DOI: 10.5061/dryad.9p8cz8wqk
title: Data from: Geographic distribution of terpenoid chemotypes in Tanacetum vulgare mediates tansy aphid occurrence but not abundance

description: Intraspecific variation of specialized metabolites in plants, such as
 terpenoids, are used to determine chemotypes. Tansy (Tanacetum vulgare L.)
 exhibits diverse terpenoid profiles that affect insect communities.
 However, it is not fully known whether patterns of their chemical
 composition and associated insects vary beyond the community scale. Here,
 we investigated the geographic distribution of mono- and sesquiterpenoid
 chemotypes in tansy leaves and their relationships with specific insect
 communities across Germany. We sampled tansy leaves from ten plants with
 and five plants without aphids in each of 26 sites along a north-south and
 west-east transect in Germany. Hexane-extracted metabolites from leaf
 tissues were analyzed by gas chromatography-mass spectrometry (GC-MS).
 Plant morphological traits, aphid occurrence and abundance, and occurrence
 of ants were recorded locally. The effect of plant chemotype, plant
 morphological parameters, and abiotic site parameters such as soil types,
 temperature and precipitation on insect occurrences were analyzed. Plants
 clustered into four monoterpenoid and four sesquiterpenoid chemotype
 classes. Monoterpene classes differed in their latitudinal distribution,
 whereas sesquiterpenes were more evenly distributed across the transect.
 Aphid and ant occurrence was influenced by monoterpenoids. Plants of
 monoterpenoid class 1 were colonized by aphids and ants significantly more
 often than expected by chance, whereas in other classes there were no
 significant differences. Aphid abundance was affected by soil type, and
 average annual temperature positively correlated with the occurrence of
 ants. We found significant geographic patterns in the distribution of
 tansy chemodiversity and show that monoterpenoids affect aphid and ant
 occurrence, while the soil type can influence aphid abundance. We show
 that geographic variation in plant chemistry influences insect community
 assembly on tansy plants.
description: This data was curated by collecting tansy (<em>Tanacetum
 vulgare</em>) plants from 26 sites along northwest-southeast
 transects in Germany. During the survey, GPS coordinates, abiotic site
 parameters, plants with and without aphids, ant species, and plant
 morphological data were recorded. Plants were then processed for chemical
 analysis with n-hexane extraction protocol and GC-MS analysis as described
 by Clancy et al., 2016. The plants were then clustered into chemotypes
 based on their mono- and sesquiterpenoid content by using
 "hclust" function in "factoextra" package in R.
 Different statistical analyses and tests were performed: The Discriminant
 Analysis of Principal Components (DAPC), generalized linear models,
 posthoc Tukey tests, and tanglegram of mono- and sesquiterpenoid chemotype
 trees.  All the statistical analyses were conducted in
 R, using the "hclust", "vegan", "adegenet",
 "chemodiv", "emmeans" and "car"
 packages.
description: # Data from: Geographic distribution of terpenoid chemotypes in Tanacetum
 vulgare mediates tansy aphid occurrence but not abundance
 [https://doi.org/10.5061/dryad.9p8cz8wqk](https://doi.org/10.5061/dryad.9p8cz8wqk) ## Description of the data and file structure We collected the plant morphological and insect data (e.g. plant height, stems, aphid species (**Aphid occurrence**), counts (**Me.occ**), etc.) in 26 different sites from north to south Germany. We then used the plants for chemical analysis by using gas chromatography/mass spectrometry (GC-MS). The detected terpenoids were identified by using the National Institute of Standards and Technology (NIST), Mass Spectral Library (NIST 11). The quantification of the compounds was performed based on the dilutions of the external standards: sabinene, α-pinene, linalool, methylsalicylate, β-caryophyllene, α-humulene, geraniol, and bornyl acetate at different concentrations (pmol/g). We clustered the plants (**Sample ID**) into monoterpenoid (**Monoterpenoid (MT) classes**) and sesquiterpenoid (**Sesquiterpenoid (ST) classes**) chemotype classes. Plants that were not analyzed for chemical analysis are reported as "NA" in the dataset. ## Code/Software We used "vegan", "adegenet", "chemodiv", "emmeans" and "car" packages in R