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Guide to New Zealand's freshwater invertebrates
Stony cased caddis
Pycnocentrodes caddis larvae construct mobile cases covered in sand grains and small stones. The top of their head is much flatter than other sandy/stony cased genera like Pycnocentria or Pycnocentrella. Pycnocentrodes larvae often attach larger stones or snails to the sides of their case.
Pycnocentrodes larvae are common in streams with stony or gravelly beds, both in bush covered and farmland areas.
They are collector-gatherers feeding on fine organic matter and grazing on streambed algae.
An abundance of Pycnocentrodes larvae indicates at least moderate to good water quality, but many mayfly, stonefly and other caddisfly groups are better indicators of good water quality. They have tolerance values of 5 (hard bottom sites) and 3.8 (soft bottom sites).