DOI: 10.5061/dryad.vmcvdnd2w
title: Climate matching models for Ceratapion basicorne (Coleoptera: Apionidae), a biocontrol agent of yellow starthistle

description: Ceratapion basicorne (Illiger) (Coleoptera: Apionidae), a weevil native to
 Europe and western Asia, shows promise for enhancing the control of yellow
 starthistle (Centaurea solstitialis L.), an invasive annual forb in the
 western U.S. However, a paucity of data on this biocontrol agent’s
 environmental constraints has made it difficult to assess the suitability
 of potential release locations. Climate matching models were developed for
 C. basicorne to help identify areas of the western U.S. with similar
 climates to the source area of breeding colonies being used for releases
 (home location). The models used climate variables derived from daily
 estimates of minimum temperature, maximum temperature, precipitation, and
 soil moisture for a 30-year period spanning 1991−2020 at 1 km2 resolution.
 Of the areas where C. solstitialis is known to occur, the Central
 California Foothills, Eastern Cascades Foothills, Columbia Plateau, and
 mountainous parts of northcentral Utah had the most similar climates to
 the home location. Of these areas, the Eastern Cascades foothills in
 northeastern California and the Wasatch Range in Utah occurred at a
 similar latitude as the home location, which may be important to consider
 if C. basicorne has photoperiodic diapause. The least similar
 climates occurred in wet coastal regions, high-elevation (cold) mountains,
 and hot deserts; however, C. solstitialis has not been detected in most of
 these areas. The development of process-based models for predicting the
 establishment of this agent will require a more detailed understanding of
 the agent’s requirements for development and survival.
description: The details of the Methods are described in the publication and
 summarized below. The README file provides more details about the data and
 file structure. Climate data: climate matching models
 for <em>C. basicorne </em>used averages of minimum and maximum
 temperatures (<em>T<sub>max</sub></em><sub>
 </sub>and <em>T<sub>min</sub></em>,
 respectively), precipitation, and soil moisture for a 30-year period
 spanning 1991−2020. Daily temperature and precipitation data were derived
 from the Daymet dataset for North America at 1 km2 resolution (https://daymet.ornl.gov/getdata, accessed 17 May 2024) and the E-OBS dataset for Europe at 0.1° deg resolution (<em>ca. </em>11.1 km<sup>2</sup>; https://surfobs.climate.copernicus.eu, accessed 13 Jul 2022). Daily soil moisture estimates at the first 5 cm depth were derived from the Simple Terrestrial Hydrosphere model, version 2 (SiTHv2) at 0.1° deg resolution. SiTHv2 data were downscaled to 1-km<sup>2</sup> resolution for the western U.S. to match the resolution of Daymet data. All datasets were temporally aggregated to a weekly and monthly resolution for modeling. See the README file for more details. County-level detections for yellow starhistle: these were estimated from GBIF and EDDMaPS data.
description: # **Climate matching models for *Ceratapion basicorne* (Coleoptera:
 Apionidae), a biocontrol agent of yellow starthistle** Access this dataset
 on Dryad:
 [https://doi.org/10.5061/dryad.vmcvdnd2w](https://doi.org/10.5061/dryad.vmcvdnd2w) Brittany Barker Questions?  [bbarker505@gmail.com](mailto:bbarker505@gmail.com){.email} or [brittany.barker@oregonstate.edu](mailto:brittany.barker@oregonstate.edu){.email} ## **Purpose** The code and files in this repository produce climate-matching models for *Ceratapion basicorne* for the western U.S. (Barker et al. 2025). ## **Description of the data and file structure** ### **Subfolders** The main folder (directory) contains the following subfolders: * `data`: all data needed for modeling (see descriptions below). * `plots`: image files (`.png` files) produced by models are saved here. Images produced by the CLIMEX-based model and Climatch models are saved to the `CLIMEX_custom` and `Climatch` folder, respectively. * `raster_outputs`: rasters (`.tif` files) produced by models are saved here. Rasters produced by the CLIMEX-based model and Climatch models are saved to the `CLIMEX_custom` and `Climatch` subfolders, respectively. * `script`: running the R script `CEBA_climMatch.R` re-produces all models, figures, and rasters presented in the manuscript (see below). ### **Data** Climate data for modeling: the CLIMEX-based model uses weekly climate data (`/data/weekly/`) whereas the Climatch model uses six bioclimatic variables (`/data/bioclim/`). For each model type, the data are split according to the 'home' location (Kilkis, Greece) and 'away' locations in the western U.S. Averages of climate for a 30-year period spanning `1991-2020` were derived from the Daymet and E-OBS datasets. In