Millions of Mayflies Swarm a Toledo Gas Station — Here’s Why

Quick Take

• The gas station wasn't random. Something about it pulled thousands of mayflies there specifically. Understand their attraction →
• Mayfly swarms look terrifying, but what they signal about your local waterway might actually surprise you. See what swarms signal →
• They won't bite, but a mayfly swarm can still put you in serious danger, and this is especially true behind the wheel. Check the road hazard risks →

Toledo, Ohio, has just experienced a mayfly swarm of Biblical proportions. Thousands congregated at a single gas station, making it nearly impossible to get out of your car. Check out the clip captured a couple of days ago in the Instagram post above. But why are there so many mayflies swarming? What attracted them to the gas station, and how can you get rid of them?

Mayfly Swarms Explained

The location of Toledo provides a clue to what is happening in this clip. It’s situated at the western end of Lake Erie along the Maumee River. Rivers and lakes are home to millions of mayflies. The mayfly life cycle is one of the most fleeting in the natural world. The larvae spend 99 percent of their lives at the bottom of rivers and lakes. After several months or even years, depending on the species, they emerge from the water as winged adults and form swarms. The sole purpose of the swarm is to find a mate. They only live for a few minutes to a few days before they die!

Are Mayfly Swarms Dangerous?

Mayflies do not bite or sting and play an important role in the ecology of their local area. The swarms, however, are so large that they sometimes show up on weather radar! Thousands attach themselves to buildings and other structures. They are attracted to light, which likely explains why so many gathered at this gas station. Even though they won’t harm you, they can make driving dangerous. Large numbers of crushed mayflies can make roads surprisingly slippery, especially after rain. What’s more, they don’t smell very good, so you wouldn’t want them on your clothes or inside your car!

A mayfly swarm is actually a positive occurrence and shows that your local lake or river is healthy. However, it’s a good idea to close doors and windows or use screens to stop them from entering your home. Also, turn off your outside lights and replace any fluorescent bulbs with yellow bulbs, and swap mercury-vapor lamps for high-pressure sodium vapor lamps, as these produce less heat and infrared light that attract bugs. Once they have died, you can simply sweep them up and dispose of them.