They mayflies are here!
This year the mayfly hatch was enough to cause nightmares.
But this isn't a movie, this is just a natural part of nature in the early summer!
What is a mayfly?
A mayfly is a relative of more commonly known bugs like dragonflies, and their life cycle is one of stages. Contrary to popular belief, their lives are a bit longer than five minutes.
Immature mayfly nymphs spend almost their whole lives underwater where they feed on algae or other organic matter at the bottom of lakes and streams. Some feed on the larvae of other insects. But in most cases, the nymphs are down near the bottom of the food chain.
Most people don't even think about these insects until the mayflies hatch into their final stage of life. This often results in a spectacular mayfly swarm. These swarms are often so large, they can be tracked on weather radar by the National Weather Service!
Radar picked up a huge mayfly hatch this evening along the Mississippi River near La Crosse, WI. #gross #bugs #science #KCRGWX
Posted by KCRG-TV9 First Alert Weather on Saturday, July 28, 2018
The mayfly "hatch" is the insects entering the final stage of their life cycle. The nymphs molt their skin and enter what is known as the subimago (subadult) stage after they emerge from the water surface.
The subimago mayflies then molt one final time and enter the final stage of their life known as the imago stage. Depending on the mayfly species, this final molting occurs anywhere from a few days to a few hours after they entered the subimago stage. Either way, the mayfly doesn't live for much longer after leaving the nymph stage.
The insects only live long enough to mate and lay their eggs back into lakes and streams, and then they die.
Heavy hatch in 2019
This year has been an especially heavy mayfly hatch for much of the Midwestern United States and parts of Canada. It didn't take long for photos and videos of the bugs swarming homes, vehicles and other places to start hitting social media channels.
Cleveland, Ohio was especially hard hit a few weeks ago. Photos of a car parked under a white street light went wildly viral as the mayflies completely covered it.
You saw them on radar last night... here's what they looked like morning. Ummm.... yikes? Mayflies. pic.twitter.com/WTgTroqBKf
— Jason Nicholas (@JasonNweather) June 27, 2019
In other areas, meteorologists shared radar images of the clouds of flies emerging from the Great Lakes. The cloud appears on radar as a green cloud like an approaching thunderstorm over Lake Erie.
— Jason Nicholas (@JasonNweather) June 29, 2019
— NWS Cleveland (@NWSCLE) July 2, 2019
Parts of Michigan and Wisconsin also experienced a heavy hatch this year, and we might see more of in the coming weeks.
Oh my goodness! Glad to know our water must be really clean! Mayflies, June Bugs, Fishflies...whatever they are, it was nice while they stayed away! A new mascot for the @ForestGladeBL? Forest Glade Fishflies?!? pic.twitter.com/oCxV0o7SzV
— Beth Adlam (@BethAdlam) July 9, 2019
Have you ever heard the word ‘hatch’ and thought WTF is a ‘hatch’? Well, this is a hatch. Mayflies (I believe...), on Washington Island, WI last week. /1 pic.twitter.com/i62BPVEKk8
— Tim Low (@tlow) July 10, 2019
In the past, some hatches have been so heavy they've caused road closures and vehicle damage.
While most people looked at these images and videos and were repulsed by the horror of it, you really shouldn't be. In fact, most biologists and entomologists were thrilled to see a heavy hatch.
That's because mayfly nymphs are highly susceptible to the negative effects of pollution in a lake or stream. A heavy swarm of mayflies over Lake Erie is an indication that the lake water quality is good right now.
Now is the time to go fishing!
Fly fishermen are celebrating because a mayfly hatch means the fishing is predictable, and damn good. Now is the time to start throwing flies that resemble the adult and subadult stages of mayfly. There are literally billions of mayflies entering the final stage of their life cycle right now.
Many of these flies are going to end up in the bellies of fish and other predators who can't resist a free and easy meal. If you have mayflies swarming in your area right now, you'd best get down to the water with a fly rod in hand as soon as possible because a fishing opportunity like this doesn't come along every day!