Altitudinal variation in abundance of common wasps (Vespula vulgaris)

Abstract

Common wasps (Vespula vulgaris) were caught in traps set along a 2 km altitudinal transect (455–1590 m a.s.l.) through New Zealand beech (Nothofagus) forest and adjacent alpine tussock in 1990. No German wasps (V. germanica) were caught Very few wasps were caught in the tussock above the bushline (1425 m a.s.l.), compared with the red (N. fusca)/silver beech (N. menziesii) forest from 550 m to 1020 m a.s.l. The highest density of wasps was found in this mid-altitude red/silver beech zone. Wasp density within vegetation zones decreased as altitude increased, but honeydew abundance also varied with altitude. Nevertheless, there is evidence that altitude itself affected wasp abundance. Bird counts before the arrival of common wasps indicated that the mid- altitude zone, where wasps and honeydew were most abundant, was also the main habitat of some native bird species. Therefore, wasps may affect those bird species that are largely confined to this zone.