Head to head
Great Silver Water Beetle vs Great Diving Beetle
Great Silver Water Beetle
VS Great Diving Beetle
The great silver water beetle and the great diving beetle are the two giants among the water beetles of European ponds, and they are easy to mix up at first glance.
| Great Silver Water Beetle | Great Diving Beetle | |
|---|---|---|
| Scientific name | Hydrophilus piceus | Dytiscus marginalis |
| Relationship | A large water beetle of still, weedy ponds | A large water beetle of still, weedy ponds |
| Size | A glossy black, oval body that can reach about 4 to 5 cm long | A streamlined body about 3 cm long, dark olive-brown with a yellow border around the thorax and wing cases |
| Adult diet | Mainly water plants and algae | An aggressive predator of tadpoles, newt larvae, small fish, worms, snails, insect larvae, and other beetles |
| Larvae | Fat, curved, predatory larvae that eat water snails by chewing a hole in the shell | The water tiger larva is a long, pale, fast-moving hunter up to 6 cm with hollow sickle jaws |
| Breathing | Carries a film of air against its underside that looks like silver, renewed by lifting its antennae to the surface | Surfaces tail-first and traps a bubble of air beneath its hardened wing cases |
| Eggs and flight | The female spins a floating silk egg case with a thin mast that lets air in, and the beetle can fly at night | On warm nights it leaves the water and flies to find new habitat, sometimes crash-landing on wet roads |
| Conservation status | Not Evaluated, and rare or declining in places as clean, weedy ponds are lost | Least Concern, across Europe and temperate northern Asia |
Great Silver Water Beetle vs Great Diving Beetle: common questions
Which one is a vegetarian?
The adult great silver water beetle eats mainly water plants and algae, whereas the great diving beetle is an aggressive predator.
How does each breathe under water?
The silver water beetle carries a film of air on its underside, while the diving beetle traps a bubble of air beneath its wing cases.
Which one has a floating egg case?
The great silver water beetle, whose female spins a silk case with a thin mast that lets air reach the eggs.