raster datasets, all locations in the western U.S. (extent: `xmin = -125.0024, xmax = -101.9945,ymin = 31.18652, ymax = 49.40551`) are at `1-km2` resolution and the coordinate reference system is WGS84 (EPSG:4326). Units are degrees Celsius for temperature (Tmin, Tmax), millimeters for precipitation, and `m3 m-3` for soil moisture. Further details about the climatic data and variables used in models can be found in the publication for this study. A summary of these datasets is below: * `/data/weekly/home/kilkis.csv`: Data for the 'home' location used for the CLIMEX-based model. The columns correspond to averages of weekly climate for Tmin, Tmax, and soil moisture (sm) (`52` weeks `x` `3` variables `=` `156` columns) (e.g., `ppt01` = precipitation of the first week of the year), as well as the average annual total precipitation (mm) (`ppt_ann`). * `/data/weekly/away/*tif:` Data for the 'away' locations used for CLIMEX-based models. There are `156` rasters corresponding to weekly estimates of Tmin, Tmax, and soil moisture (sm) (`52` weeks `x` `3` variables `=` `156` rasters), as well as an annual estimate of precipitation (`ppt_ann`). * `/data/bioclim/home/kilkis.csv`: Data for the 'home' location used for the Climatch models. The columns correspond to bioclimatic variables derived from 30-year averages of climate. These included Tmax of the warmest month (`bio5`), Tmin of the coldest month (`bio6`), annual precipitation (`bio12`), highest monthly soil moisture (`bio29`), and lowest monthly soil moisture (`bio30`). The row corresponds to the source location for *C. basicorne* in Kilkis, Greece (`latitude = 22.844, longitude = 40.994`). * `/data/bioclim/away/*tif:` Data for 'away' locations used for Climatch models (same bioclimatic variables as the home location). * `/data/YST_counties/YST_counties_9-19-24.shp:` Geospatial vector data of counties in the western U.S. where yellow starthistle has been observed. Observations were obtained from the Early Detection and Distribution Mapping System (EDDMapS, 2024) and the Global Biodiversity Information Facility (GBIF.org, 2024). A single record was retained for each county, for a total of `182` records from `11` states. The geometry type is a multi-polygon (extent: `xmin = -125.0024, xmax = -101.9945,ymin = 31.18652, ymax = 49.40551`) and the coordinate reference system is NAD83. The columns include: `STATEFP` (state FIPS code), `COUNTYFP` (U.S. county FIPS code), `NAME` (county name), `geometry` (longitude, latitude), `n_number` (number of records), and `present` [if starthistle has been detected (present) or not (absent)]. ## **Sharing/Access information** Data were derived from the following sources: * [Daymet dataset for North America](https://daymet.ornl.gov/getdata) * [E-OBS dataset for Europe](https://surfobs.climate.copernicus.eu) * [SiTHv2 global soil moisture dataset](https://data.tpdc.ac.cn/en/data/bc51e1b0-494c-4cd5-ae4d-eba6b9d2322c) * [EDDMapS database](https://www.eddmaps.org/) * [GBIF | Global Biodiversity Information Facility](https://www.gbif.org/) Citations for datasets can be found in the publication (Barker et al. 2025) ## **Code/Software** The R statistical software (version 4.3.2) was used to produce models. ### **Required R packages** The following packages must be installed: `here, tidyverse, ggspatial, rnaturalearth, sf, terra, tidyterra, Euclimatch, GA, cowplot.` ### **Instructions** (1) Clone the repository (or download the directory from Dryad). Don't move or delete any subfolders or datasets.\ (2) Open the R project (`CEBA_climMatch.Rproj`) in RStudio/Posit.\ (3) Open the R script named `CEBA_climMatch.R` in the `script` subfolder.\ (4) Install any necessary packages as listed above.\ (5) Run the R script, which produces the climate-matching models and associated outputs. ## **Acknowledgements** This work was funded by the U.S. Department of Defense Strategic Environmental Research and Development Program (U.S. Army Corps of Engineers, contract no. [RC23-3611](https://demo.serdp-estcp.mil/projects/details/48787c60-7e33-4cda-bd02-5bc31b402265/managing-yellow-starthistle-using-a-new-biocontrol-agent-an-integrative-experimental-and-geo-climatic-modeling-approach)). ## **References** Barker, B. S. 2025. Climate matching models for *Ceratapion basicorne* (Coleoptera: Apionidae), a biocontrol agent of yellow starthistle. Journal of Economic Entomology. [http:/doi.org/10.1093/jee/toae299](http:/doi.org/10.1093/jee/toae299). EDDMapS. 2024. Early Detection & Distribution Mapping System. The University of Georgia - Center for Invasive Species and Ecosystem Health. Available online at: [http://www.eddmaps.org](http://www.eddmaps.org) (accessed 19 September 2024). GBIF.org. 2024. (19 September 2024) GBIF Occurrence Download [https://doi.org/10.15468/dl.sqmyns](https://doi.org/10.15468/dl.sqmyns).