Harvestmen abundance and diversity within lodgepole and Scots pine plantations of Scotland and their impact on pine beauty moth populations

Abstract

Natural enemies are important contributors to the differences in Panolis flammea abundance observed in Scots pine and lodgepole pine plantations in Scotland. This study compared the diversity and abundance of harvestmen species in Scots pine sites and lodgepole pine sites within forests of Northern Scotland. While the native Scots pine sites have never been affected by high numbers of P. flammea, the chosen lodgepole pine sites have had extensive P. flammea outbreaks in the past. Three harvestmen species, Mitopus morio, Oligolophus palpinalis and Oligolophus tridens had markedly different abundances between the forest habitats over the sampling period. Peaks in harvestmen abundance within the Scots pine habitat occurred at a time when P. flammea larvae were most vulnerable to attack (as early instar larvae). In contrast, the abundance of harvestmen within the lodgepole pine habitat was low at this vulnerable time but peaked later in the summer at a time when P. flammea were least affected by predation.