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Taxonomic group

Dytiscidae: Liodessus

Diagnostic features

Liodessus is one of the dytiscid “diving beetles” having larvae and adults that are active swimmers. The larvae have a short cone-like “nose”, and two tail “cerci” that have long side hairs. The adults are tiny (up to 3mm), oval, with 11-segmented antennae, and with obvious grooves linking the wing covers (elytra) and the thorax.

Typical habitats

Liodessus are most common in ponds, wetlands and slow-flowing weedy streams.


The dytiscid beetles are predators, feeding on other pond invertebrates.

Indicator value

  • Hard bottom: 5
  • Soft bottom: 4.9

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

The presence of Liodessus is more likely to reflect pond-like habitat conditions rather than any particular water quality conditions. They have medium tolerance values of 5 (hard bottom sites) and 4.9 (soft bottom sites).