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Variation in plant defense suppresses herbivore performance

June 19, 2018

Defensive variability of crops and natural systems can alter herbivore communities and reduce herbivory. However, it is still unknown how defense variability translates into herbivore suppression. Nonlinear averaging and constraints in physiological tracking (also more generally called time-dependent effects) are the two mechanisms by which defense variability might impact herbivores. We conducted a set of experiments manipulating the mean and variability of a plant defense, showing that defense variability does suppress herbivore performance and that it does so through physiological tracking effects that cannot be explained by nonlinear averaging. While nonlinear averaging predicted higher or the same herbivore performance on a variable defense than on an invariable defense, we show that variability actually decreased herbivore performance and population growth rate. Defense variability reduces herbivore performance in a way that is more than the average of its parts. This is consistent with constraints in physiological matching of detoxification systems for herbivores experiencing variable toxin levels in their diet and represents a more generalizable way of understanding the impacts of variability on herbivory. Increasing defense variability in croplands at a scale encountered by individual herbivores can suppress herbivory, even if that is not anticipated by nonlinear averaging.

Publication Year 2018
Title Variation in plant defense suppresses herbivore performance
DOI 10.1016/j.cub.2018.04.070
Authors Ian S. Pearse, Ryan Paul, Paul J. Ode
Publication Type Article
Publication Subtype Journal Article
Series Title Current Biology
Index ID 70197743
Record Source USGS Publications Warehouse
USGS Organization Fort Collins Science Center