|The Wasp Spider, Argiope bruennichi (Scopoli) in SW Britain.
Until recently the wasp spider was a great rarity which was only encountered in Dorset & Hampshire or on visits to the continent and was greeted with considerable excitement by arachnologists. The bold black and yellow stripes on the abdomen of the female make this spider one of the most distinctive spiders in Britain and combined with the white silken zigzag in its web make it is difficult to misidentify.
It was first reported in Britain from the SE coast in the 1940’s and quickly became resident on the coast of Dorset and Hampshire (Merrett 1992). This remained the centre of the British populations over the following forty years with occasional records from Kent and Cornwall.
In the early 1990’s records began to appear in the SW, these were initially isolated individuals but then between 1995 and 1998 a number of large populations were discovered in Plymouth ( Andy Stevens pers com), Exmouth (Alexy Burton pers com) and Hawkchurch, N Devon (Toddy Cooper pers comm). Once established these have seeded other populations in nearby patches of suitable habitat and as a result the wasp spider is now very common in some parts of Devon, see map (Smithers 2000).
istribution of Argiope bruennichi in the SW
Pre 1990 records Post 1990 records
The habitat required for the successful establishment of this species is tall rank grassland such as abandoned meadows field margins and roadside verges that have been unmanaged for a least a year or two. These provide a mixture of grass tussocks and the dead and living stems of tall herbs such as dock, which provide suitable structures for web attachment.
Work on A bruennichi in Bavaria where this species also colonises temporary grasslands has suggested that spiderlings of A bruennichi are obligatory aeronaughts upon emerging from their cocoon. Spiders from such ephemeral habitats often display a greater tendency to disperse than those occupying more stable habitats, thus increasing their chances of reaching suitable new areas before the old site is lost (Follner & Klarenberg, 1995).
Observations at one of the Plymouth sites, has provided enough data to provide a preliminary outline of the life history of this species. Egg cocoons are produced in the autumn amongst the low vegetation or in the base of grass tussocks. The cocoons comprise a papery outer layer which is waterproof and an inner layer of silken coils that act as insulation and also protects the inner egg compartment form parasites that find it difficult to oviposit through this flexible layer . The spiderlings hatch from the eggs in late autumn but remain inside until the following spring. The spiderlings disperse by ballooning at this point, some travelling many kilometres while many travel only a few meters from their cocoons. The early instar spiderlings live in the base of the vegetation until the early summer when they move into the centre of grass tussocks or other clumps of vegetation where they spin small orb webs, which intercept small flying insects. As the spiders grow they produce larger webs and increase the height of the web above the ground, these then tend to intercept grasshoppers and assorted flies.
Having established several large population centers the wasp spider is destined to become a common element of the invertebrate fauna in SW Britain unless we experience a series of severe winters which could dramatically effect the mortality of spiderlings in their cocoons.
Merrett, P. (1992) Argiope bruennichi in Britain. Spider Recording Scheme Newsletter.
Follner, K. & Klarenberg, A. (1995) Aeronoughtic behaviour of the wasp like spider Argiope bruennichi (Scopoli) (Araneae, Argiopidae). Ruzicka, V. (ed) Proceedings of the 15th European Colloquium of Arachnology. Czech Academy of Sciences. Ceske Budejovice.
Smithers, P (2000) Argiope bruennichi (Scopoli, 1772): A Review of Recent Records. Newsletter of the British Aracnological Society. 87. 2-3.
Peter Smithers, Dept Biological Sciences, University of Plymouth, Drake Circus Plymouth, Devon.