Climate Change Research Today is a free monthly online journal that collates and summarizes the latest research about Climate Change, including details on causes, effects, impact, facts, myths, information.

Climatic unpredictability and parasitism of caterpillars: implications of global warming.

Stireman JO, Dyer LA, Janzen DH, Singer MS, Lill JT, Marquis RJ, Ricklefs RE, Gentry GL, Hallwachs W, Coley PD, Barone JA, Greeney HF, Connahs H, Barbosa P, Morais HC, Diniz IR

Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, LA 70118, USA.

Insect outbreaks are expected to increase in frequency and intensity with projected changes in global climate through direct effects of climate change on insect populations and through disruption of community interactions. Although there is much concern about mean changes in global climate, the impact of climatic variability itself on species interactions has been little explored. Here, we compare caterpillar-parasitoid interactions across a broad gradient of climatic variability and find that the combined data in 15 geographically dispersed databases show a decrease in levels of parasitism as climatic variability increases. The dominant contribution to this pattern by relatively specialized parasitoid wasps suggests that climatic variability impairs the ability of parasitoids to track host populations. Given the important role of parasitoids in regulating insect herbivore populations in natural and managed systems, we predict an increase in the frequency and intensity of herbivore outbreaks through a disruption of enemy-herbivore dynamics as climates become more variable.

Published 30 November 2005 in Proc Natl Acad Sci U S A, 102(48): 17384-7.
Full-text of this article is available online (may require subscription).

© 2004-2008 Climate Change Research Today. All Rights Reserved.