Certain mayfly species have developed adaptations that allow them to take advantage certain environmental niches, especially during the nymph life cycle stage.  In particular, psammophilous mayflies show nymph adaptations for partial or complete burial in the sand (Orwin, 2009).  Burrowing species whose nymphs can sometimes exist in sand tend to inhabit environments with more compact substrata.  A key adaptation that facilitates this preference is very long claws, which are not observed in other species.  These claws allow the nymphs to anchor themselves to grains, sand, or even layers of silt (Orwin, 2009).  They do not always remain in the sand however, another adaptation of the psammophilous species is a streamlined body shape that gives them increased efficiency as swimmers (Orwin, 2009).  Other species of nymph cover their bodies with sand and have little to no claw  Due to water currents that resist the sedimentation of suspended matter, the species that remain partially covered with sand have developed rows of bristles located on the forelegs and mouth parts to help them remain covered.  Another adaptation is observed in Oligoneurisca borysthenica, which have developed tufts of additional gills near the base of their forelimbs and mouth parts for more efficient oxygen exchange while the abdomen is covered by sand (Orwin, 2009).             
An adaptation that is shared by all nymphs that inhabit sandy river bottoms is brightly colored bodies.  Most often the nymphs bodies are light brown with faint marks of darker pigmentation around the abdomen.  These darker marks help the nym's%20Large%20Grey%20Dun.htmphs blend in with their surroundings by imitating darker grains of sand. The rest of the body blends in well with the lighter colored grains of sand, which makes the nymphs visible only when they move.  A unique adaptation pertaining to blending in is observed with the Cercobrachys minutes nymphs.  These are among the smallest of the mayflies and have developed more intensely pigmented regions due to the fact that they often attach to darker lumps of substratum (Orwin, 2009).
    Think these adaptations are interesting?  Visit the interesting facts section to learn about an amazing mayfly phenomenon!


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