Argyroneta Surfaces Again

By John Partridge

Argyroneta aquatica The Water Spider, Argyroneta aquatica, has a fascinating lifestyle, living its life underwater in an air bubble which is held in a web tent, where the spider builds its nest, eats, mates and lays eggs, emerging from the bubble to catch its food underwater, and coming to the surface from time to time to collect another supply of air, although this may happen only infrequently, as carbon dioxide in the bubble can be disposed of, and oxygen replenished, by diffusion into the surrounding water.

Photo: BAS Slide Set

It is found throughout Britain, although apparently with a southern bias, in clean slow moving water. We have a few Worcestershire records, but I have been looking for it, unsuccessfully, for the last two years, and quizzing Don Goddard and Will Watson as to whether they had found it while doing their aquatic bug-hunting, all without success, until early September, when Harry Green gave me a few spiders to identify, including two that had come up with weeds from Lower Bittell Reservoir, where he had been bug-hunting with Will Watson and John Day (*see NOTE). Although both specimens were pre-adult, the habitat, and the hairy abdomen and third and fourth legs confirmed them as A. aquatica.

Bristowe, in The World of Spiders - Collins New Naturalist series- says that as a boy he used to watch them swimming below the water surface, with the air trapped in the body hairs giving them the appearance of quicksilver. Most people seem to find them, if at all, by bringing weed to the bank and waiting for the spider to run out. Roberts says that juveniles can be distinguished by tossing them onto the water; most spiders will run rapidly to dry ground, but the water spider young dive down below the surface.

Are there any fishermen out there who have dragged up water weeds on their hooks, and found a water spider running out? Are there any of you with pools who have ever seen the silver movement below the surface? If so, I should very much like to hear from you.

Records to date for Worcestershire VC37.

Trotshill Lane SO85 tetrad X Meiklejohn, J.W.
Defford SO94 tetrad G Meiklejohn, J.W.
Grimley SO86 tetrad F Meiklejohn, J.W
Lower Bittell N. Reservoir SP07 tetrad C Green, G.H. Det. Partridge, J
Hartlebury Common SO87 tetrad F Taylor, M.N
Bourne Brook SP08 tetrad G Birmingham River Survey
Bourne Brook SP08 tetrad L Birmingham River Survey
Foxcote Pond SO98 tetrad G Stenson, C

NOTE: Lower Bittell Reservoirs are not open to the public - we were given special permission to visit, for which many thanks.

References

ROBERTS, Michael J 1985. Spiders of Great Britain and Ireland. Harley Books.
BRISTOWE, W. 1958 The World of Spiders. Collins New Naturalist Series.
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