Data for: More than what they eat: Uncoupled biophysical constraints underlie geographic patterns of herbivory

Data used in Lynn et al. 2022 at Ecography. The first dataset contains
data from published studies used for the main analyses of the paper. The
second dataset is from Lynn and Fridley 2019 in Journal of Plant Ecology
used for figure 3. The abstract from the paper is: Herbivory rates have
classically been hypothesized to decrease from the tropics towards higher
latitudes because the more benign abiotic conditions in tropical systems
foster greater ecosystem complexity including greater intensity of biotic
interactions. However, attempts to quantify latitudinal patterns of
herbivory often fail to support this hypothesis. While biases have been
offered as explanations for null results, here, we argue that framing the
question of latitudinal variation in herbivory around nutrient and
energetic constraints of insect herbivores and plants may provide
mechanistic explanations of latitudinal herbivory patterns. As a case
study, we focused on sodium as an uncoupled nutrient between herbivore and
plant communities: sodium is a key limiting micronutrient for herbivore
neural and muscular development while present at orders of magnitude lower
concentrations in plants. We compared sodium deposition with latitude,
mean annual temperature (MAT), and actual evapotranspiration (measure of
primary productivity; AET) in their ability to predict consumed percentage
leaf area from published datasets. Leaf percent herbivory increased with
sodium deposition and MAT and decreased with latitude but was unrelated to
AET. Sodium had comparable effect size and predictive ability to either
MAT or latitude. Additionally, herbivory was highest in locales with both
high sodium deposition and high MAT. Our hypothesis that geographic
variation in herbivory is driven by an interaction of unrestrictive
temperature environments (high MAT) and limiting nutrient supply to
herbivores (high sodium deposition) was strongly supported. We propose
that greater generality, predictability, and theoretical development on
geographic variation in herbivory will arise from a refocus on the
biophysical constraints (e.g., productivity, micronutrient availability,
leaf mass consumed) that ultimately control consumer interactions rather
than latitude per se. This refocus is likely to open new
hypotheses for the evolution of defense syndromes across plant populations
and communities based on the specific geography of limiting nutrients.