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Water spider

Mark Webster

Water spider

Scientific name: Argyroneta aquatica
There are several species of spider that live in our wetlands, but the water spider is the only one that spends its life under the water. In its pond habitats, it looks silvery because of the air bubbles it traps in its hairs.

Species information

Statistics

Body length: 0.8-1.5cm

Conservation status

Common.

When to see

January to December

About

The water spider lives underwater, building a bell-shaped web between underwater plant stems. It can be spotted as it comes to the water's surface to trap air in the hairs on its body, which it takes down to fill the web, or 'diving bell' (hence its other common name of 'diving bell spider'). It lives in this large air bubble during the day, and hunts at night. Mating takes place within the web retreat and the female builds a special egg chamber in which she lays and guards her eggs. Water spiders can be found in weedy lakes and ponds, and very slow-flowing streams.

How to identify

The water spider is the only spider that spends its life underwater. If caught while pond dipping, it can be recognised by the silvery air bubble it carries on the hairs on its body. Out of the water, it looks grey-brown. Males are larger than females.

Distribution

Widespread.

Habitats

Did you know?

The Water spider is the only spider in the world that lives underwater.