Former subspecies I. sublaevis and I. salebrosus are now treated as synonyms of this beetle.
Source: Wikipedia
Where it is found in the US
Recorded in 13 of 51 states and DC. Most records: California, Oregon, Washington, Idaho, Montana, Wyoming, Arizona, New Mexico.
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
What does the serrated darkling beetle eat?
It feeds on chick feed and decaying wood.
Source: Wikipedia
Where is this beetle found?
It lives in rotting pine logs and other conifer wood in western North America.
Source: Wikipedia
How can I tell this beetle apart from similar species?
I. sublaevis and I. salebrosus were once considered separate but are now synonyms of I. serratus.
Source: Wikipedia
Same family (Tenebrionidae)
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Iphthiminus_serratus
Look it up elsewhere: GBIF · iNaturalist · BugGuide · Wikipedia
Text written 2026-10-23 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-23.