Wheel Bug

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My husband, Harry, was working in the backyard and called my attention to an interesting insect he had discovered. It was a Wheel Bug (Arilus cristatus) and the unique spiky wheel-like formation on its back is the source of its common name.

Arilus cristatus

According to Bug Guide, it feeds on caterpillars and other insects and is considered beneficial. Its beak is used to pierce its prey and suck out the juices. The beak can also inflict a painful bite, so I kept my distance.

Here it is feeding on a Common Pillbug (Armadillidium vulgare). In some ways this seems rather gross and yet, is it all that different from me sucking orange juice through a straw?

Arilus cristatus feeding on Armadillidium vulgare

Although this bug is only 1½ inches long, it reminds me of a miniature prehistoric animal.

Arilus cristata close-up

I’m glad to know it’s part of our backyard “zoo” and am pleased to add it to our insect list. I’m afraid backyard insects will now be scarce until spring. If you see any, I’d be glad to hear about it.

11 thoughts on “Wheel Bug”

      1. Thanks for letting me know. I haven’t seen any lately but will keep watching.

  1. We have lots of similar bugs like this in Utah that are quite large, slow and armored. Although I’ve observed them for a little while (they are so cool!), I’ve never noticed if they have a wheel. Ours are also more interestingly colored with, if my memory serves me, red or orange trim. There also seems to be several different kinds of these creatures but for all I know that could just be different life stages or sexes. I will be sure to pay more attention come spring and thanks for the great pics!

    1. Keli. Interesting to know that you have seen similar bugs in Utah bugs that are larger and more colorful. I’m wondering where you see them – on hikes? in the yard? On plants? Thanks for sharing the information.

  2. What a neat little guy (or gal, as the case may be) – the wheel reminds me of a circular
    saw blade. How big was it and did the information you found indicate the purpose of
    the unique “backbone”?

    1. Yes, Beth, I agree with the circular saw blade image. It was about 1/2 inch tall and, no, I didn’t find any reason for the unique “backbone”? There must be some reason why it evolved that way but it’s beyond me at this point.

  3. Aunt Betty this is Parker and I just found a big wheel bug on my porch. Is there supposed to be wheel bugs in Missouri?

    1. Good for you, Parker. Yes, according to what I read they are fairly common in Missouri. However, they are very shy and not very many people have seen them. They have a wicked bite, so you won’t want to handle him. I’m really glad to know of your special find.

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