Data and code for: Hypothesis of overseas immigration of the invasive tomato leafminer, Tuta absoluta, in Japan
Data files
May 15, 2026 version files 32.10 KB
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Code_list_of_sampling_sites.csv
1.38 KB
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Flight_speed_of_T.absoluta.csv
199 B
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Isotopic_data_of_adhesive.csv
830 B
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Isotopic_data_of_Plant_T.absoluta_Blank.csv
19.02 KB
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Program_1_code.txt
2.66 KB
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Program_2_code.txt
728 B
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Program_3_code.txt
1.17 KB
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README.md
5.44 KB
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Threshold_temperature_for_T.absoluta_flight.csv
672 B
Abstract
Tuta absoluta is a major pest of tomato that first invaded Japan in 2021. However, the mechanism of its invasion remains unclear. We tested the hypothesis that this species migrates from overseas to Japan by analysing the strontium radiogenic isotope ratio 87Sr/86Sr of individuals trapped in Japan and tracing their backward migration trajectories.
In southern and western Japan, individuals with higher 87Sr/86Sr ratios than those of host plants in the Japanese trapping areas were captured simultaneously at multiple sites during periods of strong westerly winds blowing from the East Asian continent, suggesting that they had arrived from outside the study area. The endpoints of the backward trajectories for these captures were distributed across the continental regions where T. absoluta likely occurred.
The results suggest the possibility of overseas migration, thereby supporting our hypothesis. Although further studies, such as the investigation of potential source regions, are needed, this study provides an important ecological perspective for establishing effective pest management strategies for this species.
Dataset DOI: 10.5061/dryad.tmpg4f5cg
Description of the data and file structure
These files includes the raw data of Sampling sites, Strontium isotopic ratios of reference host plants, trapped insects with or without abdomen, blanks, and adhesives from sticky traps, Mass of strontium (Sr) and/or cobalt (Co) contained in host plants, trapped insects, blanks, and adhesives from sticky traps, Flight speed and Thermal threshold for T. absoluta's flight, and Program codes to make frequency figures of backward trajectory analysis.
Files and variables
File: Code_list_of_sampling_sites.csv
Description: This data is a code list of sampling sites for plants and insects.
Variables
- Code: Site code representing a sampling site for plants and insects..
- City/Town: The name of the city or town weher insects or plats were sampled. When a general location (e.g., "Southwestern part") is provided, the city or town name is not disclosed by the local government since it includes personal information on private farmers.
- Prefecture: The prefecture name of the sampling site.
- District: The district name of the sampling site.
- Region: The region in Japan where the sampling site is located.
File: Isotopic_data_of_adhesive.csv
Description: This data is Sr radiogenic isotope ratios (87Sr/86Sr) and mass of Sr detected in adhesives of sticky traps set for defferent periods.
Variables
- ID: ID of all adhesive samples analysed in this study.
- Site: Site code (see Code_list_of_sampling_sites.csv) where sticky traps were installed.
- Installation period (day): Number of days traps were set.
- Total Sr (ng) / adhesive 1 mg: Mass of Sr contained in 1 mg of adhesive.
- 87Sr/86Sr ± SE: The mean Sr isotope ratios of adhesives ± standard error.
File: Isotopic_data_of_Plant_T.absoluta_Blank.csv
Description: This data is Sr radiogenic isotope ratios (87Sr/86Sr) and mass of Sr and/or Co detected in reference host plants, trapped insects, and blanks.
Variables
- ID: ID of plants, insects, and blanks analysed in this study.
- Site: Site code (see Code_list_of_sampling_sites.csv) where plants and insects were collected.
- Species: The scientific names of plants and insects.
- Collection date: Date of collecting plants and insects.
- Type: Sample type of plants (calutivated or wild), insects (whole body or abdomen removal), and blanks (blank).
- Latitude (°N): Latitude of the collection site for plants and insects.
- Longitude (°E): Longitude of the collection site for plants and insects.
- Sr (ng): Mass of Sr contained in approximately 30 mg of leaf tissue, an individual of T. absoluta, and a blank.
- Co (ng): Mass of Co contained in an individual of T. absoluta and a blank.
- 87Sr/86Sr ± SE: The mean Sr isotope ratios of reference host plants, trapped insects, and blanks ± standard error.
File: Program_1_code.txt
Description: The initial program to make frequency Figures 4–6 is shown.
Variables
- Program 1: This shell program repeatedly calculates a single trajectory from a specified location (trap site) with different starting heights and times for a single date.
File: Program_2_code.txt
Description: The second program to make frequency Figures 4–6 is shown.
Variables
- Program 2: This shell program removes an invalid trajectory from a trajectory list by a program extract_endpoint_tempf_11degree.exe and counts frequency of terminal point of valid trajectories in each grid cell of 0.25 by 0.25 degree by trajfreq.exe. An output file was opened by the open-source Quantum GIS software to visualize a frequency map without invalid plots located over the sea.
File: Program_3_code.txt
Description: The final program to make frequency Figures 4–6 is shown.
Variables
- Program 3: This program is C source codes of extract_endpoint_tempf_11degree.exe which is used by Program 2. It removes nodes of the invalid trajectories involving ambient temperatures below the threshold (11 °C).
File: Threshold_temperature_for_T.absoluta_flight.csv
Description: This data is the minimum air temperature required for continuous flight of T. absoluta.
Variables
- Observation order: The order in which insect flight behavior was observed.
- Temperature (°C): Temperature inside an incubator in which insects were placed.
- Wing-flapping activity: Insect wing-flapping behavior was evaluated in three categories (continuous, intermittent, stop).
File: Flight_speed_of_T.absoluta.csv
Description: This data is free flight speed of T. absoluta.
Variables
- ID: ID of insects tested in this experiment.
- Flight distance (m): Straight-line distance between the starting point and ending point of flight.
- Flight duration (s): Time from the start of flight to landing at the ending point.
- Flight speed (m/s): Quotient of flight distance and flight duration.
Code/software
After executing the files of Program_1_code.txt, Program_2_code.txt, and Program_3_code.txt, the final output file was opend in the open-source Quantum GIS software (QGIS), version 3.38.0. to visualize the spatial distribution of backward trajectories.