Beverly saw an unusual, large insect on a milkweed plant in our pollinator garden several weeks ago and showed me a photo on her phone. She identified it using Google Lens and warned me to stay away from it because its bite is very painful. When it was still there the next day, I took some photos of it, which was difficult as this insect was shy and kept moving away from me and the camera.
It was a North American Wheel Bug (Arilus cristatus) (or just wheel bug), a species of large assassin bugs and the only one found in North America. It was about 1½ inches long and has the distinctive wheel-shaped armor visible in the photos. Later that day it was still there but had captured a small bee, as shown in the Additional Images gallery below.
The wheel bug feeds on caterpillars and beetles and is generally considered beneficial because most of its prey are pests like the Japanese beetle and tent caterpillars.
When I processed my photos I saw that there were also many small yellow aphids on the milkweed, which were not obvious with the naked eye.
Additional Images
Additional Information
Wikipedia: https://en.wikipedia.org/wiki/Arilus_cristatus
Carnegie Museum of Natural History: https://carnegiemnh.org/so-just-what-is-a-wheel-bug/
Technical Data
The first two images are High Dynamic Range (HDR) images, which consist of three photographs taken at different exposures and combined within my Canon R7 camera. (Please see the Definitions, Software, & Apps page for additional information about this technique.) I used the smallest aperture opening possible to get the most depth of field, as I needed to hand-hold the camera because the insect kept moving. I used a flash unit for the third image because it was in deep shadow.
North American Wheel Bug 1
- Date: 8/6/2025
- Time: 10:31 AM
- Camera: Canon EOS R7
- Lens: Sigma 105mm f/2.8 EX DG OS HSM Macro
- Settings:
- Lens: 105 mm, f/22
- Exposure Bias: -2 EV
- ISO: 6400
- Shutter: 1/1000 sec
- Uncropped image is 6934 x 4617 px
North American Wheel Bug 2
- Date: 8/6/2025
- Time: 10:33 AM
- Camera: Canon EOS R7
- Lens: Sigma 105mm f/2.8 EX DG OS HSM Macro
- Settings:
- Lens: 105 mm, f/22
- Exposure Bias: -2 EV
- ISO: 6400
- Shutter: 1/1000 sec
- Cropped image is 6810 x 4539 px
North American Wheel Bug 3
- Date: 8/6/2025
- Time: 6:46 PM
- Camera: Canon EOS R7
- Lens: Sigma 105mm f/2.8 EX DG OS HSM Macro
- Electronic Flash: Fired
- Settings:
- Lens: 105 mm, f/22
- ISO: 6400
- Shutter: 1/60 sec
- Uncropped image is 6960 x 4640 px