Data from: Herbivores and plant defenses affect selection on plant reproductive traits more strongly than pollinators

To evaluate whether plant defenses alter herbivore- and/or pollinator-mediated selection, we factorially crossed chemical defense (25 cyanogenic and 25 acyanogenic genotypes), herbivore damage (herbivore suppression) and pollination (hand-pollination). We found that herbivores weakened selection for increased inflorescence production, suggesting that large displays are costly in the presence of herbivores. In addition, herbivores weakened selection on flower size but only among acyanogenic plants, suggesting that plant defenses reduce the strength of herbivore-mediated selection.

Pollinators did not independently affect selection on any trait, although pollinators weakened selection for later flowering among cyanogenic plants. Overall, cyanogenic plant defenses consistently increased the strength of positive directional selection on reproductive traits. Herbivores and pollinators both strengthened and weakened the strength of selection on reproductive traits, although herbivores imposed ~2.7× stronger selection than pollinators across all traits.

Contrary to the view that pollinators are the most important agents of selection on reproductive traits, our data show that selection on reproductive traits is driven primarily by variation in herbivory and plant defenses in this system.

Methods

All details are in the associated manuscript. The code and data for this project are additionally available in this GitHub repository

Usage notes

Santangelo_et-al_JEB_2018_Dryad The Zipped folder contains all data and scripts necessary to reproduce the results in the manuscript. The README is contained in the zipped folder. For additional reproducibility (e.g. raw data files, processing scripts, packrat R package repository), please visit the GitHub page for James Santangelo (linked in the README).