Q: I find large, mosquito looking insects in my house. They do not seem to bite but I want to know if this is really true. What can you tell me about them?
A: You are describing a crane fly from Tipulidae, which is the largest family of Diptera. Diptera has about 1,500 species in North America and 12,000 species worldwide. Crane flies are not mosquitoes at all and you are correct – they do not bite. Crane flies live in fresh water and moist soil but you can rest easy since they do not feed on humans or animals. The adult stage does not feed at all but merely is alive to reproduce.
The larval stage has chewing mouth parts and feeds on decaying leaves and other organic material. The larvae, called “leatherjackets,” because of their tough, outer skin are usually found in damp soil feeding on decaying vegetable matter. The maggots have no legs with poorly developed heads. They are about one inch long when mature and normally found in poorly-drained soils.
Even though you may see them in large numbers we generally considered them beneficial because crane fly larvae are an important part of the decomposition cycle. One other important thing to note is crane flies carry no disease and therefore it is not necessary to manage or chemically treat them.