Host-specific Insect Herbivores as Sensors of Climate Change in Arctic and Alpine Environments

Abstract

The distributions of host-specific herbivorous insects along latitudinal and altitudinal gradients, particularly within arctic and alpine environments, provide useful analogs for predicted future changes that are likely to occur over time at any one location, given a gradually changing thermal environment. It is suggested that selected examples of these insect/plant systems can serve as highly responsive sensors of changing climatic temperatures. Distributions of insects that show a restricted occurrence within the overall range of their host plant are predicted to respond more rapidly than the distribution of the host plants themselves. Examples are given to show how these insect-plant systems might be used to monitor long-term temperature change. These examples, drawn from both our published and unpublished work on Homoptera (Insecta), include the following common and widely distributed host plant species within the Northern Hemisphere: Dryas octopetala, Chamerion angustifolium, dwarf Salix species including S. lapponum, and Calluna vulgaris/Erica cinerea.