DOI: 10.5061/dryad.ngf1vhj1g
title: Data from: Geographic variation in leaf traits and palatability of a native plant invader during domestic expansion

description: Like alien plant invasion, range expansion of native plants may threaten
 biodiversity and economies, rendering them native invaders. Variation in
 abiotic and biotic conditions across a large geographic scale greatly
 affects variation in traits and interactions with herbivores of native
 plant invaders, which is an interesting yet mostly unexplored issue. We
 used a common garden experiment to compare defensive/nutritional traits
 and palatability to generalist herbivores of 20 native- (23.64–30.18°N)
 and introduced-range (31.58–36.87°N) populations of Reynoutria
 japonica, which is a native invader following range expansion in China. We
 analysed the relationships among herbivore pressure, climate, plant
 chloroplast haplotypes, leaf traits and herbivore performance. Of the 16
 variables tested, we observed range differences in 11 variables and
 latitudinal clines in nine variables. In general, herbivores performed
 better on the introduced plants than on the native plants and better on
 the high-latitude plants than on the low-latitude plants within the
 introduced populations. Three key traits (leaf thickness, specific leaf
 area, and C:N ratio) determined palatability to herbivores and were
 significantly associated with temperature and/or precipitation of plant
 provenance as well as with plant haplotypes but not with herbivore
 pressure. Our results revealed a causal sequence from plant-range-based
 environmental forces and genetic context to plant quality and palatability
 to herbivores in R. japonica. These findings suggest a post-introduction
 evolution of R. japonica, which may partly explain the colonization
 success of this important native, but invasive plant.
description: # Data from: Geographic variation in leaf traits and palatability of a
 native plant invader during domestic expansion
 [https://doi.org/10.5061/dryad.ngf1vhj1g](https://doi.org/10.5061/dryad.ngf1vhj1g) This dataset contains information of range, latitude, population and haplotype on a total of 20 populations of *Reynoutria japonica* from its native and introduced ranges in China. It also contains data of 9 plant traits and 7 indices of herbivore performance, as well as variables of temperature, precipitation, herbivory pressure at sampling sites. ## Description of the data and file structure The first four columns of the data (i.e. Populations, Range, Latitude, and Source_rhizome) describe the status information of *Reynoutria japonica.* Columns 5-11 (i.e. SL_larval_growth in ***mg***, SL_biomass_conversion_efficiency in ***mg/cm^2***, SL_leaf_area_consumed in ***cm^2***, SE_larval_growth in ***mg***, SE_biomass_conversion_efficiency in ***mg/cm^2***, SE_leaf_area_consumed in ***cm^2***, and Aphid_colony_size in ***no. aphids***) are the results of bioassay experiments. The data in columns 12-20 (i.e. Thickness in ***mm***, SLA in ***cm^2/g***, CN_ratio, Leaf_pH, Tannin in ***mg/g***, Lignin in ***mg/g***, Alkaloid in ***mg/g***, Coumarin in ***mg/g***, Flavonoids in ***mg/g***) are the results of the determination of plant traits and data in columns 21-24 are results of driving factors (i.e. temperature PC1, precipitation PC1, herbivore pressure, and plant haplotypes). SL and SE represent *Spodoptera litura* and *Spodoptera exigua*, respectively. We employed three indices (larval growth, leaf area consumed, and biomass conversion efficiency) to measure palatability of *Reynoutria* to caterpillars of two moth species. In late May of 2022, we purchased *S. litura* and *S. exigua* from Henan Jiyuan-Baiyun Company in China and reared them with commercial artificial diets provided by the company at 26°C with a relative humidity (RH) of 60% and a photoperiod of 14 hr:10 hr (L:D). We selected the fifth-instar larvae of *S. litura* and fourth-instar larvae of *S. exigua* for their palatability bioassay. For the bioassay of *S. litura*, we collected the third fully expanded leaf from the top of a plant, wrapped wet cotton around the petiole and then placed the leaf in a petri dish (diameter = 15 cm). We added a pre-weighed caterpillar (*W*<sub>1</sub>) to the petri dish and maintained the dish under the same conditions as for insect source rearing. After 48 hr, we removed the caterpillar from the dish and weighed it again (*W*<sub>2</sub>). We calculated caterpillar growth based on the weight gain in fresh biomass during the bioassay (*W*<sub>2</sub> – *W*<sub>1</sub>). We also quantified the leaf area consumed by the caterpillar by extrapolating from the area of leaf remnant and pre-consumption leaf area using Adobe Photoshop CC 2018 and ImageJ (v.1.53). In addition, we determined the biomass conversion efficiency of caterpillars (caterpillar growth per ln-transformed unit area of leaf consumed). We used similar procedures for the palatability bioassay of *S. exigua* except that we used the second fully expanded leaf. We evaluated growth of aphid population size to indicate *Reynoutria* palatability to *A. citricola*. In late May of 2022, we obtained commercial aphids from Henan Quanying Insect Biology Company of China and reared them on *Malus spectabilis* at 20°C with a RH of 65% and a photoperiod of 14 hr:10 hr (L:D). We first affixed a gauze-mesh cage (10 cm × 12 cm, aperture = 75 µm) on the upper portion of the stem of a plant (each cage covered apex shoots and the first fully expanded leaf) and then added 20 mature aphids in the cage and maintained them under the same conditions as for their source rearing. After nine days, we determined the aphid population size by counting the number of both adult and nymph aphids in each cage. For the palatability bioassays of caterpillars of two moth species, we tested three replicate dishes and calculated the mean value for clonal replicates from each source rhizome. For the bioassay of the aphid, we tested two replicate cages and calculated the mean value for each source rhizome. We only analysed petri dishes or cages in which caterpillars or aphids were alive and leaves were not completely consumed. We examined nine leaf traits (thickness, specific leaf area, carbon-to-nitrogen ratio, lignin, tannins, alkaloids, coumarins, flavonoids, and pH) that are putatively associated with leaf palatability to generalist herbivores. In late May of 2022, we collected the first and the fourth to seventh fully expanded leaves from the top of a plant for the quantification of physical and chemical traits. We first measured leaf thickness of the five leaves with a micrometre at the same position on the leaf. All leaves were oven-dried for 72 hr at 45°C, ground into powder, and stored at −20°C. We determined specific leaf area (SLA) according to the ratio of leaf area to leaf dry weight. We quantified the leaf carbon-to-nitrogen (C:N) ratio using a Flash-11121-Series Elemental Analyzer (Thermo Finnigan, Milan, Italy). We determined leaf pH using an acidity metre calibrated with standard buffers. We measured leaf coumarin content using an enzyme-labelled instrument (Ibiogene, Shanghai, China). We quantified the contents of leaf lignin, tannins, alkaloids, and flavonoids with commercially available assay kits (Cominbio, Jiangsu, China) following the manufacturer’s protocols. For leaf thickness and SLA, we tested three clonal replicates and calculated the mean value for each source rhizome from each site. For measurements of other traits, we had only one replicate sample for each source rhizome because we mixed leaf samples of three clonal replicates to meet the mass (1.0–1.5 g) required for quantification of all chemicals. ## Sharing/Access information Data was derived from the following sources: * [https://doi.org/10.5061/dryad.ngf1vhj1g](https://doi.org/10.5061/dryad.ngf1vhj1g)