This article was first published in the Newsletter of the London Natural History Society, No. 240 February 2016
An excursion to this small nature reserve in west London was arranged jointly with London Wildlife Trust at fairly short notice, and was advertised not in the calendar but on the Society’s website and on the www.wildlondon.org website.
The day was a pleasant, mild, windless morning; over twenty adults, two teenagers and eight small children assembled at the LWT hut, several claiming they were ‘arachno-beginners’.
Some blue webs of Amaurobius sp. and the ‘spokes of a wheel’ web of Segestria senoculata were immediately pointed out on the hut itself. The group walked down the path into the reserve and soon found some large well-marked Garden Spiders (Araneus diadematus) on their orb webs, as well as some smaller Metellina segmentata web-spinners; both sexes of the latter were found sharing a web, as is often the case. There was some discussion of the difference between the sexes in spiders, and some members of the group were horrified to have it confirmed that after sex some female spiders kill and eat their mates, but were quietly amused to learn that in other species the low nutritive value of the males mean that she doesn’t bother.
One of the Metellina females was removed from its web and placed on a flat surface to demonstrate the weak back legs of these spiders which drag as they walk – characteristic of two families (Araneidae and Tetragnathidae) the females of which use their back legs for manipulating silk rather than to support their (heavy) abdomens.
Sweepnetting ivy-covered trunks of some of the birch trees produced specimens of the ‘buzzing spider’ Anyphaena accentuata (Anyphaenidae) with its characteristic ‘pair of inverted commas’ markings on the abdomen. Other characteristics were noted: they bear numerous particularly aggressive spines, and they are pale-coloured spiders with dark markings – unlike the blue-web spiders Amaurobius spp. which we found under dead logs, which are dark-coloured spiders with paler markings.
Among the ivy growing on the ground of the wood numerous sheet webs were seen, with the spiders hanging underneath the webs. These were the common money spider Linyphia triangularis.
Much of the reserve is secondary woodland dominated by birch and goat willow, many trees festooned with ivy, but there are a few open glades. In the largest of these we searched the grass for ground-living spiders and found several wolf spiders: Pardosa nigriceps with annulated legs, and at the edge of ‘the meadow’ a single specimen of the handsome Pardosa saltans a woodland wolf spider.
The meadow boasts several spectacular anthills but it was thought best not to disturb this fragile area of acid grassland – at a future date some pitfall-trapping might produce some interesting acid-grassland spiders.
Several mouse spiders (Clubionidae) were found outside the meadow itself but they proved to be juveniles; apart from adults of C. terrestris one of the commonest woodland species, none of the others could be identified with certainty. A single specimen of the small green spider Nigma walckenaeri was collected by sweepnetting, but its characteristic ‘sewn-leaf-webs’ were not seen.
The waterside vegetation around two small ponds produced juvenile specimens of Tetragnatha montana with their characteristic long legs and elongated abdomens. Under some birch logs at the far end of the reserve a large Tegenaria probably T. gigantea was seen on a big cobweb but it escaped into the brambles. Two large money spiders were captured which proved to be Megalepthyphantes sp. a handsome species which seems to be increasing in both range and numbers in the London area. It still awaits description as a recognised species. (see photos).
On the way back to the hut one last sweep of a voluminous ivy patch produced the find of the day: two specimens of the beautiful green crab-spider Diaea dorsata! (see photos) This is the first contemporary record of this spider from central London (that is, within the Circular Road) if not the actual old county of London, and it is interesting to find it in secondary woodland. It has been found in recent years at Hounslow Heath and Cranford Park near Heathrow, in woodland of indeterminate age, but not any further into London. The only previous records are from the 19th century; at Kenwood House and Hampstead Heath. There’s been no sign of it on Hampstead Heath ever since.