Water Spider - Argyroneta aquatica

Female length: 8 to 15 mm. Male length: 9 to 12 mm. Although the water spider is velvet-grey out of the water, when it is in the water the air trapped around its body gives it a silvery appearance, which has been likened to quick-silver (mercury). 

The water spider is found in clean, vegetated fresh water with little current e.g. ponds, lakes, dykes and canals where it lives submerged under water throughout most of its life.

The spider is adult throughout the year but most active from spring to late summer.

It creates an underwater silken cell that is filled with air from the surface. Prey is taken back to this retreat for consumption and the cell is also used for mating, egg-laying and over wintering. Occasionally the spider will feed at the surface and moulting normally takes place out of the water.

The species is widespread but scattered in much of the southern half of Britain, very locally distributed further north.

Widespread but local. Probably declining. Established in the Grantham Canal, Ashby Canal, and the Grand Union Canal at Kibworth.

968 British records for this species to 2018