Guest blog by C. Newsome.
Mayflies can be found all over the state of Ohio, but the largest numbers are found close to Lake Erie. Throughout June, large numbers of mayflies enter their final adult life stage and begin to swarm. In locations like Port Clinton, the mayfly swarms can blanket cars, roads, and houses. These swarms grow so large they can even be picked up on weather surveillance radar!
Caption: This video is an example of a mayfly hatch being picked up on weather surveillance radar over Lake Erie
So far, while sorting volunteer kits, only a small number of mayflies have been captured in the bowl traps. It is surprising that traps set in northern counties, specifically counties around Lake Erie, have not captured more mayflies in June. The mayflies can come in waves so thick they can be shoveled like drifts of snow.
Caption: Sensationalized news clips of a massive mayfly hatch
Adult mayfly photographed by MaLisa Spring
Immature mayfly in a stream photographed by MaLisa Spring
Caption: Image of mayfly and mayfly larvae captured by MaLisa Spring.
It is both fascinating and frightening to see plague-like numbers of mayflies but that is only a small portion of the mayfly life cycle. After hatching, most of the mayfly life cycle consists of various nymph forms. At this stage immature mayflies dwell at the bottom of lakes, rivers, and streams. They mainly feed on algae and leaf later until they reach the subimago stage. The immature mayflies undergo multiple molts where there is eventually a transition to a subimago, and finally to an adult or imago stage. After mayflies reach adulthood, they no longer eat due to their lack of functioning mouthparts. The subimago stage is a brief stage where the mayfly has functional wings but molts one last time. This final molt brings on the imago stage where mayflies swarm, mate, lay eggs, and die. As adults their primary goal is to quickly mate before death. The aftermath of the swarming is not only disturbing but smelly! The piles of dead bugs do not always go to waste. The city of Port Clinton has a mayfly compost site for these insects!
The large swarms are a good sign for Lake Erie. The size of the swarms is one way the health of the freshwater ecosystem can be measured. Mayflies are very sensitive to water quality changes and only thrive in clean, healthy ecosystems (Stepanian et al). If there is a decline in the overall size of mayfly hatches, the lakes water quality could be in decline. The mayfly hatches are also an important food source for other freshwater organisms, especially fish. As a fisherman, I personally have seen the shift in walleye feeding patterns that occur during mayfly hatches. The hatches are a great food source for hungry summer walleye, however they can gorge themselves and become so full they are harder for fisherman to catch!
Information about mayflies is from Stepanian et al. (2020) and Arghavan Salles (2000)
More information can be found at:
Salles, Arghavan. Ephemeroptera Mayflies.
https://ucmp.berkeley.edu/arthropoda/uniramia/ephemeroptera.html. Accessed 14 July 2021.
Stepanian, Phillip M., et al. “Declines in an Abundant Aquatic Insect, the Burrowing Mayfly, across Major North American Waterways.” Proceedings of the National Academy of Sciences, vol. 117, no. 6, Feb. 2020, pp. 2987–92.
A Short Update from MaLisa:
We sorted 8 kits last week: L. Mautz (Morgan), L. Dillon (Madison), D. Kadonaga (Franklin), N. Ganson (Shelby), L. Moore (Trumbull), A. Blyth (Hocking), P. Zelenik (Mahoning), and R. Bowell (Miami).
That brings us to 138 kits sorted and we are now over 50,000 bees pinned! We should finish sorting the kits we have left this week and I am starting students on identification. If you still have your samples from 2020 and want them processed and identified, please get them turned in ASAP.
Mystery body part answer:
Several people got close with the mystery image from last week!
What could this be? I’ll give you a hint: it is part of an insect 😉
The answer is that the structure is the ovipositor (egg laying apparatus) on a restless bush cricket!
Crickets often have long ovipositors that they use to lay eggs into vegetation. The ovipositor is the long thing structure on the right side of the insect in the photo here.
All for now,
MaLisa
Congratulations on getting all the kits pinned MaLisa!
We haven’t finished sorting and pinning yet! We are close though, so we are almost there. Also, there are a few kits that have not yet been turned in, so depending on if/when those get turned in, that will impact our ability to get them pinned quickly. We will lose many of our student workers in a few weeks, with greatly reducing their hours once school starts back up, so we are cutting it close.
That car with the mayflies belongs to a friend of mine from Middle Bass. I think I had some of the mayflies in my cups last summer. I was surprised that they didn’t get out. Always enjoy reading your posts!
I am pretty sure your kit did have the most mayflies of all the kits. Or at least there were a few mayflies in yours, especially in early june. It didn’t stop the bees from still finding the cups though!