Cascading ecological effects caused by the establishment of the emerald ash borer Agrilus planipennis (Coleoptera: Buprestidae) in European Russia

Emerald ash borer, Agrilus planipennis, is a destructive invasive forest pest in North America and European Russia. This pest species is rapidly spreading in European Russia and is likely to arrive in other countries soon. The aim is to analyze the ecological consequences of the establishment of this pest in European Russia and investigate (1) what other xylophagous beetles develop on trees affected by A. planipennis, (2) how common is the parasitoid of the emerald ash borer Spathius polonicus (Hymenoptera: Braconidae: Doryctinae) and what is the level of parasitism by this species, and (3) how susceptible is the native European ash species Fraxinus excelsior to A. planipennis. A survey of approximately 1000 Fraxinus pennsylvanica trees damaged by A. planipennis in 13 localities has shown that Hylesinus varius (Coleoptera: Curculionidae: Scolytinae), Tetrops starkii (Coleoptera: Cerambycidae) and Agrilus convexicollis (Coleoptera: Buprestidae) were common on these trees. Spathius polonicus is frequently recorded. About 50 percent of late instar larvae of A. planipennis sampled were parasitized by S. polonicus. Maps of the distributions of T. starkii, A. convexicollis and S. polonicus before and after the establishment of A. planipennis in European Russia were compiled. It is hypothesized that these species, which are native to the West Palaearctic, spread into central European Russia after A. planipennis became established there. Current observations confirm those of previous authors that native European ash Fraxinus excelsior is susceptible to A. planipennis, increasing the threat posed by this pest. The establishment of A. planipennis has resulted in a cascade of ecological effects, such as outbreaks of other xylophagous beetles in A. planipennis-infested trees. It is likely that the propagation of S. polonicus will reduce the incidence of outbreaks of A. planipennis.