Strolling along, minding my own business... I spotted something familiar among the Fleabane and grasses beside the Radipole hide trail last week. It was (and still is) a Wasp Spider (Argiope bruennichi), an unmistakeable species with an abdomen banded with vivid black and yellow stripes, which inspired its common name. There have been anecdotal sightings of the species at Radipole in the past but this is the first one I have seen here, so it was a very welcome encounter. You could be forgiven for thinking that this rather exotic-looking beast is out of place in Britain, but this species is widespread in western Europe, including as far north as Sweden. It seems to be a relatively recent inhabitant this side of the Channel, having been recorded first in 1922 in East Sussex. It’s impossible to say for sure how they got here but they seem to find the place to their liking and have spread inland from the south coast and Thames estuary into southern counties, and are certainly well established in Dorset.
Like the more familiar garden spiders, they spin vertical orb webs, suspended fairly low in unmanaged, undisturbed grass and vegetation where they can catch grasshoppers and any other insects which come by. A distinguishing feature that is sometimes built into the web is a thicker zigzag pattern in a narrow segment, called the stabilimentum, It seems that its function is uncertain – it has been suggested that it may attract prey, or be a visual deterrent to creatures that could blunder into the web and damage it. This particular one was more than living up to its name when spotted, as she was tucking into a wasp.
The other thing that made this one stand out was her sheer size – she had obviously been feeding well and looked fit to burst. I checked on her regularly, not wanting to miss such a phenomenon, but after a few days discovered that she had deflated considerably overnight and looked a shadow of her former self.
Pressure's on...
...and relax.
The reason for this drastic weight loss was the presence of her egg cocoon, concealed close to the nest. It’s a papery-looking, urn shaped construction with a rim at the top, made from a complex arrangement of different types of silk, which is suspended in the vegetation. The eggs inside will hatch in the spring, and the spiderlings will remain within for a while before dispersing. Meanwhile their mother will live only into the autumn, by which point her one year life-cycle will be complete. She gets to live rather longer than her mate though; the male of the species is comparatively small and inconspicuous, and sooner or later ends up as a female’s dinner after mating.
Having unburdened herself of her eggs and a lot of silk, Sophie, as we have named her, has returned to her web and seems to be feeding and gaining condition. Could she be building up to another reproductive effort while there's still time? If she adds anything to her urn collection we’ll let you know.
If you want to pay her a visit, walk to the bench on the hide trail, than come back south about 26 paces and carefully look down into the herbage to the left of the path, where you may find her sitting in the centre of the web. There’s another one – showing well, as they say – further south on the same path, much nearer the bridge. No eggs there yet but, but that could change, assuming that she’s had that crucial romantic meal for one.
Well certainly did see Sophie this morning + egg sac - what a brilliant couple of hours - Beardies, Kingfisher, Bittern fly by, Sparrowhawk :-) Really enjoyable.