INSECT PERFORMANCE ON EXPERIMENTALLY STRESSED WOODY-PLANTS - A METAANALYSIS

In this review, we test the hypothesis that abiotic stress increases t he suitability of plants as food for herbivores. We conducted a meta-a nalysis that included 70 experimental studies in which insect performa nce was measured on woody plants subjected to water stress, pollution, and/or shading. Overall, plant stress had no significant effect on in sect growth rate, fecundity, survival, or colonization density. We fou nd great variation, however, in the magnitude and direction of insect responses among studies, most of which was related to insect feeding g uild. In general, boring and sucking insects performed better on stres sed plants, whereas plant stress adversely affected gall-makers and ch ewing insects. Reduction in performance of chewers was greater on stre ssed slow-growing plants than on stressed fast growers. Reproductive p otential of sucking insects was increased by pollution but reduced by water stress. In some cases where sample sizes were small or the treat ment periods short, apparent differences in insect responses to stress were probably artifacts due to inappropriate experimental design.