I was at Ashleworth early on the morning of 20 October and noticed that, on a coldish morning with a hint of frost, there was a huge quantity of spiders’ webs, all looking white and liquid, and showing up well in the cold air; at the top of the vertical stems of docks and bullpate (Deschampsia), and also in horizontal carpets on the grass. I don’t remember seeing quite so many before, but it may be that I just didn’t notice beforehand. It was a very attractive sight: pity I didn’t have a camera with me!
The hay had not been cut this year on some of the reserve hayfields, nor on the fields in the SSSI beyond. I wondered if the fact that the hay hadn’t been cut might have allowed more spiders to survive.
I asked the Gloucestershire Naturalists’ Society’s Spider Recorder, David Haigh for his comments, and his answer is reproduced below.
Certainly Mike, undisturbed grassland provides a greater opportunity to exploit the increased vertical structure to attach webs. I am sure your conclusion was correct, re absence of a hay cut. The taller plant stems are used as scaffolding to support webs of a greater variety of spider species compared with a mown sward. These silvery sheets of silken web are generally called gossamer and most often seen on autumn mornings when dew condenses on the threads.
The majority of spiders’ webs you have been observing come from the family Linyphiidae (Money Spiders). ‘The World of Spiders’ by W.S. Bristowe (Collins New Naturalist, 1958) quotes the following species responsible for gossamer on an undisturbed field in Surrey: Dicymbium nigrum, Oedothorax fuscus, Savignia frontata, Erigone dentipalpis, Erigone atra, Bathyphantes gracilis and Lepthyphantes tenuis. Such are the numbers of these spiders that Bristowe calculated densities of over a million Linyphiidae per acre from August to December in Surrey.
Previous pit-fall trapping programmes at Ashleworth, 2008, recorded all the above and additional Linyphiids. Webs at the top of docks and Deschampsia will probably belong to the family Dictynidae (Lace-Web spiders), genus Dictyna. These spiders produce a veil of silk at the tops of old flower stems, the web only being easily visible on dew laden mornings. These spiders would not normally be recorded from pit-fall traps.
Gossamer has exercised poets, e.g.
Chaucer: ‘Sore wondren some on cause of thonder, on ebb and flow, on gossamer, and on mist.’
Thomson spoke of gossamer as ‘filmy threads of dew evaporate’
Qharles: ‘and now autumnal dews are seen to cobweb every green’.