I saw my first wheel bug of the year today. Since they hatch in spring, they are around throughout the warm months, but I seldom notice them until late summer.
Wheel bugs (Arilus cristatus) are no doubt the most unusual-looking insects around here, and you will never mistake them for anything else. People usually describe them to me as looking like dinosaurs.
The adult wheel bug is gray and about the size of a grasshopper. It has a long neck, a head that looks too small for its body, bulging eyes, and what looks just like half of a gear wheel on its back. They do not have a complete metamorphosis, but the young (nymphs) are bright red and look a lot like ants. They carry their abdomens curled upward and they don't yet have wheels. As they grow and molt, they get grayer, but their wheels do not appear until they are nearly full grown. Wheel bugs of all sizes have strong beaks curved under their heads and as long as their heads. The adults are strong fliers.
An adult wheel bug.
Wheel bugs are members of the assassin bug family (Reduviidae), and they are fierce predators. They are catlike in their hunting habits. The bug will sit still for long periods or walk slowly along plants, patiently stalking its prey. When it gets close enough, it grabs the victim with its front legs and stabs it with its beak.
Wheel bugs do not have jaws. They are piercing/sucking insects, just like their "cousins" the plant-juice-feeding bugs. When the wheel bug jabs its prey, it injects digestive enzymes that liquefy the victim's body contents, then it uses its beak to suck the juices out. They do not feed on mammalian blood.
Since wheel bugs are so odd looking, they are definitely among the insects that curious children might be tempted to pick up. Please warn your little ones NOT to touch them. Wheel bugs definitely can and will "bite" by stabbing you with their beak. Fortunately, I have never been bitten, but people who have describe it as very painful and worse than a bee or hornet sting. The bite turns red and swells and sometimes takes weeks to heal.
Wheel bugs are considered beneficial, since they kill many pest insects. They have even proved to be very fond of stink bugs, although there will never be enough wheel bugs to make a dent in the stink bug population! So please don't kill them, but do keep your distance.
There are other assassin bugs, but none are as noticeable as wheel bugs. The thread-legged bug is another unusual-looking creature, and about as different from the wheel bug as another assassin bug could be. It is a small, delicate insect about inch long. It looks much like a miniature walkingstick insect, with an extremely long, thin body and long, thread-like legs. It walks on its middle and rear sets of legs and holds its front legs up to grab prey. Like the wheel bug, this dainty little bug also has a strong curved beak for stabbing prey.
Thread-legged bugs are nocturnal and usually found in barns and old buildings, in brush piles and under bark. They feed on other insects and spiders.
The kissing bug or conenose bug is an assassin bug found in the southern US and it feeds on mammalian blood. It usually feeds on wild animals but occasionally attacks humans and domestic animals. These bugs have a painless bite because their purpose is to get a meal of blood without being noticed. They usually bite around the face and mouth, hence the name kissing bug. We do not have kissing bugs here, but you could encounter them in Florida or south Texas.
Send your insect questions to Claire Stuart by email at email@example.com or write her (with self-addressed stamped envelope) in care of Living Section, The Journal, 207 W. King Street, Martinsburg, WV 25401.