This spider builds a silken retreat under water among plants which it fills with air. It is a good swimmer and will catch its aquatic prey and subdue it with its venomous jaws.

Life span
Water spiders live for about two years.

Statistics
A water spider's body length is 8-15mm.

Physical description
A small dark brown and not particularly distinctive spider when on land. Underwater it becomes more distinctive. Its abdomen is covered in small hairs which help it trap a bubble of air. This gives the spider a silvery sheen that resembles mercury as it swims through the water.

Distribution
They inhabit central and northern Europe.

Habitat
Water spiders are found in ponds.

Diet
They live on a diet of insects.

Behaviour
This spider builds a silken retreat under water among plants which it fills with air. The spider swims between the retreat and the surface of the water, collecting air on its furry abdomen and transporting it to its underwater hideaway. When the retreat is complete the spider waits for potential prey to approach. The spider is a good swimmer and will catch prey and subdue it with its venomous jaws. The spider will then return to its retreat to consume its prey.

Like all spiders the water spider needs to shed its skin to grow. Usually the spider will climb out of water onto nearby vegetation and shed its skin there. Occasionally, however, a spider might choose to build a new retreat bubble specially for this purpose.

Reproduction
Mating takes place within the retreat and the female builds a special egg chamber to lay her eggs in. She will stay in this egg chamber to guard her eggs.

Conservation status
They are not listed as endangered on the IUCN Red List.

Notes
The bite from this spider is known to be painful.

Argyroneta means silvery net.