Bug FAQWestern Boxelder Bug
Boisea rubrolineata · Order: Hemiptera · Family: Rhopalidae
Also called: Western Box Elder Bug
Western boxelder bugs are small, 9 to 13 mm long, with black and red markings on adults and bright red-gray nymphs. They live in western North America and feed on boxelder trees.
Source: Wikipedia
How to recognize it
Adults have a black thorax and wings crossed by red lines and a red abdomen; nymphs are bright red and gray.
Source: Wikipedia
Size
They measure about 9 to 13 millimetres in length.
Source: Wikipedia
Where it lives
They are found across western North America.
Source: Wikipedia
What it eats
Both nymphs and adults feed on boxelder trees.
Source: Wikipedia
When you see it
In fall and winter adults often migrate indoors to hibernate.
Source: Wikipedia
Where it comes from
Their native range is western North America.
Source: Wikipedia
Where it is found in the US
Recorded in 12 of 51 states and DC. Most records: California, Oregon, Washington, Idaho, Nevada, Arizona, Utah, Montana.
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
Same family (Rhopalidae)
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Boisea_rubrolineata
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-22 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-22.