Large milkweed bug vs Red milkweed beetle
These two are easy to mix up. Here's how to tell a large milkweed bug from a red milkweed beetle, and whether either one bites or stings.
Large milkweed bug
Oncopeltus fasciatus
Red milkweed beetle
Tetraopes tetrophthalmus
≠The key differences
Milkweed bugs are true bugs (Hemiptera) with a more elongated body and visible beak; they lack the beetle's hard elytra and divided eyes.
⚖︎Side by side
| Large milkweed bug | Red milkweed beetle | |
|---|---|---|
| To humans | Non-toxic | Non-toxic |
| Size | 12-18 mm body length | 9-16 mm body length |
| Colours | Orange-red, Black, White (small markings on legs/edges) | Red, Black |
| Family | Lygaeidae | Cerambycidae |
| Habitat | Open areas, meadows, roadsides, and gardens where milkweed grows; commonly on the seed pods and blossoms of milkweed plants | Open fields, meadows, roadsides and other sunny places where milkweed grows |
| 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 | Eastern and central North America (Canada and United States), wherever native milkweeds occur |
| Active | Active in spring through autumn where milkweed is present; mainly diurnal (active during the day) | Late spring through summer; most active in warm daytime hours |
| 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 milkweed beetle
- Bright red elytra with large black spots over a compact, rounded body
- Eyes deeply notched so antennae appear to arise between divided eye lobes ("four-eyed" look)
- Shortish antennae for a longhorn beetle and black legs/head
- Almost always found on milkweed plants in summer
?Frequently asked questions
What is the difference between a large milkweed bug and a red milkweed beetle?
Milkweed bugs are true bugs (Hemiptera) with a more elongated body and visible beak; they lack the beetle's hard elytra and divided eyes.
Is a large milkweed bug or a red milkweed beetle more dangerous?
Large milkweed bug: Non-toxic. Red milkweed beetle: Non-toxic. Large milkweed bugs are not venomous and do not present a medical threat. Not dangerous or venomous.
Identification from photos is never certain: don't handle insects you can't identify, and get medical advice for bites, stings or allergic reactions.