#ephemoptera

Mayfly in the SE United States:

Hey there, this is a mayfly, probably in the genus Baetis (called Blue-winged Olives), family Baetidae. I don't know Mayfly ID that well though, so lets ask

Summer is mayfly season on the Upper Mississippi River!

Mayfly nymphs are aquatic insects that swim up from the river bottom and emerge at the surface as their first winged form, called a subimago, during the nighttime. They generally molt into their final adult form, called an imago, the next day. Adult mayflies swarm at dusk to mate and lay their eggs over water. The adults die the following day.

Mayflies are an important food source for many animals. Their abundance is an indicator of water quality. Mayfly swarms can be very large, sometimes even large and dense enough to be detected on weather radar!

These two photographs of adult mayflies were taken the morning of June 5th. The yellow ones, Hexagenia limbata, were found in De Soto, WI. The dusky brown one, Hexagenia bilineata, was found in French Island, WI.

Photo credit: Katie Lieder/USFWS

Mayflies are hatching on the Upper Mississippi River!

This giant mayfly is part of the species Hexagenia limbata and is one of two species you can help report sightings of to the USA National Phenology Network.

Learn more about Mayfly Watch here: https://fws.usanpn.org/Campaigns/MayflyWatch Photo by Jamie Bertram/USFWS.

With arms stocky enough to win a bodybuilding competition, it’s little wonder this burly insect is sometimes called a “muscle mayfly.” But those arms aren’t for heavy lifting, researchers say. Instead, they act like wings. 

At roughly 1 centimeter long, this young Ecdyonurus mayfly lives in fast-flowing river currents, grazing on algae that blankets the rocky riverbed. Rather than sheltering itself from the flow, though, this intrepid insect crawls onto exposed rocks to face the torrent head-on. 

July 11 was a pretty heavy mayfly emergence as seen on local Doppler radar, with variable hatches before and after that date of varying intensity.

Alpena Fish and Wildlife Conservation Office:

Our Aquatic Invasive Species crew had some hitchhikers this week, while sampling in Maumee Bay, Lake Erie. This marks the beginning of the annual mayfly hatch when adults emerge to mate. After hatching they are short lived, where their life span ranges from a few minutes to a couple of days.

*Though the crew was sampling invasive species, this is a native species.

Mayflies (genus Hexagenia) cover the side of a boat house on Lake Erie in Ohio, USA.

Become a Citizen Scientist (North America).

Are you interested in helping us with Mayfly Watch?

It's pretty easy, all you have to do is record data using the app Nature's Notebook when you see mayflies. We will even tell you when to start looking. You can set up your account now so you'll be ready in June to start recording the mayfly emergence.  

https://www.usanpn.org/natures_notebook