Wheel Bug

Benefits of the Wheel Bug


Gardeners especially often wish to eliminate insects from their garden or flower beds, but there is one insect, the wheel bug, that they should actually welcome to their landscapes.


Six legged assassin


Nicknamed the “assassin bug”, this insect could be the object of an action adventure movie.  The bug’s very appearance lends credence toward the impression of it being ready for battle.  Grayish black in color, the bug has a body that seems to be encased in gunmetal armor.  While measuring only about 1 ½ inches long, it has the distinction of being the largest land bug in North America.  The most identifiable characteristic about the insect is the wheel shaped, notched half circle rising up on its back behind the head.


This unique appearance is not merely a facade.  The term “assassin” was bestowed due to the bug’s voracious predatory style; attacking a wide variety of soft bodied insects such as those found feasting on your garden or flowering plants.  This leads to perhaps the second most remarkable characteristic of the bug; its maddeningly slow gait.  With deliberation, the assassin ambushes its target with strikes that are accurate and deadly.  Its march, accompanied with the appearance, has given the bug the similarity to a robot to many.  And, like a robot that has its sights set on a target, the wheel bug slowly stalks its victim before grasping it with its front legs.  A sharp, hard beak is used to pierce an area of the soft body and the prey is injected with a paralytic solution through the wheel’s saliva.  Within moments, the victim is paralyzed and their inner organs begin to dissolve.  The wheel removes the fluids from the prey by sucking it out using its beak.


With an insatiable appetite, the assassin is a valuable asset in woodlands, orchards and gardens.  Aphids, a well known harmful insect that feeds upon many landscape plants, are a favorite meal of the wheel.  Hairy caterpillars are also considered to be preferred prey, which is helpful for saving the foliage of shade trees and bushes that these detrimental creatures are known to defolatiate.


Gardeners and the Wheel


In most cases, gardeners will not even realize that this deadly force is working for their benefit in the landscape.  The wheel bug is a shy, retiring insect that is difficult to spot in its natural habitat.  Its coloration and slow moving traits help it to blend in with its surroundings.  They are most noticeable during the nymph stage, when their black and red bodies may be visible against the dark trunks of the trees or the green leaves of landscape bushes.  There is one very distinct feature of this insect, however, that cannot escape notice even when it is not visible.  The bug is equipped with two reddish orange scent sacs that it uses to disperse a putrid scent when it is startled. While the odor is not as strong as that emitted by its cousin, the stink bug, it is definitely enough to wrinkle the nose.


One trait that the wheel displays as part of its robotic assassin image is that it is not finicky about its prey.  The female of the species has been known to turn on her partner after mating and eat him.  In addition, the insect is also capable of piercing humans with the strong beak as well.  While not a true “bite”, the wound has a sting that varies in intensity according to the person.  It is painful, and can take a few weeks to fully heal.


Although harmful garden insects may not agree, the wheel bug is definitely a beneficial element to a landscape or a garden.  Living in harmony with gardeners when left alone, this insect is a welcome addition.