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Mayfly nymphs are always aquatic, but their specfic habitat depends on the species.

• Each species survives best in an environment with a specific substrate, depth, oxygen level and amount of wave action.
• Generally, mayfly nymphs tend to live in streams, but some can also be found in still waters.
• They are most common in waters that are cool, clean and shallow, such as shallow streams and at the edges of lakes near the shore. 
• They like to burrow into the substrate in areas with sediment deposits, and may have a specific preference of substrate particle size or aquatic plant depending on the species.

LIFE CYCLE 
Mayflies undergo incomplete metamorphosis as they do not have a puapl stage. This involves passing through 3 life stages which are egg, nymph and adult.

Eggs

• After mating, the female mayfly lays her eggs by dipping them into the water while flying, releasing a few eggs with each dip.
• Another technique is to deposit the eggs on the surface of lakes and streams, where they sink and scatter among aquatic plants and debris.

Nymphs

• Mayfly nymphs emerge shortly after the eggs have been laid.
• The new hatchlings are less than 1 mm long and have no gills, bearing little resemblance to the adults they will become.
• Throughout their development, the mayfly nymphs can grow up to 3 cm long, passing through many stages of development (called instars).
• The number of instars (stages of development) depends on the species, but can range anywhere from 12 to 45, however most have about 15 to 25. 
• The nymphs live in the water, along the bottoms of freshwater habitats where they can take shelter in the substrate. 
• As nymphs become older, they develop gills, and some signs of their gender can be seen in the last few stages before adulthood.
• The length of the nymph stage varies depending on the species of mayfly, along with the water temperature and the geographic location.
• The nymph sheds its outer layer (called 'molting') by emptying its guts and filling its mid-section with air while floating up to the surface of the water at the same time. When it gets to the top, its outer layer splits open and the wings come out.
• After a very vulnerable period during which the subimago is soft and too weak to fly, it gains some strength and then flies from the surface of the water to a more sheltered place, like a tree or among tall grass.
• It stays sheltered and rests until its final molt, which occurs within 24 to 48 hours, leading to the final stage of the mayfly, called the 'imago'.

Product Code: MAYSIZFX38