DOI: 10.5061/dryad.12jm63z50
title: Analysis of the occurrence of the fall armyworm (Spodoptera frugiperda) in the winter season on the southwestern islands of Japan using the insect’s strontium radiogenic isotope ratio (87Sr/86Sr)

description: Spodoptera frugiperda, an invasive pest insect that targets maize and
 other crops, first arrived in Japan in the summer of 2019. This species
 occurs year-round in East Asian subtropical regions such as southern
 mainland China and the island of Taiwan, where the mean air temperature in
 the coldest month is above 10°C. Adults are similarly found throughout the
 year on the southwestern islands of Japan. Trap monitoring there showed
 continuous or intermittent S. frugiperda catches in the 3 winter seasons
 since 2019. However, it was difficult to distinguish between immigrants
 arriving from these neighboring areas and local individuals occurring on
 each Japanese island. In this study, the possible natal origin of captured
 insects on 5 small islands (Yonagunijima, Taramajima, Okinawajima,
 Amamioshima, and Tanegashima) was determined by investigating the
 strontium radiogenic isotope ratios (87Sr/86Sr) and comparing them with
 those of reference hosts and insects. Since trapping data and the
 87Sr/86Sr values of trapped insects didn’t support S. frugiperda’s winter
 breeding on the northernmost island, Tanegashima, further analysis was
 limited to the 4 southern islands. The 87Sr/86Sr values of reference host
 plants and reared insects on the 4 islands ranged from 0.70929 to 0.71009,
 while those of catch insects ranged from 0.70885 to 0.71090. The 87Sr/86Sr
 values of the catch insects and the reference on the 4 islands did not
 differ significantly. In addition, the monthly averages of daily mean air
 temperature in January and February 2020–2022 were above 10°C, and the
 wind direction at the surface was mostly from the northeast or northwest.
 These pieces of evidence, together with winter host availability,
 suggested that S. frugiperda occurs year-round on the islands. In other
 words, the year-round occurrence area of S. frugiperda in East Asia
 extends to the Japanese southwestern islands below Amamioshima Island.
description: # Analysis of the occurrence of the fall armyworm, Spodoptera frugiperda,
 in the winter season on the southwestern islands of Japan using the
 insect’s strontium radiogenic isotope ratio (87Sr/86Sr)
 [https://doi.org/10.5061/dryad.12jm63z50](https://doi.org/10.5061/dryad.12jm63z50) ## Author Information: Naoya Hidaka1, Sachiyo Sanada-Morimura1, Gaku Akiduki1, Takashi Oyadomari2, Shinta Higa2, Kunio Kinjo2, Yuuki Ikenoue3, Ki-Cheol Shin4, Ichiro Tayasu4, Akira Otuka1 1\. Institute for Plant Protection, National Agriculture and Food Research Organization, Koshi, Kumamoto, 861-1192 Japan. 2\. Okinawa Prefectural Plant Protection Center, Naha, Okinawa, 902-0072 Japan. 3\. Kagoshima Prefectural Institute for Agricultural Development, Minami-Satsuma, Kagoshima, 899-3401 Japan. 4\. Research Institute for Humanity and Nature, Kyoto, Kyoto, 603-8047 Japan. ## Correspondence: Naoya Hidaka, Institute for Plant Protection, National Agriculture and Food Research Organization, Kumamoto, Japan. Email: [hidakan509@affrc.go.jp](mailto:hidakan509@affrc.go.jp) ## Information about funding sources that supported the collection of the data: The research program on the development of innovative technology grants (JPJ007097) from the Project of the Bio-oriented Technology Research Advancement Institution ## Data & File overview ### File List: 1\. Catch number of S.frugiperda.csv 2\. Sr isotope ratios of reference.csv 3\. Sr isotope ratios of caught insects.csv 4\. Daily wind direction data.csv 5\. Wind direction frequency data.csv These files are included the raw data of catch number of S. frugiperda, Strontium isotope ratios of reference host plants and reared insects, Strontium isotope ratios of caught insects, Daily wind direction, and wind direction frequency. Relationship between files, if important: None Additional related data collected that was not included in the current data package: None Are there multiple versions of the dataset? No A. If yes, name of file(s) that was updated: NA i. Why was the file updated? NA ii. When was the file updated? NA \######################################################################### DATA-SPECIFIC INFORMATION FOR: Catch number of S.frugiperda.csv This data is the catch number of S. frugiperda on each island to monitor this species occurrence in winter. 