Interactions among herbivores in three polluted pine stands

Abstract

Succession of insect attacks on young Scots pines (Pinus sylvestris L.) was studied in heavily, moderately and slightly polluted pine stands within a 3-km distance from a prominent emission source in western Finland. The total number of pest species was highest in the moderately polluted stand but, unlike other herbivores, aphids were also abundant in the heavily polluted stand. A few positive but no negative interactions were detected between herbivores, which suggests that insect species may benefit from a previous occurrence of other species in the same tree.