Herbivory modifies the lifetime fitness response of Arabidopsis thaliana to elevated CO2

Future increases in atmospheric CO2 may not lead to enhanced plant performance, as has been predicted, when herbivory is considered as, an interactive factor. This study provides experimental evidence that herbivory by the diamondback moth, Plutella xylostella, either decreased or suppressed the lifetime fitness response of Arabidopsis thaliana to elevated CO2 (significant CO2 x herbivory interaction). In addition, even though A. thaliana genotypes had significant differences in their fitness response to increased CO2 the inclusion of herbivory cancelled this genotype-specific response to enriched CO2 conditions. These results have direct implications for evolutionary outcomes in plant populations exposed to elevated CO2 and emphasize the need to evaluate CO2 responses in light of other environmental factors that plants may commonly encounter in natural situations.