Stressing food plants by altering water availability affects grasshopper performance

Alexandra Franzke,Klaus Reinhold

doi:10.1890/es11-00095.1

Abstract

Extreme weather events like drought and heavy rain are likely to increase with climate change in Central Europe and may affect nutrient content in plants. They may therefore influence the performance (growth rate, developmental time, mortality, body size/mass, fecundity) and population dynamics of herbivorous insects. We conducted a common-garden experiment on food plants to investigate effects of severe drought and moisture events on reproduction and fitness components in the insect herbivore Chorthippus biguttulus (Orthoptera, Acrididae). Periodic irrigations of food plants were used to simulate a 60% decrease in average summer precipitation (drought treatment), a 40% increase in average summer precipitation (moisture treatment) and a normal summer precipitation (control treatment). Individuals of C. biguttulus that fed on drought-stressed plants showed beneficial effects on life-history traits including an increased reproductive success than grasshoppers that fed on control plants. The opposite was tru...

Highlights

Predictions of future climate change in Central Europe assume that—besides increases in temperature and CO2 concentration—the frequency and intensity of extreme weather events will increase, too (Easterling et al 2000, Meehl et al 2000, Salinger 2005, IPCC 2007)
Because we do not know much about the effects of moisture stress in plants on the performance of herbivores but something more about their performance when feeding on drought-stressed plants, we investigated the differences in grasshopper performance between these two stress levels of food plants
These results suggest that C. biguttulus grasshoppers perform best when feeding on drought-stressed plants and worst when feeding on plants growing under moisture conditions which we propose is an effect of the observed differences in plant compounds

Summary

Introduction

Predictions of future climate change in Central Europe assume that—besides increases in temperature and CO2 concentration—the frequency and intensity of extreme weather events will increase, too (Easterling et al 2000, Meehl et al 2000, Salinger 2005, IPCC 2007). Important environmental influences on plants are severe drought and moisture events which can have strong effects on various plant compounds like the plants’ nutrient content (e.g., protein content, amino acids) and secondary plant defenses (Hsiao 1973, Gershenzon 1984, Bannister 1986, Hoffmann and Parsons 1997). Especially proline, are expected to increase with drought stress in plants (Hsiao 1973). There is evidence that drought stress in plants increases insect survival, growth and reproduction through elevated plant nutrient levels, especially nitrogen and amino acids and lowered plant defenses (Rhoades 1983, White 1984, Mattson and Haack 1987, Hale et al 2003)

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Conclusion