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 (W₁) 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 (W₂). We calculated caterpillar growth based on the weight gain in fresh biomass during the bioassay (W₂ – W₁). 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.

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Data was derived from the following sources:

• https://doi.org/10.5061/dryad.ngf1vhj1g