By Sarah Barney, featured image from Brian Alford
Most people dread mayfly season, the season of slippery roads, clogged gutters, and the constant smell of dead fish. It’s undeniable that they take over the Lake Erie coast and the islands for a few weeks in June, but they are crucial for a healthy ecosystem and sharing nutrients. To understand their importance, you must first understand their extremely short lifecycle.
The mayfly starts its life at the bottom of the lake. The female lays the eggs in still water, and they will either settle to substrate or attach to a submerged rock. The eggs are small and round, depending on the species. Females can produce less than 50 eggs or more than 10,000 eggs. After around two weeks, the eggs hatch entering the second stage.
Once the egg hatches, the mayfly becomes a nymph. They can spend up to two years at the bottom of the lake, but the average is a year. During this time, they molt up to 50 times as they keep growing. They eventually find their way to the surface of the lake and emerge as the next stage.
As they move from the water to the air, the skin on their back splits down the middle to make room for their wings. They fly to find terrestrial shelter, and molt one last time to bring them into the final, adult stage, the Imago. Mayflies are the only insect that molts after growing wings.
The only purpose of an adult is to mate. At dusk, the males fly up and down and side to side repeatedly over the lake, waiting for the females to join. Eventually, the males will approach the females and mating begins. After, the male flies off and dies, and the female releases the eggs and dies.
Mayflies are a vital link in the freshwater food web. They are loved by fish, frogs, birds, turtles, and snails. Because they are bottom dwellers for most of their life, they bring necessary nutrients from the bottom of the lake to the surface as they become an adult. The animals that eat the adult mayflies get nutrients they have little access to. Furthermore, when mayflies die, they provide energy and nutrients to algae and other aquatic plants.
Along with being important for our Lake Erie ecosystem, mayflies are just plain cool. They are ancient insects; first evolving 100,000 years before dinosaurs. They are so old that they are the only insect that has two stages of adulthood. And they are used for monitoring water quality in the lake. Their presence (or lack thereof) is an indicator of the health and diversity of the lake.
To help destroy the stigma and celebrate mayfly season, the Nature and Wildlife Center is sponsoring the Eat a Mayfly Challenge. For this, tag us in a video of you eating a mayfly on Facebook, TikTok, or Instagram with the hashtag #EataMayfly. We would love to see you try!
Sources and Further Reading
The Mayfly Life Cycle by the Tweed Foundation
Basis/Purpose - Mayflies of North America by Purdue University
Mayfly by Britannica