Lixus iridis Olivier (Curculionidae) in Surrey, now established in Britain

摘要

Lixus iridis Olivier (Fig. 1) is a conspicuous and widespread member of the genus Lixus Fabricius (Curculionidae: Lixinae (formerly called Cleoninae)). Lixus is the largest genus of the subfamily and includes over 500 species worldwide (Csiki, 1934), 75 of which occur in Europe (Alonso-Zarazaga et al., 2017). Like all of this generally thermophilic subfamily, Lixus is poorly represented in Britain: Morris (2002) lists six species on the British list, but adds that 'two are of ancient or dubious provenance [iridis and filiformis (Fabricius)] and three are almost certainly ... extinct [paraplecticus (Linnaeus), angustatus (Fabricius) = pulverulentus (Scopoli) and vilis (Rossi)]', leaving only one, the recent colonist Lixus scabricollis Boheman, ‘definitely extant' at his time of writing. The status of members of the genus in Britain was examined in detail by Mann, Hancock & Morris (2005), who reached the same conclusion as Morris, except that they treated Lixus iridis as an ‘extinct native'. L. iridis is one of five species of Lixus included by Fowler (1891): Fowler doubted its British credentials but could see ‘no reason why it should not be a British species'. He cited two localities dating to 1836 or before: 'Hornsea Fen’ (Cambridgeshire) and 'Mildenhall' (Suffolk) (collected by J.A. Power). Mann, Hancock & Morris (2005) recognised that ‘Hornsea Fen' was a misinterpretation of J.A. Power's notes, and concluded that the two credible historic British localities were Mildenhall and the Isle of Ely in Cambridgeshire (although the current authors feel that the latter, which is not supported by any specimen, is probably the result of a misinterpretation). Most likely, L. iridis is one of those species that arrives in Britain from time to time, in one way or another (usually introduced), sometimes establishing temporary breeding populations, and then disappears. In this respect its ‘return’ to Britain is very like that of the weevils Peritelus sphaeroides Germar (M