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Swimming mayfly (Nesameletus)

Taxonomic group

Nesameletidae: Nesameletus

Diagnostic features

Nesameletus mayfly nymphs have a torpedo-like body form, fringed caudal filaments (“tails”), short antennae and single leaf-like abdominal gills.

Typical habitats

Nesameletus larvae are most common in pools in stony or gravelly, bush covered streams.


Nesameletus larvae feed on biofilm (algae and other microorganisms) and plant detritus on the streambed.

Indicator value

  • Hard bottom: 9
  • Soft bottom: 8.6

The tolerance values (ranging from 0 to 10) give an indication of which are the sensitive taxa (values of 8 or more) and which are the tolerant taxa (values of 3 or less). For more information see: Indicator species

Abundances of Nesameletus suggest good habitat and water quality conditions, especially if other mayfly or stonefly groups are abundant. They have tolerance values of 9 (hard bottom sites) and 8.6 (soft bottom sites).