The Wheel Bug Looks Harmless—Until It Attacks (2025)

Wheel bugs are unassuming until they strike. They spend most of their time hiding, using leafy plants as cover. Their markings provide camouflage, which they use to great effect. That’s probably a good thing for them, too, as their membranous wings make for noisy, clumsy flight. But make no mistake—wheel bugs are called assassin bugs for good reason.

As shown in this video, a caterpillar munches happily on a plant while an assassin bug approaches. In a split second, the bug strikes, using its beak to inject tissue-dissolving saliva. The caterpillar is no match for the assassin and flails in agony as the bug partakes in its next meal. Nature can be a brutal war, and no bug is better equipped for conflict than the North American wheel bug. Let’s learn more about this vicious bug, how it operates, and why its caterpillar prey stood no chance.

North American Wheel Bug Facts

The North American wheel bug(Arilus cristatus) is a member of the Reduviidae family, and the only type of wheel bug that lives in North America. They grow to 1.5 inches long, and adults typically have a gray or brownish color. As for the nymphs, like the one in this video, they also have darker tones except for their bright red or orange abdomens. It’s called the wheel bug due to the distinct, serrated crest that protrudes from the top of its thorax.

Its habitats include sunflowers, cotton, locust tree trunks, and fruit or tree groves. As previously mentioned, wheel bugs are not graceful flyers. Plus, they move slowly on their feet, so they prefer to keep themselves in the shadows as much as possible, even though they usually hunt in the daytime. Wheel bugs usually eat caterpillars, beetles, orange dogs, and cabbage worms. The particular way they acquire their food sources has provided them with their colloquial name, the assassin bug. It’s also the biggest bug in the “assassin” category.

Indeed, the wheel bug is a cold-blooded killer. What it lacks in grace, it makes up for in viciousness. When it homes in on a target, the wheel or assassin bug grabs it and pins it down with its front legs. The bug then drives its beak into the prey, which quickly paralyzes it and dissolves its innards. When the prey’s insides turn to fluid, the assassin bug drains the liquid for nourishment. It may not eat the entire body, but it certainly makes quick work of the organs.

Caterpillar Crunch

As shown in this video, the caterpillar seems blissfully unaware of its approaching death. While assassin bugs move slowly and surely, they aren’t as stealthy as they seem. In that way, caterpillars make the perfect prey for wheel bugs. Their eyesight is poor. Unlike similar creatures, caterpillars have six simple eyes on each side of their head. These eyes, called ocelli, can only distinguish light and dark. They can’t distinguish shapes or figures, such as an approaching assassin. The caterpillar had no idea what was coming.

Assassin bugs may be feared in the insect kingdom, but they have a healthy symbiotic relationship with humans. Many gardeners and farmers consider them valuable predators because they consume a wide variety of bugs and grubs that eat crops. However, they are also known to occasionally eat agriculturally beneficial creatures like ladybugs and honey bees.

Assassin bugs are also known to be highly aggressive. Assassin bugs hatch and immediately display aggression, even against their own species. There are bigger predators out there, too, so the assassin bug will attack or release a foul-smelling scent when threatened. If that fails to do the trick, they will bite to defend themselves. Normally, assassin bugs are pretty indifferent to humans. If they are mishandled, however, they will bite humans, resulting in a bite that is more painful than a wasp sting. It won’t kill you, but it will hurt for several days to weeks. In any case, don’t mess with the North American wheel bug.

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