A predatory wheel bug An adult wheel bug (Arilus cristatus) climbing on a milkweed. (more) wheel bug insect Also known as: Arilus cristatus Written by Melissa Petruzzello Melissa Petruzzello (she/her) is Assistant Managing Editor and covers plants, algae, fungi, insects, spiders, renewable energy and environmental engineering. She also handles certain topics in Christianity,... Melissa Petruzzello Fact-checked by Britannica Editors Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree.... Britannica Editors Last updated Apr. 22, 2026 •History wheel bug, (Arilus cristatus), species of large, primarily North American assassin bug named for the distinctive wheel-like crest on the top of its thorax. The insect is a top predator with a wide range of prey, including defoliating caterpillars, sawfly larvae, and the invasive brown marmorated stink bug, and is generally considered beneficial to gardens and wild ecosystems. It is found throughout much of the southern and eastern United States and into Mexico and parts...

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