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. Our hope is that our neighbors of the river, armed with their mayfly identification, will learn to notice the seasonal changes that occur on the river during the summer.
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 measrues to ensure the public's safety, such as turning off lights on bridges and encouraging drivers to staff off roads inundated with mayflies.
We are seeking observers along the Upper Mississippi River to track the timing of the seasonal event of Mayfly emergence. You can join this effort by learning to identify the two species we are tracking and report at the Mayfly Watch phenology monitoring sites or your own location.
1. Join Nature's Notebook. If you haven't already, create a Nature's Notebook account. See our specifics of observing if you need more details on getting started.
2. Join Mayfly Watch. During registration, check the box next to Mayfly Watch, under USFWS, Region 3 (Midwest) in the Partner Groups list.
If you have already registered a Nature's Notebook account, go to your Observation Deck, click the link to My Account Details, and add yourself to the group.
3. Check your Observation Deck. Under Sites you will be able to switch back and forth between My Sites and Mayfly Watch Sites.
For observations made at one of the Mayfly Watch Sites, be sure you select Mayfly Watch from the dropdown under "Sites" and you will see the sites for the group.
For observations made at your own site, set up your own site under My Sites and add one or both of the mayfly species to your site. Follow these instructions on how to create a site and add animals.
5. Observe mayflies.
Report what you see (yes/no/not sure?) for mayflies following the instructions for mayflies or giant mayflies. You should survey the area within 5-10 ft of where you are standing. You may need to walk around the area, inspecting the vegetation along the shoreline for several minutes.
Remember, mayfly abundance may change hourly - you can report multiple observations in one day by reporting the time at which you made the observation.
|We are interested in observations of these two species of mayfly:|
mayfly, Hexagenia bilineata
giant mayfly, Hexagenia limbata
|brown or black||yellow|
We are interested in the following phenophases for this project. If you observe mayflies, report "yes" to the phenophase that represents the majority of the mayflies you see.
|Phenophase||Definition||H. bilineata||H. limbata|
|Active adults||One or more adults are seen moving about or at rest. Mayfly adults (imagos or "spinners") are brighter in color than subadults, and have clear, glassy wings. (click to enlarge photos)|
|Active subadults||One or more subadults are seen moving about or at rest. Mayfly subadults (subimagos or "duns") are duller in color than adults, and have cloudy wings with a fringe of small hairs. (click to enlarge photos)|
|Dead adults||One or more dead adults are seen, including those found on roads. (click to enlarge photo)|
|Points of contact:|
Erin Posthumus (USA-NPN Liaison to USFWS)
Mark Steingraeber (Fish and Wildlife Conservation Office)
Cindy Samples (Upper Mississippi River NWFR)