BBC "Swarm Chaser" seeking big mayfly hatch in Wisconsin - WXOW News 19 La Crosse, WI – News, Weather and Sports |

BBC "Swarm Chaser" seeking big mayfly hatch in Wisconsin

LA CROSSE, Wisconsin (WXOW) - Each summer, massive swarms of adult mayflies hatch from the Mississippi River.

They're a nuisance to some, but a spectacle to others.

The mayflies have attracted the attention of entomologist and television host Dr. George McGavin.

A crew for the upcoming BBC program "Swarm Chaser" arrived in Wisconsin Friday. The program will feature McGavin in the "eye of the swarm" for a variety of animal species. 

"Earlier in the week we were filming bees. I was completely covered in bees," McGavin said. "The other day I was hanging off a rope in a cave near Austin in Texas, and there were ten million bats flying around me."

McGavin is hoping for a similar situation with a mayfly hatch. He first became interested in the insects when he saw a photo of a man shoveling them to clear a path for his car. In Wisconsin, swarms can be large enough to show up on Doppler radar. Some years, road crews have cleared the bugs from the road with snowplows.

McGavin says the recent heat wave could mean a larger hatch than the one in June. He explained why the insects swarm in such large numbers. 

"Those swarms that you see are swarms of males flying around, into which females will enter and mate," he said. "And, of course, if you do that en masse, it means A: Your chance of finding a mate is very much higher, but also, your chances of surviving to lay eggs is also very much higher. "

Mayfly hatches occur in England and Hungary, but not to the magnitude Wisconsites see. McGavin credits the Mississippi River, and says the mayflies play an integral role in the river ecosystem.

"Insects form a really essential part of the food chain for lots of fish and birds. And the fact that they have this interesting swarming behavior is in itself interesting," he said.

McGavin is hoping you can help him track the next big mayfly swarm. If you see one developing call 608-790-7012 to report it.

"Swarm Chaser" will be out on the BBC and Discovery Channel sometime next summer.

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