Giant Water Bugs

One of the largest insects commonly encountered in Iowa is the giant water bug. These moderately common aquatic insects live in lakes, ponds and quiet streams, but they are strong fliers, they are attracted to lights, and consequently, often are found a considerable distance from water. They may be found in the yard or street under a street lamp, or they may have crawled by accident into the house or other building.

Giant water bugs are 2 1/2 inches long and brown in color. The body is flat and elongate oval in shape but pointed at both ends. The front legs are enlarged and pincer-like with a resemblance to praying mantis front legs. A short beak is visible on the front of the underside of the head. The legs and beak combine to make the giant water bug an effective predator. They feed on other aquatic insects, snails, tadpoles and even small fish.

Giant water bugs are in no way related to, or connected with the household cockroaches that are nicknamed 'waterbugs.' The giant water bugs are harmless and interesting. They do no harm to crops, structures, people or pets and they will not reproduce or establish indoors. The worst that can happen is a painful bite if they are handled carelessly.

Special controls for giant water bugs are not necessary. Most of them die quickly if they can not get back to water.

Line drawing of a giant water bug
Giant Water Bug

This article originally appeared in the May 6, 1992 issue, p. 77.


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