Abstract
First, we report the results of the longest‐known field study (9 years) to examine the effects of elevated carbon dioxide (CO 2 ) on leaf miner densities in a scrub‐oak community at Kennedy Space Center, Florida. Here, the densities of all leaf miner species (6) on all host species (3) were lower in every year in elevated CO 2 than they were in ambient CO 2 . Second, meta‐analyses were used to review the effects of elevated CO 2 on both plants ( n =59 studies) and herbivores ( n =75 studies). The log of the response ratio was chosen as the metric to calculate effect sizes. Results showed that elevated CO 2 significantly decreased herbivore abundance (−21.6%), increased relative consumption rates (+16.5%), development time (+3.87%) and total consumption (+9.2%), and significantly decreased relative growth rate (−8.3%), conversion efficiency (−19.9%) and pupal weight (−5.03%). No significant differences were observed among herbivore guilds. Host plants growing under enriched CO 2 environments exhibited significantly larger biomass (+38.4%), increased C/N ratio (+26.57%), and decreased nitrogen concentration (−16.4%), as well as increased concentrations of tannins (+29.9%) and other phenolics. Effects of changes on plant primary and secondary chemistry due to elevated CO 2 and consequences for herbivore growth and development are discussed.