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Marsh beetles

Guide to New Zealand's freshwater invertebrates

Marsh beetles ( Scirtidae : Scirtidae )

Larva with long, multi-segment antennae
Larva with long, multi-segment antennae

Diagnostic features

Scirtids are beetles with aquatic larvae and terrestrial adults. The larvae may have an elongated (almost elmid-like) body form, or they can have a wider (cockroach-like) body form. The distinguishing feature of the scirtids is the long, multi-segmented antennae.

Typical habitats

Scirtids can be common in vegetation-covered streams or ponds.

Feeding

Scirtid larvae use comb-like mouthparts to feed on organic detritus on submerged surfaces.

Indicator value

Scirtids can be common in high quality forested streams, but they can also be common in tree-covered urban ponds. Their presence may therefore reflect more about the abundance of leaf litter than any aspects of water quality. They have tolerance values of 8 (hard bottom sites) and 6.4 (soft bottom sites).