What is causing this unusual concentration of dragonflies?

Asked September 4, 2015, 11:52 PM EDT

On Thursday, September 3, around 7:30 p.m., while driving in the country in Greene County (Cortsville Road, Cedarville Twp) for about a mile, I saw many, many (hundreds?) of what looked like dragonflies. Is this a type of migration? Where do they go? It was pretty amazing.

Greene County Ohio dragonflies

1 Response

We have had several observations of dragonfly swarms across the state. While there are some species that migrate, this is not a normal case for Ohio dragonflies. It appears that we are seeing the success of nymphal development, likely due to the abundant rainfall earlier in the season that extended the area that ponds, lakes, and streams occupied. Dragonflies will often accumulate over fields and open areas where there are plenty of small flying insects (often midges and mosquitoes). These insects are also in abundance this year because of the earlier rains.