Weather Watch

What are those spindly legged insects invading your home?

Often called mosquito hawks or skeeter eaters, these delicate creatures pulsating off your walls and ceilings are adult crane flies.
Often called mosquito hawks or skeeter eaters, these delicate creatures pulsating off your walls and ceilings are adult crane flies. Wikimedia Commons

They are 1-inch-long gawky creatures with skinny abdomens, extremely long, thin legs and big compound eyes that let them see in an almost 360-degree range.

They are attracted to light like moths and, at this time of the year, they often fly through an open door or window and into your home after sunset.

Often called mosquito hawks or skeeter eaters, these delicate creatures pulsating off your walls and ceilings are adult crane flies.

Despite the nickname, they don’t eat mosquitoes — or much of anything else, for that matter. They just don’t have the mouth parts for it.

A crane fly spends most of its life as larva and then lives one or two weeks in its final long-legged stage of life. Just enough time to mate and lay eggs.

California is home to about 400 types of the about 15,000 types of crane flies throughout the world. They all belong to the Tipulidae family and more or less resemble mosquitoes. The largest can have leg spans over 10 inches.

Adult crane flies can be seen along the Central Coast for much of the year because of our mild climate, but they are most common between March and June. Reports from around the Central Coast and the rest of California indicate that this spring has seen a bumper crop of crane flies.

“We seem to have tons of crane flies around our house,” Kristin Inman of San Luis Obispo told me.

And George Dunnigan of Santa Margarita said, “We left our back door open the other night for about 10 minutes, and we had about 20 of them flying around our kitchen.”

The increased amount of crane flies this year is probably because of the current El Niño event combined with global warming.

Historically in January through March, the average low temperature in San Luis Obispo is 42.4 degrees. So far this year, the average is 47.7 degrees, more than 5 degrees warmer than normal. Not only were the temperatures warmer, but we received the most rain since the 2010-2011 rain season. This increased amount of warmth and moisture is vital for the insect’s life cycle. After mating, the female seeks soggy soil with plenty of decaying vegetation to lay her eggs. Other types of crane flies lay their eggs in creeks and ponds.

Depending upon soil temperature and moisture — the warmer and wetter the better — the larvae can quickly hatch and are referred to as “leather jackets” because of their tough brown outer cuticle. Unlike their parents, the larvae devour just about anything they can find below the soil by day and on the surface by night. The larval stage can last a month or more before they transform into adult crane flies.

For most, having these critters flying around the house isn’t at all desirable, especially when they lose legs or wings but keep trucking along like a zombie apocalypse. The latest guidance from the National Oceanic and Atmospheric Administration’s Climate Prediction Center and other long-range forecast centers indicate warmer and wetter conditions will continue into May. That could mean even greater numbers of crane flies later this spring.

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Celebrate Earth Day on April 16 by joining PG&E employees for a work project at Montaña de Oro State Park. The event is one of a number of service projects sponsored by PG&E and the California State Parks Foundation. Be sure to dress for outdoor work with long pants, long-sleeved shirt, sturdy shoes, hat, gloves and sunscreen. Snacks and a light lunch will be provided. Bring your own refillable water bottle. Rangers will provide tools and supervision. Please register at the California State Parks website, www.calparks.org/help/earth-day/earth-day-registration.html

John Lindsey’s column is special to The Tribune. He is PG&E’s Diablo Canyon marine meteorologist and a media relations representative. Email him at pgeweather@pge.com or follow him on Twitter @PGE_John.

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