You may think a gnat is just a gnat. But to an entomologist, it’s a fungus gnat, eye gnat, gall gnat, sand gnat, or any number of other small biting flies that are often mistaken for gnats, such as the fruit fly.

Gnats are small flies of the suborder Nematocera, which also includes midges, craneflies and mosquitoes. Whether we like them or not, gnats serve a purpose in nature. They are an important food source for birds, bats and larger insects. They also pollinate flowers.

They are not blood-thirsty like their cousin the mosquito. In fact, some adult gnats don’t even eat during their short lifespan. Gnat larva, which hatch from eggs laid in moist soil and other wet environments, feast on fungus, algae or plants.

Besides humidity, a gnat’s life cycle also depends on temperature. Take fungus gnats , for example. The fungus gnat – a common indoor pest that thrives in the overwatered soil of potted plants or greenhouses – lives out its life cycle in three to four weeks at temperatures of 77 degrees Fahrenheit or higher. Temperatures that are too hot can kill them (some horticulturalists have used a ‘bake-out’ method to rid greenhouses of fungus gnats by heating the soil to a temperature the gnats cannot withstand). On the other extreme, fungus gnats that live in Alaska can survive temperatures lower than 25 degrees below zero by freezing their bodies.