Arachnological History: Whatever Happened to the Victorian Introduction of Eratigena atrica s.s. (Agelenidae) to Southport, Lancashire?

摘要

The nomenclature of what is now the Eratigena atrica group of large house spiders (E. atrica s.s.*, E. saeva and E. duellica) is complicated. To aid the understanding of this article, a brief history of name changes is provided in Table 1.It is now established that, prior to the mid-1900s, members of the E. atrica group were rarely found north of an east-west line drawn along the North Wales coast (Bristowe, 1939; Oxford, 2009, 2011). Before this time records from further north were usually from known imports, often of E. atrica s.s., which is generally rare in Britain but common in continental Europe and the Irish Republic. For example, a male of E. atrica s.s. was discovered in Forfar post office in 1927 in a Royal Mail bag from Ireland, and the same species was reported from stacks of locomotive coal in a railway siding at Carlisle in 1933 (Parker, 1984). Merrett (1980) also illustrated the epigyne of a female in the Carlisle Museum collection taken in 1971. Some of these importations were probably of single individuals and so once caught the invasion was over. The 1933 discovery in Carlisle clearly involved several individuals, since 'specimens', in the plural, were examined (Parker, 1984). Whether the 1971 Carlisle female was partof a continuing population, or a separate importation, is not known. In the case of introductions to Co. Durham pre-1896 and Newcastle upon Tyne in 1887 (Hull, 1896) the identity of the species recorded isuncertain because of a very fluid nomenclature at the time. Hull (1896) identified the mature Newcastle male as Tegenaria atrica; unfortunately the specimen has since been lost (Oxford & Smith, 2014). Eratigena atrica s.s. was definitely taken from Newcastle in 1949 (Parker, 1959). More recently, David Smith discovered a thriving population of E. atrica s.s. in the Newcastle area (Burnopfield, Co. Durham), which was subsequently found to be common over some 700 km2 centred on Newcastle (Smith & Oxford,2009; Oxford & Smith, 2014). It seems likely that this population stemmed from one or more introductions in Victorian times, or even earlier.