Water scavenger beetle (Hydrophilidae)

Taxonomic group

Family: Hydrophilidae

Diagnostic features

Hydrophilid beetles (or water scavenger beetles) have larvae with soft abdomens that may be covered in bumps or long gills (see Berosus) depending on the genus. The larval head often appears tipped backwards, and long sickle-like jaws are often visible. The adults are active swimmers and generally oval in outline. The antennae have three enlarged segments at the tip (forming a “club”), but often the segmented palps (mouthparts) extend in front of the antennae.

Water scavenger beetle (Hydrophilidae) adult with 3 enlarged antennal segments. Image: Stephen Moore Image — Water scavenger beetle (Hydrophilidae) adult with 3 enlarged antennal segments. Image: Stephen Moore

Water scavenger beetle (Hydrophilidae) larva. Larval head often tipped backwards. Image: Stephen Moore Image — Water scavenger beetle (Hydrophilidae) larva. Larval head often tipped backwards. Image: Stephen Moore

Typical habitats

Hydrophilids can be found in weedy and stony, streams and ponds.

Feeding

The larval mouthparts suggest they are predators, but the adults may also scavenge on streambed detritus.

Indicator value

Hard bottom: 5
Soft bottom: 8.0

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

Hydrophilids occur in slow flowing waters with moderate to good water quality. They have tolerance values of 5 (hard bottom sites) and 8.0 (soft bottom sites).