The spider fauna of Britain is probably better known than that of any other country and Wicken Fen is one of the most intensively studied localities which has attracted the arachnologist (people who study spiders). Bristowe (1925) records that collections were made as early as 1869 by W. Farren but the most interesting period of study was during the first quarter of this century when W. Falconer, Dr A.R. Jackson and Dr W.S. Bristowe published a series of important papers. At that time the total recorded Fen species was 161 but this steadily increased to 177 a few years later (Bristowe 1939). The current list is an impressive 251 species (the British fauna totals about 6oo species), of which 4 are listed in the GB Red Data Book and 17 are nationally scarce.

Why are there so many species of spider? For centuries the fen was used for the production of fen crops particularly reed, sedge and 'litter' so that the vegetation pattern today is, to a considerable extent, an artefact. Nevertheless some of the ground surface has probably never been broken and fen conditions have been maintained: two very important factors for the survival of ecologically sensitive species. There are also a range of wetland zones, which grade into drier areas, so providing a range of habitats for spiders and their prey.

Red Data Book spider species with recent records: Neon valentulus, Zora armillata.

Nationally Scarce spider species with recent records: Drassyllus praecifus, Drassyllus lutetianus, Entelecara omissa, Glyphesis servulus, Gongylidiellum murcidum, Hypomma fulvum, Maso gallicus, Saloca diceros, Agraecina striata, Hygrolycosa rubrofasciata, Ero tuberculata, Philodromus albidus, Evarcha arcuata, Marpissa radiate, Tetragnatha striata, Dipoena inornata, Episinus truncates.

Two rare spider species have not been recorded for many decades and are probably extinct:

Hypsosinga heri (Araneidae) - RDB1. Last record 1912
Centromerus semiater (Linyphiidae) - RDB2. Last record 1928