County of San Diego
They look like giant mosquitoes, or daddy-longlegs with wings, and they fly like crazy bumper-car drivers, bouncing off walls, each other, ceilings and light sources.
But they’re nothing to be afraid of, said Chris Conlan, the County’s supervising vector ecologist.
They’re crane flies – also known as “mosquito hawks,” “skeeter-eaters,” and “daddy longlegs.”
Conlan said they’re harmless to people and that this is the time of year you usually spot them in San Diego County, after the rains and as spring temperatures start to warm up. They’re big for bugs. Their bodies sometimes reach an inch or more in length, but they can look even bigger because of their six, long, stilt-like legs.
Conlan said there’s an easy way to tell if the bug you’re looking at is a crane fly. If it’s bigger than a dime, he said, then it’s too big to be a mosquito and it’s probably a crane fly. Conlan said among bug experts crane flies are also called “five-legged flies,” because their spindly legs are so fragile it’s hard to find one with all six legs intact.
Whatever you call them, Conlan said people may be seeing more crane flies than they usually do this spring – and lots of other bugs – because we just had our rainiest winter in years.
Few bugs have generated as many myths and misconceptions as the crane fly.
Conlan said here’s what you need to know:
Crane flies are not giant mosquitoes
Conlan said crane flies are related to mosquitoes, but they are not mosquitoes. They don’t bite; they don’t suck blood. In fact, most adult crane flies don’t eat at all. Those that do, Conlan said, drink nectar.
Crane flies can’t transmit disease
They’re not a public health issue like mosquitoes or other vectors, which are the main concern for Conlan and the County’s Department of Environmental Health.
Crane flies do not eat mosquitoes
Nicknames like “mosquito hawks” and “skeeter-eaters” are colorful but totally inaccurate. Their wormlike larvae generally live in wet or moist soil, feeding off decaying organic matter. Some even live underwater. Adult flies don’t live long, about 10 days at the most – unless they’re gobbled up before that by birds, lizards or other creatures.
Conlan said crane flies are actually around all year long, but we notice them more in spring because it’s their peak season, after winter rains create the best breeding conditions for them.
Because their populations are high, and because they’re attracted to lights, this is also the time of year they can often get into houses through open doors and windows. Which can lead unsuspecting people to spontaneously break into the bug dance – that crazy, ducking, hopping, waving your hands around your head dance – that we revert to when trying to shoo away an unexpected critter.
“It’s kind of like the spider dance, only with less finger action as if trying to pull the (spider) webbing off your face,” Conlan said with a chuckle.
Once again, crane flies can’t hurt you. They’re ungainly, but they’re harmless.
But, if they really bug you – pun intended – one thing you can do is turn off your front-door and porch lights, limit your outside lighting or retrofit them with yellow bug lights.
(If your front-porch light is on the same circuit as the lights in front of your house and you want to keep them on, you can just un-screw the front-porch bulb.) That way, fewer crane flies and bugs will be drawn to the light, where they can fly into your house when you open the door to get in.
In any case, Conlan said that because of all the rain we had this winter, this is likely to be a banner year for bugs.
“This is something that people are going to have to kind of expect this year,” he said. “You’re going to see a lot more of these things as the weather warms up.”