May, 2006

Wheel Bug

Our featured backyard inhabitant this month is the distinctive wheel bug (Arilus cristatus). A member of the order Hemiptera, or true bugs, this 3/4 inch long insect is a voracious predator. All true bugs possess a mouth in the form of a jointed tube. They feed by puncturing and sucking out juices. In the case of many herbivorous bugs, this means plant stems, leaves and fruits. However, the same structure in predatory bugs is used to stab other insects and drain out their bodily fluids. Because the wheel bug often preys on caterpillars and various plant pests, it is considered beneficial. While not very common, these ambush predators do show up occasionally in gardens and yards. Some years I don't see any at all and other years the nymphs begin to appear in late spring. The strange crest on the back of the insect is unique and its purpose is unknown. Although capable of flight, these bugs prefer to crawl and hide when threatened. Handling them is discouraged as they can make a painful stab with their proboscis in self defense.