Mayflies Swarm Great Lakes Freighter as they Begin Showing Up in Metro Detroit

Published: Tuesday, June 27, 2023 12:00 pm
By: WXYZ Detroit

It's officially Mayfly season. A photo posted by the Interlake Steamship Company shows mayflies swarming a freighter in Toledo.

It happened on the M/V Hon. James L. Oberstar in Toledo, according to the post.

Mayflies have a brief adult life, according to Michigan State University, but will lay 4,000 to 8,000 eggs on the water's surface. those eggs drop to the bottom of the water where they hatch into larvae called naiads.

MSU said the naiads will live underwater for a year or two, and then become wingless in their final immature life stage called subimago. Those subimagos fly toward the shore and within 24 hours, morph into an adult.

Mayfly hatches occur in June or July, but mayflies only thrive in lakes and rivers with good water quality, meaning seeing them is a good thing.