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Stonefly (Megaleptoperla)

Taxonomic group

Gripopterygidae: Megaleptoperla

Diagnostic features

Megaleptoperla stonefly nymphs are larger than most aquatic insects. They have a rosette of anal gills between the cerci (“tails”). Underneath the anal gills are “subanal lobes” that have distinct spines pointing posteriorly.

Typical habitats

Megaleptoperla nymphs are common in many bush covered, cold water, stony streams, and sometimes weedy streams.


They may feed on a range of organic matter accumulating on stream beds. We have observed one feeding on a midge larva.

Indicator value

  • Hard bottom: 9
  • Soft bottom: 7.3

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

Megaleptoperla nymphs are only likely to be common or abundant in streams with good habitat and water quality. They have tolerance values of 9 (hard bottom sites) and 7.3 (soft bottom sites).