Brazos Bend State Park

Pond Life

Water Scavenger Beetles: Family Hydrophilidae

Although as a group, water scavenger beetles are nearly as common as predaceous diving beetles, they are not found in the ponds of Brazos Bend State Park very often. The adults resemble predaceous diving beetles closely. Although their name implies that they are scavengers, they have been known to hunt and kill food.

The larvae of Water Scavenger Beetles are fierce predators. Like the larvae of predaceous diving beetles, they are long and worm-like with huge jaws. Two key differences are that they have spine-like growths on their abdomen, which are absent in water tigers, and their jaws have teeth, while those of water tigers are smooth. Also, while water tigers clamp onto their victims and then suck their insides out, water scavenger beetle larvae swallow their prey whole.

Water scavenger beetle Larva (Hydrophilidae) 13 mm long. The spine-like growths on the abdomen are not clearly visible in this picture.

Jaws of a water scavenger beetle larva showing teeth

Water Scavenger Beetle Larva eating a midge larva

Diptera – True Flies

Predaceous Diving Beetle