Mayflies

Mayflies go by a lot of different names. They are called sandflies, drakes, shadflies, dayflies, and fishflies. They also go through four different stages, starting out as eggs and ending in the adult winged form that people identify with mayflies.

 

As nymphs (the second stage of their cycle), mayflies are aquatic. They actually have gills at this stage and are slender with six clawed legs. They are very small- some only 2.55mm (which is 0.1 inches long). The biggest of the nymph varieties can get to 32mm, which is just a little more than an inch.

 

Usually, eggs hatch into nymphs within a few weeks but the nymphal stage can last as long as two years. While it can also happen quickly, in as little as two weeks, it usually occurs on an annual cycle.

 

Once they develop into adulthood, their wings will emerge and they will leave the water to rest and shed their skin for the last time. This third phase can last minutes or up to a few days. At this point, mayflies will have opaque wings- in general, a large triangular pair and a smaller rounder pair behind. They have two or three tails that are as long or longer than their bodies, which are long, thin and brown, gray or yellow.

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For even more information about mayflies in Virginia, check out our blog post