INHS Aquatic Entomologist Ed DeWalt told the Peoria Journal Star that the presence of large numbers of mayflies indicates the water quality is high enough to support this species that spends the majority of its life in water. Mayflies emerge from the water this time of year for to live out their short adult life stage—finding a mate and returning to the water to lay eggs. While some people see them as a nuisance, they don't bite and according to Ed DeWalt, "they will make a mess for a week and then they'll be gone."
