Large milkweed bug vs Red-shouldered bug
These two are easy to mix up. Here's how to tell a large milkweed bug from a red-shouldered bug, and whether either one bites or stings.
Large milkweed bug
Oncopeltus fasciatus
Red-shouldered bug
Jadera haematoloma
≠The key differences
Milkweed bugs are larger and have a distinctive orange-and-black pattern with a broad orange band across the hemelytra; they feed on milkweed seeds rather than soapberries.
⚖︎Side by side
| Large milkweed bug | Red-shouldered bug | |
|---|---|---|
| To humans | Non-toxic | Non-toxic |
| Size | 12-18 mm body length | 8-12 mm body length |
| Colours | Orange-red, Black, White (small markings on legs/edges) | Red, Black, Dark brown, Orange |
| Family | Lygaeidae | Rhopalidae |
| Habitat | Open areas, meadows, roadsides, and gardens where milkweed grows; commonly on the seed pods and blossoms of milkweed plants | Edge habitats, gardens and urban landscapes where soapberry-family trees and shrubs (Sapindaceae) occur; often on trunks, branches, seed pods and nearby vegetation. |
| Range | Native to the Americas: widespread in the United States and southern Canada (where adults are summer migrants in the north), through Mexico, Central America and the Caribbean into parts of South America | 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 in spring through autumn where milkweed is present; mainly diurnal (active during the day) | Spring through fall in temperate zones; active during the day (diurnal), most abundant when host plants are fruiting. |
| Pest? | No | No |
🔍How to spot a large milkweed bug
- Bright orange-red body with bold black banding across wings and black markings on head and pronotum
- Adult length 12-18 mm, elongated oval shape with wings covering the abdomen
- Aggregates on milkweed seed pods and flowers in conspicuous groups
🔍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 large milkweed bug and a red-shouldered bug?
Milkweed bugs are larger and have a distinctive orange-and-black pattern with a broad orange band across the hemelytra; they feed on milkweed seeds rather than soapberries.
Is a large milkweed bug or a red-shouldered bug more dangerous?
Large milkweed bug: Non-toxic. Red-shouldered bug: Non-toxic. Large milkweed bugs are not venomous and do not present a medical threat. 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.