Page 1

RUNNING HEAD

5

NIGMA WALCKENAERI (ROEWER, 1951) (ARACHNIDA: DICTYNIDAE) NEW TO SUFFOLK During September of 2010 a large number of small green spiders were observed hiding under webs stretched across the upper surface of leaves of a large New Zealand Flax (Phormium sp.) in the author’s garden. Curiosity eventually lead to first photographs and then specimens being sent to Paul Lee, the Society’s spider recorder. He was able to confirm the suspicion that they were Nigma walckenaeri, and the first record of this species in Suffolk. It is one of the cribellate spiders that produce extremely fine, woolly strands of silk that are not sticky but entangle the prey trying to walk on it, before the spider strikes. It has been suggested that this spider was introduced into the UK via Kew Gardens and today it is known only from a chain of sites along the Thames valley and also the Severn valley in Gloucestershire. Worldwide, it is restricted to central and southern Europe, parts of North Africa and the Middle East. In the UK it is possible that the species is starting to spread, with numerous records from south Essex and an isolated cluster from around Colchester in north Essex. It is perhaps of note that the Phormium specimen was brought to Suffolk when the author moved from Great Horkesley, near Colchester, and not far from one of the Colchester localities for this spider. As such, it cannot be ruled out that this colonisation of Suffolk has been assisted by human activity. The spider is said to favour large, slightly folded leaves and additional spiders were soon identified on a Holly adjacent to the Phormium and then also on another plant elsewhere in the back garden, so even if it was introduced, it has started to spread. The photograph (Plate 6) was of an individual that favoured a groove in the nearby garage door. The leaves of Ivy, Forsythia and Lilac are also said to be favoured by the spider, all of which occur in the garden so there are ample opportunities for this attractive species to establish itself. It is an autumnal and winter species, with records for Essex coming mainly from August through to January (www.essexfieldclub.org.uk/ portal/p/Species+Account/s/Nigma%20walckenaeri). Adrian Knowles Jessups Cottage, London Road, Capel St Mary, IP9 2JJ

Trans. Suffolk Nat. Soc. 46 (2010)


A. Knowles Plate 6: A cribellate spider, Nigma walckenaeri (Roewer), new to Suffolk in 2010 (p. 5).

NIGMA WALCKENAERI (ROEWER, 1951) (ARACHNIDA: DICTYNIDAE) NEW TO SUFFOLK  

Adrian Knowles

Read more
Read more
Similar to
Popular now
Just for you