DOI: 10.5061/dryad.qjq2bvqnz
title: Neutrality in plant–herbivore interactions

description: Understanding the distribution of herbivore damage among leaves and
 individual plants is a central goal of plant-herbivore biology. Commonly
 observed unequal patterns of herbivore damage have conventionally been
 attributed to the heterogeneity in plant quality or herbivore behavior or
 distribution. Meanwhile, the potential role of stochastic processes in
 structuring plant-herbivore interactions has been overlooked. Here, we
 show that based on simple first principle expectations from metabolic
 theory, random sampling of different sizes of herbivores from a regional
 pool is sufficient to explain patterns of variation in herbivore damage.
 This is despite making the neutral assumption that herbivory is caused by
 randomly feeding herbivores on identical and passive plants. We then
 compared its predictions against 765 datasets of herbivory on 496 species
 across 116° of latitude from the Herbivory Variability Network. Using only
 one free parameter, the estimated attack rate, our neutral model
 approximates the observed frequency distribution of herbivore damage among
 plants and especially among leaves very well. Our results suggest that
 neutral stochastic processes play a large and underappreciated role in
 natural variation in herbivory and may explain the low predictability of
 herbivory patterns. We argue that such prominence warrants its
 consideration as a powerful force in plant-herbivore interactions.
description: The details can be found on the HerbVar website: https://herbvar.org/protocols.html and the supplement of Pan & Wetzel 2024. 
description: # Neutrality in Plant–Herbivore Interactions
 ## Description of the data
 and file structure `HV_data_cleaned_long.csv` and
 `HV_data_cleaned_short.csv` * surveyID: surveyID * MAT: Mean annual
 temperature in C * MAP: Mean annual precipitation in mm * plantHeight_cm:
 plant height in cm * numLeaves: number of leaves on a single plant *
 plantID3.long: Unique plant ID * Lat: plant latitude in degrees decimals *
 Long: plant longitude in degrees decimals (some of the coordinates
 censored for protection of rare plants) * percHerbPlant_EstimationMethod:
 did the survey follow HerbVar protocol? 'hvp' is the highest
 precision, followed by 'hv', and then the bin resolution * PI:
 Principal investiger * siteSimp: Site name * leafID: Leaf ID * percLf:
 Proportion herbivory on the leaf * species: plant species * genus: plant
 genus * sp: plant species name * family: plant family * n.avg: median
 number of leaves within a survey ## Sharing/Access information Data was
 from the HerbVar Network (). While using the
 data is fair game, it is still recommended that one please consult the
 steering committee before using the data in a publication. ##
 Code/Software The code used for the simulations and analyses is available
 on Zenodo. The custom R package *herbivar* and a vignette on how to fit
 the neutral model to herbivory data are available on Zenodo as an archived
 version and as a maintained version via GitHub
 ( `herbivar_0.2.0.tar.gz` This
 is the R package. Install with `install.packages(PACKAGE_PATH, repos =
 NULL, type = "source")`
 `Using_‘herbivar’_to_Fit_Neutral_Models.html` This is the knitted vignette
 on how to fit the neutral model to herbivory data
 `manuscript_analysis.zip` This zip file contains numberd scripts that
 should be run sequentially. The R scripts derive the model objects and
 perform calculations. The `6_main_manuscript_results.html` and
 `6_main_manuscript_results.rmd` display the reported manuscript results /
 figures.