September 17, 2014

Medina
Partly cloudy
44°F

As summer returns, so do the mayflies

Towns on the lake know this time of year well. It’s when mayflies emerge from the lake and surround buildings, houses and, especially, bright lights outside of restaurants and bars.

In the past few weeks, the largely seasonal insects have been coming out in full force as a result of the early summer mating season.

Though it may not seem like it, lakeside residents actually are seeing fewer numbers of the largely seasonal insect than they would have 10 years ago.

“We’ve had a reduction of mayfly issues,” Dave Shetlar, professor of urban landscape entomology at the Ohio State University said.

Adult mayflies live less than two days and peak in numbers around the end of June, but fewer mayflies have been coming to northern Ohio each year due to growing populations of zebra mussels in Lake Erie. The zebra mussel is an invasive freshwater mussel that “cleans up” the algae at the bottom of the lake, which mayflies generally eat, Shetlar said.

The result is that many mayflies that would have gone to the bottom of Lake Erie to feed are now finding new areas in the smaller wetland habitats along the shoreline.

Though the number of mayflies continues to decrease each year, it may be difficult for northern Ohio residents to notice, especially around the lake.

Shetlar said most longtime Ohio residents are used to the insects and that the insects don’t pose a threat to humans besides an “annoyance factor.”

That annoyance can be troublesome for businesses, however. Shetlar said many adult mayflies are attracted to bright lights — especially those outside of bars and restaurants.

“They can’t escape from the light and they die there,” he said, adding that restaurant owners have been know to sweep — even shovel — clumps of dead mayflies from their porches.

Despite the annoyance, Shetlar said there is no reason to try to kill the mayflies, which smell when killed, because they only live for a few days and only will be around northern Ohio for a couple of weeks.

“They’re going to die anyway,” he said.

Contact reporter Anna Merriman at (440) 329-7245 or amerriman@chroniclet.com.