Aquatic insects that belong to the family Corixidae are commonly known as corixids or water boatmen.  In Utah they inhabit a wide variety of water ranging from slow moving canals to shallow, stagnant alkaline pools.  Water boatmen constitute the largest group of water bugs, with well over 100 species occurring in North America.  They are perhaps the most abundant insect in the marshlands northwest of the Salt Lake City International Airport.  The adults are easily recognized by their small size (3-11 mm), brown to grayish tan color, large eyes, front legs that are extremely shorts and their rapid swimming action.

The winter is often passed in the adult stage, with the ability to remain active even in waters covered by a layer of ice.  Eggs are laid in the spring and are attached to stems and leaves of various water plants.  The incubation period is one to two weeks.  There are five nymphal stages that require about a week for each.  There are usually two  generations per year.  The adult has a fully functional pair of wings but usually remains in the water.

 As do all other aquatic bugs, they lack gills and get air at the surface of the water.  The frequently carry a bubble of air under water, either on the surface of the body or under the wings, thus enabling them to stay under water for long periods of time.  Most water boatmen feed on algae and other aquatic organisms, but are also predaceous on midge and mosquito larvae.

Water boatmen play an important role in aquatic communities because they help break down decaying plant material and serve as a food source for fish and birds.

For over three hundred years water boatmen have been used in commercial trade.  In the U.S. alone, tons of these dried insects are shipped to other countries each year as bird, fish or turtle food.

While water boatmen usually remain in the water, during particularly hot and dry summers when water sources dry up they readily fly from distant wetlands. Upon entering the city they are attracted to lights in enormous numbers.  The adults appear to die naturally, and can be found in heaps on the ground beneath lights.  Some people complain of the odor given off by the decaying insects.  Even though they area nuisance, they pose no health problems. 

topˆ