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The Myths, The Facts: The Crane Fly 

They Are Not What You Think They Are

You have probably seen at least one of them perched on your wall or ceiling, flying erratically around your porch light in the evening hours. Perhaps you find them clinging ominously to your screen door.

The Crane fly.

Crane flies are often the subject of folklore due to their seemingly mysterious nature and large size. Their large wing span, long twig-like legs and knobby knees make good material for make believe. Unfortunately, make believe often leads to misconceptions.

We're here to set the record straight and give crane flies the respect they deserve. Commonly known as the "mosquito hawk" or "skeeter eater," these innocuous insects actually feed only on plant nectar and in most instances as adults, do not eat at all. We'd love to believe they seek out mosquitoes and eat them in abundance, but the fact is, they don't.

According to Contra Costa Mosquito & Vector Control District Scientific Programs Manager Steve Schutz, Ph.D., "Larvae of most crane fly species feed on decaying plant material and are not predators of mosquito larvae since they crawl in the mud and can't really swim, they'd have a hard time catching a mosquito larva if they wanted to".

While crane fly larva have been known to cause damage to residential lawns (mainly due to root feeding), many other environmental conditions and garden pests can cause such problems as well. A vigorous lawn can usually recover from crane fly larva damage and adult crane flies will not harm your lawn at all. One of the most famous fallacies surrounding the crane fly is that it is not a crane fly at all, but rather a mosquito. When the two insects are compared side-by-side (see photo above), it becomes quickly evident there is a rather sizeable difference between the two insects.

"Adult crane flies may resemble mosquitoes to some people;, however, they lack scales on their wings and they lack a proboscis for feeding on blood. This superficial resemblance, and the large size of some crane fly species, does cause some people to become alarmed because they mistake them for 'giant' mosquitoes," Schutz points out.

Crane flies are prominent in the summer months as the adults emerge and mate, the females depositing eggs. To avoid these potential houseguests, be sure that your window screens are sealed and that your doors are shut. These measures will also keep out mosquitoes.

What good are crane flies, especially if they don't eat mosquitoes?

Like many insects, they exist as part of the eco system and live their days to perpetuate their species.They are harmless and only live for about three days once they emerge from the water or wet soil. They simply want to mate during their adult stage and couldn't bite if they wanted to. So, the next time you find a crane fly in your house, give 'em a break. Gently escort them out of the house and on to greener pastures.

May, 2011