Long-legged Skeeters are Actually Crane Flies
Ro Wauer, March 21, 2004, The Victoria Advocate, © 2004
Crane flies are later than normal this year. But it seems that lots of things are later than usual this year. While crane flies sometimes appear in South Texas as early as late January or early February, the first did not appeared this year until March. I discovered a few crane flies, mostly paired, in weedy areas in my back yard. I did not find the huge numbers that occur at times. Huge swarms occasionally are found in cool, damp places, such as in culverts or under concrete bridges. Sometimes these swarms bob up-and-down, by raising and lowering their bodies by bending their long legs, in a really strange manner. This behavior is not well understood, although some entomologists suggest that it may be a way for the males, that dominate the swarms, to attract passing females. Others suggest that it is more related to safety-in-numbers. But whatever the reason, it is a little odd and also a little spooky.
Crane flies are those huge mosquito-like insects that, when flying about, are slow and clumsy, sometimes even bumbling into lights, doors, and even mouths of predators. These daddy-long-legs of the air have also been called "drolls of the insect world," due to their unassuming personality. They are not at all like most other members of the Diptera or the True Fly Family, that include such well-known creatures as the house fly, mosquito, fruit fly, midges, and gnats. Most of these other flies are sun-loving creatures. There are about 90,000 Diptera species worldwide, including almost 17,000 in North America. Dragonflies, mayflies, and stoneflies are not true flies.
All of the true flies possess a single pair of wings and a pair of short knobbed projections called "halteres," located on their bodies just behind the wings that serve as balancing organs. They are easy to see on crane flies, due to the insect's large size. Halteres act as a second pair of wings, like gyroscopes, vibrating rapidly in opposition to the insect's wingbeat; when the wings move up, the halteres move down. If one of the halteres is removed, the insect can no longer fly; it sideslips and yaws, out of control. In people, this sense of balance derives from structures in the inner ear. If something goes wrong with this mechanism, a person has difficulty in navigating, and even standing up.
Crane flies, unlike their mosquito cousins, have no sting or bite; they are totally oblivious to humans. One usually can get within a few inches for a close-up examination. Except when disturbed, they will stay in place. They can be described as having a narrow abdomen, narrow wings, and absurdly long legs. Occasionally they can be found walking about on tree trunks or logs or damp leaf-cluttered ground. Many of those found on the ground or on logs are males in search of a female. They may even sit beside a pupa until the female emerges and then mates, scarcely before she has freed herself of the pupal skin. The female crane fly, once filled with eggs, deposits them on the surface of rotting wood or pushes them into the soft pulp. The larvae, tiny greenish grubs, crawl about below the surface of the ground, feeding on roots and seedling plants, sometimes killing them. Although adult crane flies are most obvious and attract our greatest attention, the larvae, that are rarely evident, are biologically more important.
In spite of the relative unimportance of the adult crane flies, they are far more interesting at this stage than at the larval stage. Finding a swarm of these long-legged insects on some damp structures, or seeing several individuals flying about one's property on a warm spring day, seems to be a telling signal that the new season has truly arrived.