Every year, mayflies emerge from the Mississippi River, and the result can be extraordinary! These insects can swarm by the millions during a large emergence — enough to be picked up by weather radar.

Mayflies are an important food source for fish, especially during the summer emergence but also throughout the year when they are in their larval form. Mayflies are also a public safety hazard when they swarm near lights on roads and bridges, as they can pile up and cause roads to be slick and dangerous for cars.

The US Fish & Wildlife Service is interested in tracking the timing of seasonal events like these. In the long term, this citizen science-based research will help educate the public that the presence of these insects is an indicator of generally good local water quality conditions during the past year. Information on the predicted timing of emergence can inform managers when to take measures to ensure the public's safety, such as turning off lights on bridges and encouraging drivers to stay off roads inundated with mayflies.