Invertebrates
Great Silver Water Beetle
Hydrophilus piceus
Among the weed of a quiet pond, a great silver water beetle rises to the surface, its black body gleaming and its underside plated with silvery air.
Overview
The great silver water beetle, Hydrophilus piceus, is a glossy black giant among the water beetles of Europe, North Africa, and western Asia. Its silvery air film, floating egg case, and snail-eating larvae make it one of the most unusual insects of still water.
A beetle with a floating nursery
The silk case that the female spins is a tiny boat with a mast that lets air reach the eggs, protecting them from predators and keeping them dry.
Status
Not Evaluated, and declining in places.
Great Silver Water Beetle: common questions
Why is it called the silver water beetle?
It carries a film of air against its underside, which looks like silver under water.
What is unusual about its eggs?
The female spins a silk case with a thin mast that sticks above the water, which lets air in, and the case floats like a small boat.
What do the larvae eat?
They are predatory and eat water snails by chewing a hole in the shell.
Where is the great silver water beetle found?
It lives in still, weedy ponds, ditches, and pools across Europe, North Africa, and western Asia.