Status and public perception of the ‘New Zealand flatworm’, Artioposthia triangulata (Dendy), in Northern Ireland

Since the terrestrial flatworm, Artioposthia triangulata (Dendy), was first recorded in Northern Ireland in 1963, sightings from the general public have been collected by the Department of Agriculture for Northern Ireland. By the end of 1997, the cumulative total had reached 1019. Prior to 1989, the number of reports averaged 3.5 per year but this increased substantially in 1990 following intense media interest in the flatworm. Sightings peaked at over 300 in 1995. A. triangulata was found in every major town in the province and the number of reports correlated positively with human population density. Adult A. triangulata were found throughout the year but especially in spring and early summer with most sightings from gardens (79.5%), grassland (6.6%) and vegetable plots (6.0%). Of the reports which refer to the impact of A. triangulata on earthworm populations, 22.2% stated that earthworms were absent, 42.4% stated low and 35.4% felt that the earthworm population was unaffected. The validity of using information from the public to assess the spread and impact of A. triangulata is discussed.