by Jake Vander Zanden
On Mothers Day evening I began receiving a barrage of texts along the lines of ‘What is up with these bugs outside?’ Anyone anywhere near Lake Monona would have undoubtedly noticed these impresive swarms of buzzing insects.
These swarming insects are midges – also known as lakeflies or chironomids. Despite the fact that it is the month of May, they are not mayflies. Midges live anywhere from several months to two years as larvae in the mud on the lake bottom. As larvae they look like tiny red, pink or white worms. Then in May the larvae transform into the adult stage and emerge from the lakes. As adults they generally do not travel far, and within a few hundred meters of the lake they tend to cover the vegetation and everything else.
In the evening midges gather into mighty mating swarms above the trees (see video below), after which the females return to the lake to lay their eggs, and the cycle continues.
Some midges emerge from the Madison lakes every year. But the great Monona Mother’s Day hatch of 2025 is the largest and most impressive midge hatch I’ve observed in my 24 years living in Madison – on par with the infamous midge hatches of Lake Winnebago.
Midge populations are well-known to fluctuate wildly from year to year and many factors affect the size of the hatch. For example, midge populations benefited from the zebra mussel invasion of the Madison Lakes in 2015. Though people tend to view midges as a nuisance, they are a high quality food for migratory birds, bats, fish, and other animals. I certainly do not interpret this year’s mega-hatch as ‘nature out of balance’. So if you happen to be near Lake Monona in the next couple of days, take note of the mighty midge hatch of 2025!