A new hostplant for Agelastica alni (Linnaeus) (Chrysomelidae) in Britain and observations of the species in Cheshire

摘要

Agelastica alni (Linnaeus) is listed by Shirt (1987) as extinct in Britain with no post1900 records, which was subsequently revised to RDBK (insufficiently known) byHyman (1992), who noted more recent records from the New Forest from 1946,whilst Lewis (2004) and Cox (2007) report a further record from Charmouth, Dorsetin 1958. Following a number of recent records from Cheshire and Lancashire(Stenhouse, 2006), it is likely that a population of A. alni has now re-established innorthwest England. A. alni occurs in wetlands but also in river valleys (Lewis, 2004)and in wet flushes in woodland (Hyman, 1992), usually in open and sunny situations(Cox, 2007). New sites for A. alni in Cheshire discovered during 2007 and 2008 areon woodland margins and in river valleys which is consistent with known ecologicaldata. It is unclear whether the new populations recorded have been accidentallyintroduced on amenity plantings or have naturally spread along river valley corridors,as all populations are present within the River Weaver valley.