By Curtis Young, CCA, Ohio State University extension
Crane flies (also known as daddy longlegs and mosquito hawks) belong to the Diptera (the true flies) insect order of the Tipulidae family. There are around 15,000 types of crane fly worldwide. Crane flies and mosquitoes belong to a common subgroup of flies, and crane flies look like giant mosquitoes on the surface. Fortunately, crane flies do not have the mosquito-biting / sucking mouth parts for taking a blood meal. Therefore, they do not bite other animals for blood. Some adult crane flies do not eat or feed on fluids from plants in their short lifespan. Adults live longer than 10-14 days.
The larvae of crane flies are maggots, which are called leather jackets because of their tough, leathery outer shell (exoskeleton). Depending on the type of crane fly, the larvae can be aquatic, semi-aquatic, or terrestrial and live in soils that are rich in organic matter and relatively humid for most of the year. Some species can attack living plants that eat root hairs, small roots, outer sheaths of roots and stems, and occasionally eat leaves such as blades of grass.
Adults usually appear in Ohio landscapes during two peak periods. Some species are vigorous in adults in the spring, while other species become adults in the fall. There are currently extremely large numbers of newly emerged adult crane flies in parts of Ohio. Those large numbers of crane flies fluttering over lawns, pastures, and crops are mostly a nuisance, and some of them can find their way into homes.
Like the adults, the larvae occasionally appear en masse on driveways or sidewalks, especially after heavy rainfall. Such a dramatic appearance in a landscape can indicate that the lawn has a straw problem as the larvae are particularly keen to rot. The native species found in Ohio, however, do not harm the lawn grass.
The same is not true of two alien species found in northeastern states and eastern Canada that have now spread to Ohio and Michigan. Both were accidentally imported from Europe. Larvae of the European crane fly (Tipula paludosa) and the pond crane fly (T. oleraceae) feed on the crowns and leaves of living grass plants. Both of these can seriously damage the lawn grass. They are also known to damage grains (wheat, oats, rye, barley, etc.) and other crops, as well as a variety of smaller crops, from sugar beets and beets to cabbage, berries, and carrots.