Swarms & Infestations
Lake Erie can release billions of mayflies in a single night
Mass mayfly emergences can become so large that radar detects them and shoreline communities wake up to streets and buildings covered in insects.
Video: WTOL11. Embedded from the original YouTube source.
A heavy mayfly emergence can look like a storm made of insects. Clouds rise from the water, drift toward shore, and collect around lights, buildings, sidewalks, and roads.
Scientific radar studies have measured extraordinary numbers during major emergence nights, showing that what looks unbelievable on video can actually involve billions of insects.
The story is especially useful because the same event can be framed as both an urban nuisance and an ecological signal tied to aquatic ecosystem conditions.
What to know
- Large mayfly emergences can be visible on weather radar.
- Adults live only briefly and often accumulate around shoreline lights.
- Healthy mayfly populations are also indicators of improved aquatic conditions in some waterways.
Good questions
What people usually want to know
Why are there so many mayflies around Lake Erie?
Burrowing mayflies develop underwater and can emerge in synchronized seasonal waves, producing enormous short-lived adult populations along the shoreline.
Can mayflies show up on weather radar?
Yes. Very large emergence events have been detected and studied using weather-surveillance radar.