Great silver water beetle
Hydrophilus piceus
— Where the name comes from
Hydrophilus is “water-lover”, from hýdōr and phílos. Piceus is Latin for “pitch-coloured”, glossy black as a caulker’s pitch. It is a plain descriptive name, and gives no hint of the animal’s oddity: that the adult, of this water it loves so much, is nearly vegetarian, while the larva living beside it is among the fiercest predators in a pond.
— Facts
- Group
- Insects · Insecta
- Order
- Beetles
- Habitat
- Ponds, canals and ditches rich in vegetation
- Range
- Europe, western Asia, North Africa
- Size
- 34–48 mm, among the largest European water beetles
- Diet
- Algae and water plants as an adult; snails and tadpoles as a larva
- Lifespan
- 1–2 years
— Characteristics
- 01
It breathes air stored in a silvery pile beneath the body.
- 02
It renews its air supply with its antennae, not with its tail.
- 03
It swims moving its legs alternately, not in simultaneous strokes.
— What sets it apart
It carries its atmosphere with it. Beneath the body it has a very dense pile that holds a film of air: underwater it looks plated with silver, and that reserve is what lets it stay submerged. To renew it, it does not surface tail-first like the diving beetles but comes up head-first and uses its antennae as a tube, opening a channel between the surface and the ventral bubble. The female also builds a floating silk cocoon for her eggs, fitted with a vertical chimney that projects above the water and keeps them aired: a raft with a funnel.
