The potential effects of climatic change on agricultural insect pests

Abstract

Climate and weather can substantially influence the development and distribution of insects. Anthropogenically induced climatic change arising from increasing levels of atmospheric greenhouse gases would, therefore, be likely to have a significant effect on agricultural insect pests. Current best estimates of changes in climate indicate an increase in global mean annual temperatures of 1°C by 2025 and 3°C by the end of the next century. Such increases in temperature have a number of implications for temperature-dependent insect pests in mid-latitude regions. Changes in climate may result in changes in geographical distribution, increased overwintering, changes in population growth rates, increases in the number of generations, extension of the development season, changes in crop-pest synchrony, changes in interspecific interactions and increased risk of invasion by migrant pests. To illustrate some of these effects, results of a study investigating the impact of climatic change on the European corn borer ( Ostrinia nubilalis) in Europe are shown. Under the climatic changes projected by the Goddard Institute for Space Studies general circulation model, northward shifts in the potential distribution of the European corn borer of up to 1220 km are estimated to occur, with an additional generation found in nearly all regions where it is currently known to occur. A number of priorities for future research into the effects of climatic changes on agricultural insect pests can be identified. These include: examination of the influence of climatic variables on insect pests, long-term monitoring of pest population levels and insect behaviour, consideration of possible climatic changes in research into pest management systems and identification of potential migrants.