Boxelder bug vs Red-shouldered bug
These two are easy to mix up. Here's how to tell a boxelder bug from a red-shouldered bug, and whether either one bites or stings.
Boxelder bug
Boisea trivittata
Red-shouldered bug
Jadera haematoloma
≠The key differences
Boxelder bugs have red lines on black wings and a different head and pronotum shape; they are associated with maple and boxelder rather than soapberry trees.
⚖︎Side by side
| Boxelder bug | Red-shouldered bug | |
|---|---|---|
| To humans | Non-toxic | Non-toxic |
| Size | 9-16 mm long | 8-12 mm body length |
| Colours | Black, Red, Orange | Red, Black, Dark brown, Orange |
| Family | Rhopalidae | Rhopalidae |
| Habitat | Deciduous trees (especially boxelder, maples, ash), nearby gardens, rock piles, building exteriors and sheltered overwintering sites | Edge habitats, gardens and urban landscapes where soapberry-family trees and shrubs (Sapindaceae) occur; often on trunks, branches, seed pods and nearby vegetation. |
| Range | Widespread across much of North America; especially common where boxelder (Acer negundo) and other maples grow | Native to the Americas: widespread in the southeastern and southern United States, Mexico and Central America; also observed in areas where host trees have been planted. |
| Active | Active spring through fall; most visible late summer and fall during mating and pre-overwintering aggregation; diurnal, often basking in sun | Spring through fall in temperate zones; active during the day (diurnal), most abundant when host plants are fruiting. |
| Pest? | Yes | No |
🔍How to spot a boxelder bug
- Black, elongated body 9-16 mm long with three red or orange longitudinal stripes on the pronotum
- Red or orange young nymphs without fully developed wings; adults have red edging on the wings
- Often found on boxelder or maple trees and in sunny aggregations on warm building walls
🔍How to spot a red-shouldered bug
- Red/orange patch across the pronotum and 'shoulder' area contrasted with black or very dark wings
- Small elongated body 8-12 mm long with visible wing pads (in adults) and a tapered head
- Nymphs bright orange-red and gregarious on seed pods of soapberry-family plants
- Found feeding on seed pods of goldenrain, soapberry and related host plants
?Frequently asked questions
What is the difference between a boxelder bug and a red-shouldered bug?
Boxelder bugs have red lines on black wings and a different head and pronotum shape; they are associated with maple and boxelder rather than soapberry trees.
Is a boxelder bug or a red-shouldered bug more dangerous?
Boxelder bug: Non-toxic. Red-shouldered bug: Non-toxic. Boxelder bugs do not bite or sting and are not dangerous. Not venomous or poisonous.
Identification from photos is never certain: don't handle insects you can't identify, and get medical advice for bites, stings or allergic reactions.