DOI: 10.5061/dryad.84h07s1
title: Data from: Rapid evolution of Medicago polymorpha during invasion shifts interactions with the Soybean looper

description: The Enemy Release Hypothesis posits that invasion of novel habitats can be
 facilitated by the absence of coevolved herbivores. However, a new
 environment and interactions with unfamiliar herbivores may impose
 selection on invading plants for traits that reduce their attractiveness
 to herbivores or for enhanced defenses compared to native host plants,
 leading to a pattern similar to Enemy Release but driven by evolutionary
 change rather than ecological differences. The Shifting Defense Hypothesis
 posits that plants in novel habitats will shift from specialized defense
 mechanisms to defense mechanisms effective against generalist herbivores
 in the new range. We tested these ideas by comparing herbivore preference
 and performance of native (Eurasia) and invasive (New World) range
 Medicago polymorpha , using a generalist herbivore, the soybean looper,
 that co-occurs with M. polymorpha in its New World invaded range. We found
 that soybean loopers varied in preference and performance depending on
 host genotype and that overall the herbivore preferred to consume plant
 genotypes from naïve populations from Eurasia. This potentially suggests
 that range expansion of M. polymorpha into the New World has led to rapid
 evolution of a variety of traits that have helped multiple populations
 become established, including those that may allow invasive populations to
 resist herbivory. Thus, enemy release in a novel range can occur through
 rapid evolution by the plant during invasion, as predicted by the Shifting
 Defense Hypothesis, rather than via historical divergence.
description: Choice assay preference
 dataBinary results of
 preference by the soybean looper in the choice assays. Within a pair, the
 genotype with the highest proportion of leaf tissue consumed was given a 1
 and the less preferred was given a 0. Also includes the longitude,
 latitude, and range the genotype was collected from.WinLose21Jan2019.csvWeight and growth data of the soybean looperThis file collection data for the genotype of the host plant, the total weight of the the loopers in the beginning of the experiment (Before), the number of loopers in the beginning (InitialLooperNumber), average weight of the loopers (BeforeIndiv), the final looper total weight (After), the number of alive loopers found (FinalLooperNumber), the final average weight of the loopers (AfterIndiv), the number of days the experiment ran (Days), the region of the host plant (Region). It also includes calculated data columns for the estimated dry weight of the average looper before (estInitDry) and after (estFinDry) the experiment, the mean daily dry weight (dailyMeanDry), and the calculated RGR (GrowthRate).InsectsHerbData.csvSubset of host plant genotypes that were used in both the choice assay and no choice assayThis file contains the hostplant genotype and its range (Type), how much of its tissue was consumed (proportion eaten), whether it is the choice assay or no choice assay value (group), the proportion consumed of the total amount of tissue available (proprotionTotEat), and a column where we averaged by the number of days of the assay (propStd). This final column was when we considered whether to compare the amount eaten in one day for the choice assay to the day average in the choice assay.compAlonePairedZ.csvUnprocessed preference dataThis is the raw data that includes some lightly processed columns at the end. The tab that says controls is the tissue used to estimate weight loss due to water loss in the tissue. the Sheet1 tab has the raw weights for the choice pairs, and columns for those values standardized for water loss. The remaining columns were just piloted methods to analyze data. The remaining tabs were for methods of analysis that were not included in the final manuscript.FoodChoiceStd6Aug2.xlsxR script used to analyze dataThis is the R code that was used for data analysis.FinalCode10Feb2019.R