Over the last few years our ecologists and countryside management team have noticed an increase in this striking spider while on site visits.
The wasp spider (Argiope bruennichi) is a relative of our common garden spider (Araneus diadematus). It is thought to have been introduced, and was first recorded in Britain in 1922. The female can be very large (especially in late summer, prior to laying eggs) and the thorax is brightly coloured with yellow, black and white stripes, resembling a wasp. In contrast, the male is tiny, and doesn’t resemble the female at all. The female spins an orb web in tall grassland. The web is very characteristic, with an obvious zig-zag pattern (called a “stabilimentum.”), and the presence of the spider can be confirmed by the web alone. They generally feed on grasshoppers, as well as other insects that get caught in the web.
Like species such as the long-winged conehead (Conocephalus discolor), Roesel’s bush cricket (Metrioptera roeseli) and little egret (Egretta garzetta), the wasp spider has increased dramatically in range over the last few decades, possibly due to climate change. Initially confined to the coast in the south-east of England, recently this spider has colonised most of the southern counties, including Dorset, Devon, Wiltshire, Kent and Cornwall. Given that this species is unmistakable and of a very large size, it is unlikely that it would be overlooked for long in a new area.
Numbers of this species noted on sites by Ecosulis range from 2-3 to several hundred in one relatively small overgrown field encountered on an invertebrate survey in South Devon last year.
Although this spider has been known to occasionally bite humans, the bite is not dangerous, and generally the spiders are not interested in biting humans.
Although not protected in the UK, the wasp spider is of nationally scarce status in the UK. Little management is necessary to encourage or conserve these spiders, which seem to thrive in tall, unmown grassland and other low vegetation.
Spider Recording Scheme: http://srs.britishspiders.org.uk/portal.php/p/Summary/s/Argiope+bruennichi
British Arachnological Society: http://wiki.britishspiders.org.uk/index.php5?title=Argiope_bruennichi