A thick, massive band of mayflies traveling along the Mississippi River created a swarm so thick it became visible on the National Weather Service radars on July 20, 2014. From there, the image goes viral as people watch from all over, the largest of swarm of bugs they have have ever seen.
Mating season this summer is creating a mass buzz in the upper Mississippi River Valley.
Sunday evening, wary Wisconsinites near La Crosse crawled for cover, while others caught the swarm of flies on camera. The bugs even appeared on the weather radar as they emanated from the river bottom to mate, breed and spread. (Yellow indicates a higher concentration of energy.) -Yahoo
As terrible as these hatching events sound, it’s actually good news. The recent surge of these mayflies have many in the Department of Natural Resources applauding because the amount of mayflies seen often correlates to how healthy area lakes and rivers are. With the huge influx in pollutants during the latter half of the 20th Century, mayflies nearly became extinct because their larva are especially sensitive to pollutants in the water like lead, mercury, and many pesticides. But since humans have learned how harmful these can be, the slow cutting back of these has allowed the waterways to become cleaner in recent years and has allowed the mayflies to flourish once again.
-Boing Boing
Source: http://www.crh.noaa.gov/arx/?n=mayflygeneral#July202014
http://www.accuweather.com/en/weather-news/mayflies-swarm-mississippi-riv/30937631
http://boingboing.net/2014/07/21/hordes-of-mayflies-explode-in.html