DOI: 10.5061/dryad.ksn02v716
title: Data from: Evolution of defence and herbivory in introduced plants - testing enemy release using a known source population, herbivore trials and time since introduction

description: The enemy release hypothesis is often cited as a potential explanation for
 the success of introduced plants; yet empirical evidence for enemy release
 is mixed. We aimed to quantify changes in herbivory and defence in
 introduced plants while controlling for three factors that might have
 confounded past studies: using a wide native range for comparison with the
 introduced range, measuring defence traits without determining whether
 they affect herbivore preferences, and not considering the effect of time
 since introduction. The first hypothesis we tested was that introduced
 plants will have evolved lower levels of plant defence compared to their
 source population. We grew South African (source) and Australian
 (introduced) beach daisies (Arctotheca populifolia) in a
 common-environment glasshouse experiment and measured seven defence
 traits. Introduced plants had more ash, alkaloids and leaf hairs than
 source plants, but were also less tough, with a lower C:N ratio and less
 phenolics. Overall, we found no difference in defence between source and
 introduced plants. To determine whether the feeding habits of herbivores
 align with changes in defence traits, we conducted preference feeding
 trials using five different herbivore species. Herbivores showed no
 overall preference for leaves from either group. The second hypothesis we
 tested was that herbivory on introduced plant species will increase
 through time after introduction to a new range. We recorded leaf damage on
 herbarium specimens of seven species introduced to Eastern Australia, and
 three native control species. We found no change in the overall level of
 herbivory experienced by introduced plants since arriving in Australia.
 Conclusion: In the field of invasion ecology we need to rethink the
 paradigm that species introduced to a new range undergo simple decreases
 in defences against herbivores. Instead, plants are likely to employ a
 range of defence traits that evolve in both coordinated and opposing ways
 in response to a plethora of different biotic and abiotic selective
 pressures.
description: Data for the six leaf traits (leaf toughness, ash, alkaloids,
 phenolics, carbon to nitrogen ratio and leaf hairs) were collected using
 standard protocols from South African source and Australian introduced
 <em>Arcthotheca populifolia </em>grown in a glasshouse at
 UNSW. Further methods are available in the published manuscript.
 Data for herbivore preference were collected by offering four
 herbivore species [green garden looper caterpillar (<em>Chrysodeixis
 </em>sp<i>.</i>), garden snail (<i>Cornu
 aspersum</i>), grey field slug (<i>Deroceras
 reticulatum</i>) and lily caterpillar (<i>Spodoptera
 picta</i>)] a choice of a South African source leaf or an Australian
 introduced leaf and then measuring the leaf damage. Data were also
 gathered by counting the number of red spider mites (<i>Tetranychus
 urticae</i>) on the two groups of plants. Further methods are
 available in the published manuscript. Data for
 herbivory through time were obtained by recording the percent of leaf area
 lost in herbarium specimens of seven species introduced to eastern
 Australia. Further methods are available in the published
 manuscript.
description: There are data for four Australian populations and one South
 African population. This is because we used genetic methods to identify
 the South Afrcian source population for comaprison with the introduced
 Australian plants. More details are available in:
 Brandenburger, C.R., Sherwin, W.B., Creer, S.M., Buitenwerf, R., Poore,
 A.G., Frankham, R., Finnerty, P.B. & Moles, A.T. (2019) Rapid
 reshaping: the evolution of morphological changes in an introduced beach
 daisy. <i>Proceedings of the Royal Society B,</i>
 <b>286,</b> 20181713. (https://doi.org/10.1098/rspb.2018.1713)