Insect of the Week - The Wheel Bug

Adult wheel bug
(Photo: Johnny N. Dell, Bugwood.org)

The wheel bug is an assassin in the insect world, literally. The wheel bug belongs in the Family Reduviidae, commonly referred to as assassin bugs, and for good reason! These insects are predators and pierce their prey (soft-bodied insects such as caterpillars, moths, aphids, small beetles etc.) with their beak-like mouthpart and inject a potent saliva. The saliva contains enzymes that quickly subdue the prey and then digest the tissues inside. The wheel bug then sucks this digested liquid from the prey as it shrivels up. What a way to go! Wheel bugs are not aggressive and will try to avoid contact, but can inflict a painful bite if aggravated or handled, so it's best to leave it alone if you run across one.

Wheel bug egg mass and hatched nymphs
(Photo: Johnny N. Dell, Bugwood.org)

The wheel bug is one of the largest assassin bugs in NC; adults measure 1 - 1.25 inches in length. They are very distinct looking, sporting a large, gear-shaped half wheel on their thorax and a large, piercing beak tucked under the head.

In the fall, female wheel bugs lay masses of eggs by gluing them to bark or some other object. Tiny wheel bug nymphs hatch in April and May and begin to feed on aphids and other small insects. As nymphs develop they become larger and thus capable of attacking larger prey. When prey is scarce, wheel bugs feed on other wheel bugs, and female wheel bugs commonly feed on male wheel bugs after mating.

Check out the spectacular video below by Daniel R. Jusino, Rutgers University Entomology Department. It showcases the wheel bug and includes some amazing footage of nymphs hatching, molting, and feeding.