Mayflies

Habits

As mayflies are primarily an aquatic species, they spend most of their lives developing in the water. They are common around freshwater sources such as streams, lakes or ponds. Mayflies are often seen as a sign of healthy water ecosystems because they are very sensitive to pollutants. They have relatively short lifecycles. Females lay their eggs while flying low over the water or in the water directly, preferring clean, fresh water. Once the eggs hatch, these nymphs live near the bottom of the water, feeding on organic material. During this time as immature insects, fish and other insects will eat these nymphs. Once they mature, mayflies will leave the water, spending a day or two drying off and shedding their skin before flying away to mate. Males die after mating while females die after laying their eggs. 

Mayflies are attracted to light and can become a nuisance when they gather at night near doorways or around lights, sometimes in large numbers. 

What do mayflies eat?

Immature mayflies, also known as nymphs, feed on microscopic algae and organic matter in the water. Adults don’t have functioning mouthparts, and therefore do not eat. However, this isn’t an issue since mayflies only live as mature adults for a few days.  

Threats

Mayflies are nuisance pests and cannot bite or sting. They are, however, very attracted to light, which can result in massive swarms around buildings at night and piles of dead flies below lights and windows in the morning. In areas that see large swarms, mayflies could affect driving conditions and visibility. 

For allergy sufferers, mayflies could be a source of seasonal allergies. When they die, their molted skin and bodies break up and are easily carried by the wind.