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Taxonomic group

Leptoceridae: Oecetis

Diagnostic features

Oecetis caddis larvae construct delicate mobile cases made of sand grains. They have a pale head with dark speckles, and their hind legs have long, curved claws. Like other leptocerids their hind legs are much longer than their fore legs.

Typical habitats

Oecetis larvae are common in many slow-flowing streams and rivers with sandy beds.


They are predators, preying on other small stream invertebrates.

Indicator value

  • Hard bottom: 6
  • Soft bottom: 6.8

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

Oecetis larvae are found in streams of moderate to good water quality so they are not necessarily an indicator of pristine conditions. They have tolerance values of 6 (hard bottom sites) and 6.8 (soft bottom sites).