Mayfly hatch near La Crosse shows up on radar

By Zachary Knapp

MINNEAPOLIS -- July is here and, unfortunately, so are the mayflies.

These harmless but irritating insects have made their return in full force, and due to their incredible numbers, could even be seen on radar as they hatched near La Crosse, Wisconsin.

According to the Minnesota Department of Natural Resources, mayflies spend 99% of their lives as larvae living in the sediment of freshwater systems like the Mississippi River.

DNR research scientist Gary Montz says that the hatching phenomenon in the Mississippi River occurs as the burrowing mayflies emerge all at once to mate, lay eggs, and then die.

The amount of mayflies that hatch and swarm can sometimes be overwhelming. In the past, mayflies have blanketed streets and walls of the Twin Cities with a thick, buggy layer.

Although mayflies can be irritating due to their sheer numbers, it's in everyone's best interest if they stick around. The DNR says that mayflies are extremely important in the aquatic food web, and are fed upon by other invertebrates, amphibians, reptiles, fish, birds, and mammals.

Additionally, Montz explains that swarming mayflies is a good sign since it means that the river is healthy enough to support the mayflies in their underwater burrows.

Still, though, no one likes to find their car covered in thousands of bugs. 

In:
• Wisconsin