Implications of Climate Change for Cereal Aphids on the Great Plains of North America

The Great Plains of North America represent a vast expanse of fertile land characterized by extreme weather conditions, generally limited rainfall, and long distance migration of insect pests, including aphid species that are especially damaging to graminaceous crops. An increase in annual mean temperatures would have certain predictable consequences for cereal aphid populations via direct effects on aphid biology, and indirectly through effects on plants and natural enemies. However, any sustained shift in prevailing wind patterns associated with atmospheric warming could generate an unpredictable cascade of ecological consequences for both agriculture and cereal aphids, mediated largely by changes in rainfall patterns and migration pathways, respectively. The direct effects of warming would be generally beneficial for aphids through most of the year, except in summer when high temperatures are already limiting to survival in much of the region. Additional indirect effects will be mediated by changes in the phenology of cereal crops and wild host plants, adjustment of agronomic practices, and likely impacts on natural enemies. Possible adverse consequences for agriculture include northern range expansions of pest aphid species, prolonged periods of asexual reproduction in autumn, improved survival of overwintering eggs, earlier development of spring populations, and more efficient virus transmission over greater distances.