Water scavenger beetle (Berosus)

Taxonomic group

Hydrophilidae: Berosus

Diagnostic features

Berosus is a hydrophilid beetle with an easily recognised larva that has tentacle-like gills along the abdomen. As in other hydrophilids the larval head is often tipped backwards, and it has long sickle-like jaws. The adults are active swimmers with a generally oval, 5-segmented abdomen. The 7-segmented antennae have three enlarged segments at the tip (but these are often tucked under the head).

[Berosus]. Image: Stephen Moore Image — Berosus. Image: Stephen Moore

[Berosus] larva with abdominal gills. Image: Stephen Moore Image — Berosus larva with abdominal gills. Image: Stephen Moore

Typical habitats

Berosus 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: unassigned; general hydrophilids value 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

Hydrophilids occur in slow flowing waters with moderate to good water quality. The genus has a tolerance value of 5 (hard bottom sites) but there is no soft bottom value (though the family soft bottom value is 8).