November, 2012

Assassin Bug

One of the most numerous predatory insects in our area is the assassin bug (Zelus renardii). Although small (about 1/2 inch long), the assassin bug is an efficient killer of other insects, including leafhoppers, caterpillars, bees, aphids, and flies. A number of different species are called "assassin bugs" and most do not have any other more individual common name. The assassin bugs belong to the family Reduviidae, in the order Hemiptera. A lot of insects are called bugs, but this is one of the TRUE bugs, a defining characteristic being the sucking tube-like mouthparts that restrict it to a liquid diet. This feature can be easily seen in the above profile view; it is especially thick in predators vs. plant feeders because it needs the strength to pierce the exoskeletons of prey. While many predaceous insects have modified front legs that help them grip their victims, the assassin bug has a rather unusual adaptation: its front legs are covered with sticky hairs, perfect for snatching small bees and flies as they fly near. One drawback, though, is that if the bug falls into sandy or dusty soil, it gets particles stuck on its legs and must then clean them off. They are therefore rarely seen on the ground, preferring to remain on foliage.