Milkweed Bug (Oncopeltus fasciatus)

Milkweed Bug (Oncopeltus fasciatus)

I found these little insects today resting and munching on our Asclepias tuberosa (Butterfly weed). They are known as milkweed bugs or Oncopeltus fasciatus. According to the University of Arizona Extension the milkweed bugs feed on:

Seeds and tissue of the milkweed plant (Asclepias spp.). In captivity, the bugs feed on shelled sunflower seeds.

I’m trying to figure out the “in captivity” part. Do people keep these insects as pets? Do they house them for some sort of mad scientist experiments?

Whatever the case these insects eat the juices of various varieties of milkweeds which makes them pretty much unpalatable to any potential predators. This is very similar to monarch butterflies whose larvae also ingest milkweed. Depending on how much you like milkweed (and I don’t know anyone who doesn’t, maybe I just don’t know enough people) these orange and black milkweed munchers aren’t welcome inhabitants of the garden.

They are easy enough to pull off or knock off into a container for disposal so they aren’t really a threat. They serve to help control the population of milkweed in the wild and while that may be necessary it’s hard to look positively upon an insect that enjoys dining on my garden. Of course monarchs of all ages are welcome!

What insects are bugging you?


Dave has written since 2007. He gardens on an acre and a half where he raises his 5 children. He enjoys growing vegetables, herbs, and propagating plants. Dave works as a real estate agent in Spring Hill, TN.

This Post Has 13 Comments

  1. I CANNOT have enough time to whine about squash vine borers. Due to their presence I have not grown a SINGLE full grown this summer and am thus SQUASH-less (the tragedy!). I could attempt other varieties other than the regular, zucchini, pumpkins, acorn, butternut, buttercup and spaghetti ones I tried this year, but it even attacked my CUCUMBERS, so I think it'll attack everything in my garden at this point. *SIGH*

  2. Hate those bugs. I never got the first squash either. I think a conspiracy is in the air.

  3. Dear Dave
    I had these little guys one year and they were fascinating .. I think I took some good pictures too .. I'll have to go check my "weed" and see if they are there this year ?
    Great picture yourself lad ! LOL
    Joy : )

  4. Never seen this creature before. Maybe, because I don't have milkweeds. Looks innocent and even elegant in his orange/black outfit.

  5. I have a lot of milkweed, but I see these bugs on the hyacinth bean vines instead.

    PS We had a Monarch girl emerge yesterday.

  6. these same bugs are bugging me! We found eggs on the milkweed, now we are going to try and raise to the caterpillar stage….it's very exciting for me!!

  7. I've been looking for these on mine but so far none. I am sure they'll be here soon.

  8. I've been blessed, my first year gardening and not any real pests to destroy anything! The one bug that does annoy me (trying really hard to not use "bug" twice in one sentence, LOL) is the big red ants that fall on me when I go after my okra…those little monsters hurt!

    and a side note…I very nearly freaked out at that little pair of scissors in the Progressive ad on the left…I thought it was a bug…but then again, I haven't had my coffee yet either…Welcome Monday! LOL

  9. Thanks so much for this, Dave. I have been watching these bugs for the last couple of years, trying to decide if they should be left alone or not. There are many of them though, I had better get on it. Our worst bug by far this year has been the harlequin. It took the ornamental kale down to stubs, then ate the stubs and have moved to my dahlias. They are getting squished between my fingers, gloved or not now.

  10. Huh, interesting! They almost look like a fire fly. Hopefully they don't become invasive.

  11. In captivity? Yes, some people do keep them as pets! They don't bite and rarely escape, even after they grow wings as adults. They are more charismatic than an ant farm, and would make a great gift for a budding entomologist.

  12. CJ,

    I can see where those folks who might like entomology to be interested in it but outside of that area I doubt many would keep them. Obviously studying the life cycle of insects is important to understanding our ecosystem. This gardener is highly supportive of entomologists as their work helps with our favorite past time!

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