Current status of an amphipod invader,Arcitalitrus dorrieni (Hunt, 1925), in Britain

The synanthropic landhopper Arcitalitrus dorrieni (Hunt) is largely restricted to the south-west of Britain although there are isolated populations outside this area. It has been recorded from 60 new 10-km squares since Harding and Sutton (1988 Harding, P. T and Sutton, S. L. 1988. The spread of the terrestrial amphipod Arcitalitrus dorrieni in Britain and Ireland: watch this niche!. Isopoda, 2: 7–10.  Google Scholar]) last reviewed its distribution. Some of the new records, particularly in south Wales, could be interpreted as meaning that there has been range expansion in this time. However, the evidence is equivocal. It was not possible to explain the distribution of A. dorrieni in terms of association with native plant species. The main means of dispersal still seems to be synanthropic. Arcitalitrus dorrieni has retained a mainly coastal distribution, with penetration inland restricted to peninsular areas (with some notable exceptions, e.g. populations in London).