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Guide to New Zealand's freshwater invertebrates
Spiral cased caddis
Rakiura caddis larvae construct a small mobile case made of sand grains arranged in a spiral. Unlike the related Helicopsyche, Rakiura has a chimney-like upward extension from the middle of the case.
Rakiura larvae are common in some bush-covered streams in the South Island.
They are likely to be “collector-gatherers” (as are Helicopsyche), feeding on a range of organic matter accumulating on stream beds.
Rakiura larvae are generally found in streams with good habitat and water quality, hence the maximum tolerance value of 10 for hard bottom sites (there is no soft bottom tolerance value).