Delta Journal

by Bob Thomas

Those sultry days during winter and very early spring are the times when we are invaded by those large insects that look like huge mosquitoes. Some may giggle if you are anxious about these giants and tell you that they are mosquito-hawks, so named because they are thought to eat mosquitoes (which they don’t).

These “Texas-size mosquitoes” are actually crane flies, members of the fly order (cousins of house flies and mosquitoes) and the Family Tipulidae. There are 12,000 species of tipulids worldwide, with 1,500 species occurring in the U.S. Adults are sometimes called Daddy-longlegs, because they look like harvestmen (a group related to spiders that are properly called by that name) with wings. The larvae are commonly known as “leather jackets” due to their tough skins.

Crane flies frequent moist areas and the adults are most active at twilight and around lights where a familiar sight is their awkward bumping against windows and clumsy flight through open doors. Species of the common local genus (Tipula) are short-lived as adults, their sole mission being to reproduce their kind. They don’t even eat - they just mate and then die. In early spring the males are frequently seen in aggregations doing an up-and-down dancing flight around vegetation. As females are attracted, pairing occurs and the duos land on nearby plants to complete their mating rituals. Depending on the species, eggs are laid in moist soil, moss, leaf litter, rotten logs, or water and development begins. Feeding habits are varied, but immature crane flies normally feed on decaying vegetation, roots, fungi, or even each other.

Larvae may become economically important if they attack the root of valuable crops. The principal importance of crane flies is the ecological value of their larvae in aquatic and semiaquatic environments where they are involved in the breakdown of organic material (they are detritivores) and where they are essential in the food chains of many different animals.

Also published in Nature Profile, The Times Picayune, March 24, 1982.