Crane Flies

No, that's not a big, weird, scary mosquito

The first time I met a crane fly, it was scary. I was in Viet Nam sitting in back of a truck. What I thought was a large Asian mosquito started flying around me. I was terrified by its size and swung at it. I lost my balance and fell off the truck and landed on my head in a mud pile. If I had landed on a solid road I probably would have broken my neck and would have been the only soldier in the army that was killed by a crane fly.

What are crane flies? These are large insects that closely resemble mosquitoes. They can be very scary looking, particularly if they find their way into your home and start flying around terrorizing everyone. Are they dangerous? No, crane flies are completely harmless. They have a variety of names including “Mosquito Killer”, “Mosquito Hawk”, “Mosquito Eater”, “Gallinipper” and others. They do not eat mosquitoes or any bugs. The adult crane flies eat very little and mostly just nectar.

Crane flies are primitive flies belonging to the Order Diptera and the Family Tipulidae. There are many different species, some are large and others are quite small. The ones that commonly scare people are about an inch long, with a narrow body and very long legs that can exceed an inch in length. The wings are long and narrow.

The larvae are grayish brown in color and are cylindrical shaped. They are often called “Leatherjackets”. The larvae commonly are found in moist areas such as woodlands and around streams. They are found under layers of decomposing leaves and in compost piles. Some species occur in open fields, dry areas including desert environments. A few species can feed on the roots of forage crops and turf grasses. Most species feed on decaying organic matter. They can be important in the soil ecosystem as they process organic material. They are, both in the larval stage and as adults, valuable food for many animals including insects, spiders, fish, frogs, toads, birds and some mammals.

Adult female crane flies usually contain eggs when she emerges from the pupa and often immediately mates with a male if one is available. They often mate while flying. Once the eggs are laid, the adult males and females have a life span of up to two weeks. The eggs are laid in water, in dry soil and occasionally dropped from the air. The eggs are black in color.

Because of their size they can cause panic attacks if they come in your house. They are attracted to light as many insects are and they will fly in an open window or door and start running into walls and furniture. As mentioned, they are medically harmless, but can by psychologically scary.

They usually start showing up in mid-February and hang around until April, depending on the weather. Large numbers may show up and rest on plants and the sides of your house if you live near an area where they may breed.

Make sure all of your windows and doors are closed and that all window and door screens are in good repair. Leave outside lights off during the evening. This won’t guarantee you will never see a crane fly in your house, but it certainly reduces the odds.

They should be considered beneficial insects as the adult flies are harmless and that their biology is such that they contribute to the ecosystem because the larvae (leatherjackets) feed on decaying organic material and help in the decomposition process.

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