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Sandfly or black fly

Guide to New Zealand's freshwater invertebrates

Sandfly or black fly ( Simuliidae : Austrosimulium )

Bulbous abdomen
Head with filter feeding fan

Diagnostic features

Austrosimulium is a member of the simuliid blackfly (commonly called “sandfly”) family. They have small larvae characterised by a bulbous abdomen and a head bearing filter-feeding fans. The larvae use small hooks at the end of the abdomen to attach to submerged surfaces, while the filter-feeding fans are extended to face the current.

Typical habitats

Austrosimulium larvae are found in fast and slow flowing, hard bottom and soft bottom streams in bush covered, farmland and urban areas.

Feeding

Austrosimulium larvae are filter feeders using their fan of setae to collect drifting fine particulate organic matter.

Indicator value

Austrosimulium larvae can be abundant in pristine streams, but also in poor quality urban streams. They have low tolerance values of 3 (hard bottom sites) and 3.9 (soft bottom sites).