Stonefly (Taraperla)

Taxonomic group

Gripopterygidae: Taraperla

Diagnostic features

Taraperla stonefly nymphs are relatively small, with a rosette of anal gills between the cerci (“tails”). The posterior edges of the thoracic segments are extended to form lobes or spines (depending on the species).

[Taraperla]. Lobes on thoracic segments. Image: Stephen Moore Image — Taraperla. Lobes on thoracic segments. Image: Stephen Moore

[Taraperla]. Spines on thoracic segments. Image: Stephen Moore Image — Taraperla. Spines on thoracic segments. Image: Stephen Moore

Typical habitats

Taraperla nymphs can be found in cold water stony streams, both above and below the water surface.

Feeding

They are thought to be “collector-gatherers”, feeding on a range of organic matter accumulating on stream beds.

Indicator value

Hard bottom: 7
Soft bottom: 8.3

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

Taraperla nymphs are usually found in streams with good water quality, though they are rarely found in abundance. They have tolerance values of 7 (hard bottom sites) and 8.3 (soft bottom sites).