What’s that orange bug on your milkweed?

It’s simple. Those orange bugs on your milkweed are milkweed bugs! And these little fellas (or gals) above are one of the later-stage nymphs of the insect.

Milkweed bugs come in two versions. Large Milkweed Bugs (Oncopeltus fasciatus) and Small Milkweed Bugs (Lygaeus kalmii), both of which feed on the seeds of milkweed plants. You can see them above clustering on what might be the pods of tropical milkweed (Ascelpias curassavica) this week at the Toronto Botanical Garden.

Apparently, there’s also a very similar-looking False Milkweed Bug (Lygaeus turcicus) that prefers the seed of false sunflower (Heliopsis helianthoides). And the Eastern and, to some degree, Western Boxelder Bugs (Boisea spp.) look similar, too.

If you look carefully, you can see the bug’s piercing/sucking tube folded under its body in the bigger one near the top. (The tiny orange insects are just aphids.)

This fact sheet from the University of Wisconsin tells you all about these rather decorative creatures. According to the Missouri Botanical Garden, these sucking insects are “more a nuisance than a threat.”

In fact, when I nabbed a passing TBG staffer to help me ID these on Tuesday, they first thought I was talking about the plant, and said it was invasive. A few seeds lost to sucking insects might not be so bad. So perhaps they’re doing gardeners a favour by noshing on the tropical milkweed, which has also come into disfavour in Monarch butterfly-friendly circles. The current thinking is that we should only grow milkweed that is native to our area.

You can probably make out some of the adults in this cluster. The X-shaped markings lead me to think these are the Small Milkweed Bug. What you you say?
You can probably make out the adults in this cluster. Their X-shaped markings lead me to think these are the Small Milkweed Bug. What do you say?

Don’t want them on your milkweed? The easiest thing is to knock them off the plant into some soapy water. They’re pretty slow moving and their colour makes them easy to spot.


    1. They’re quite gregarious when young. You can’t really miss them. I didn’t spot them on the common milkweed, which was growing nearby, so perhaps the pods on the tropical milkweed are thin-skinned and easier to pierce?

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