thumb|right|North American wheel bug nymph
Arilus cristatus, also known as the North American wheel bug or simply wheel bug, is a species of large assassin bug in the family Reduviidae and the only species of wheel bug found in the United States. The North American wheel bug is most active in daylight, residing in leafy areas and hiding whenever possible. Known habitats of the North American wheel bug include sunflowers, goldenrod, cotton, trunks of locust trees, and various fruit and tree groves. Despite the prevalence of the North American wheel bug in many habitats, the information compiled concerning the species is haphazard and incomplete. They move and fly slowly, and in flight produce a noisy buzzing sound. As with other assassin bugs, the proboscis arises from the anterior end of its long, tubular head and unfolds forward when feeding.
A. cristatus possesses two scent glands (red-orange in color) that can be ejected from its abdomen with two distinct chemical functions; one gland used for defense and one gland utilized for breeding behaviors.
North American wheel bugs exhibit armored forewings and membranous hind wings which allow this species to take flight. As a result of its inability to move swiftly, A. cristatus rely heavily upon camouflage, the effect of their bite, or the production of unpleasant odors in order to avoid predation.
Distribution
North American wheel bugs are most common in eastern Canada and the United States, and their range extends into Mexico and Guatemala. a western hemisphere genus, only A. cristatus is found in the United States. Secreted glue serves as an adhesive which maintains the cluster formation of the eggs. The eggs will hatch in the following spring into eight-millimeter-long, red nymphs, which will undergo five molts until they reach the adult stage the following summer.
After the nymphs hatch, the average length of each molt is roughly 18.8 days, though the interval of the 5th and final molt prior to the adult stage is the longest. Eggs generally hatch in the beginning of May and finally mature into adults by July. Overall, it takes roughly 94 days for nymphs to reach maturity. However, the phenology of this life cycle varies, based upon the climate which the population occupies. For instance, communities in warm climates may not overwinter as eggs. Of the 12 clusters of eggs monitored in the lab, 10 were ravaged by parasites which prevented the eggs from hatching normally.
Although A. cristatus is a welcome agent of pest control, this species also preys on several ecologically beneficial species, such as lady beetles and honey bees. Furthermore, the vicinity of the injury is known to become heated and irritated. A white crust sometimes forms around the wound during the healing process, though it eventually deteriorates, leaving the small puncture wound visible. Discomfort may persist for two weeks and up to six months in some cases. However, the latter timeline is frequently attributed to allergic reactions or recurrent infections of the original wound.