ABSTRACT Broad scale ecological theory predicts that latitudinal variation in primary productivity will influence interactions between plants and their insect herbivores. Specifically, it has been hypothesized that herbivore-plant interactions are more intense and plant defenses are more developed at lower latitudes than at higher latitudes where productivity is lower. However, the ultimate outcome of insect-plant interactions may not be so easily predictable because it could be determined not only by plant traits at a particular location, but also by productivity driven trophic dynamics, insect population size, individual insect feeding rates, and other latitude specific ecological factors. In this paper, I review the prior work on how insects, plants, insect-plant interactions, and tri-trophic interactions with specific regard to insect herbivory vary with latitude. Because these latitudinal gradients encompass the range of temperatures expected with climate change, I use this prior work to predict how that change could influence complex ecological interactions between insects, host plants and insect predators. This led to the predictions that with warming, rates of herbivory will increase, there will be a lag in any concomitant increase in plant defense with these increases in herbivory, there should be a shift towards greater top-down control of herbivory, and specialist herbivores may be at greater risk. Insight on limitations of the predictive power of latitudinal studies and suggestions for future research in this area are offered.
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