DOI: 10.5061/dryad.zw3r228cg
title: Experimental warming increases the vulnerability of high-elevation plant populations to a specialist herbivore

description: Ongoing climate change may impact alpine plant populations via both direct
 effects of increased temperature and climate-driven changes in
 interactions between plants and other organisms, such as insect
 herbivores. Rates of herbivory in high-elevation environments are
 predicted to increase with warmer temperatures, which may also lead to
 changes in morphological and physiological traits that influence plant
 resistance. Yet, we currently know little about how temperature-mediated
 changes in traits will impact alpine plant vulnerability to herbivores, as
 well as the extent to which populations from high-elevation environments
 might need to rapidly adapt to increasing herbivore pressure with rising
 temperatures. We assessed the effect of experimental warming on the
 relative vulnerability of populations of the alpine plant Arabis alpina
 from different elevations to a specialist herbivore. Herbivore performance
 was measured on plants from nine populations grown in climate chambers at
 two temperatures, representing low (warm) and high (cold) elevations. We
 also measured changes in putative drivers of performance: plant
 phenological, chemical and defence traits. Assuming populations would be
 adapted to local climates and levels of herbivory, we predicted that
 low-elevation populations would be more resistant to herbivores under
 warmer temperatures than high-elevation populations. We found reduced
 performance of a specialist herbivore on A. alpina grown under warm rather
 than cold conditions, though this effect varied with elevation. Larvae
 grew faster on high-elevation populations than low-elevation populations
 when grown under warm temperatures, whereas similar growth rates were
 observed for plants grown under colder temperatures, consistent with plant
 adaptation to the lower existing herbivore pressure in cold,
 high-elevation environments. Regression analyses suggested that polar
 metabolite variation explained more variance in larval performance than
 changes in defensive glucosinolates or morphological traits. Our results
 suggest that although physiological responses to warming may increase the
 resistance of cold-adapted plants to herbivory, populations from different
 elevations may differ in their interactions with herbivores under climate
 warming. Without genetic adaptation, existing physiological responses of
 high-elevation populations to warmer temperatures may leave these
 populations vulnerable to the increases in herbivore pressure predicted
 under climate change.
description: The dataset for this manuscript consists of multiple sets of data
 from three separate experiments (initial phenology experiment, main
 experiment 1 and main experiment 2) described in the publication.
 Experimental data such as larval mass and plant trait measurements are
 given, as well as amounts of defence compounds (glucosinolates) and polar
 metabolites. The chemical data has been processed as described in the
 manuscript text to remove erroneous or unreliable compound
 quantifications.
description: The data files are provided as CSV files ready to load into R
 statistical software. Additional text files for each experimental dataset
 explain the column headings used in CSV files. No specific programs or
 software are needed to open any of the datafiles.