1\. Number of variables: 5 2\. Number of cases/rows: 144 3\. Variable List: \* Island: Name of the island where the sampling site was located. \* Sampling_date: Date on which S. frugiperda were sampled from pheromone traps. \* Number_of_traps: Number of pheromone traps set. \* Catch_number: Number of S. frugiperda caught by pheromone traps. \* Catch_number_per_trap: Average number of S. frugiperda caught per trap. 4\. Missing data codes: None 5\. Specialized formats or other abbreviations used: None 6\. Note: None \######################################################################### DATA-SPECIFIC INFORMATION FOR: Sr isotope ratios of reference.csv This data is strontium radiogenic isotope ratios (87Sr/86Sr) of reference samples (host plants and reared S. frugiperda adults) on each island. 1\. Number of variables: 4 2\. Number of cases/rows: 20 3\. Variable List: \* Island: Name of the island where the sampling site was located. \* Sample: Type of reference sample (Host plant / Reared insect). \* Latitude, Longitude: Latitude and Longitude where the sampling site was located. \* 87Sr/86Sr_of_reference: The value of 87Sr/86Sr of the reference sample. 4\. Missing data codes: None 5\. Specialized formats or other abbreviations used: None 6\. Note: None \######################################################################### DATA-SPECIFIC INFORMATION FOR: Sr isotope ratios of caught insects.csv This data is strontium radiogenic isotope ratios (87Sr/86Sr) of caught S. frugiperda adults in winter on each island. 1\. Number of variables: 3 2\. Number of cases/rows: 64 3\. Variable List: \* Island: Name of the island where the sampling site was located. \* Sampling_date: Date on which insects (S. frugiperda) were sampled from pheromone traps. \* 87Sr/86Sr_of_caught_insects: The value of 87Sr/86Sr of the caught insect sample (S. frugiperda). 4\. Missing data codes: None 5\. Specialized formats or other abbreviations used: None 6\. Note: None \######################################################################### DATA-SPECIFIC INFORMATION FOR: Daily wind direction data.csv This is wind direction data in the coldest month (January and February) 2020-2022. 1\. Number of variables: 8 2\. Number of cases/rows: 178 3\. Variable List: \* Year/Month/Day: Date (year, month and day) of observation. Only January and February of 2020-2022 are indicated. \* Yonagunijima Is./Taramajima Is./Okinawajima Is./Amamioshima Is./Tanegashima Is.: Wind direction is indicated on each island. 4\. Missing data codes: None 5\. Specialized formats or other abbreviations used: N: North / NNE: North-northeast / NE: Northeast / ENE: East-northeast / E: East / ESE: East-southeast / SE: Southeast / SSE: South-southeast / S: South / SSW: South-southwest / SW: Southwest / WSW: West-southwest / W: West / WNW: West-northwest / NW: Northwest / NNW: North-northwest 6\. Note: This data is obtained from the Japan Meteorological Agency. Latitude and Longitude of weather stations where wind direction data were observed on each island is below. Yonagunijima Is.(Station name: Yonagunijima): 24.467°N, 123.010°E Taramajima Is.(Station name: Nakasuji): 24.653°N, 124.675°E Okinawajima Is.(Station name: Naha): 26.207°N, 127.687°E Amamioshima Is.(Station name: Kasari): 28.430°N, 129.712°E Tanegashima Is.(Station name: Tanegashima): 30.720°N, 130.982°E \######################################################################### DATA-SPECIFIC INFORMATION FOR: Wind direction frequency data.csv This is wind direction frequency data in the coldest month (January and February) 2020-2022. 1\. Number of variables: 18 2\. Number of cases/rows: 15 3\. Variable List: \* Island: Name of the island where the weather station is located. \* Year: Year of observation (2020-2022). \* N/NNE/NE/ENE/E/ESE/SE/SSE/S/SSW/SW/WSW/W/WNW/NW/NNW: Frequency value (%) of each wind direction. 4\. Missing data codes: None 5\. Specialized formats or other abbreviations used: N: North / NNE: North-noutheast / NE: Northeast / ENE: East-northeast / E: East / ESE: East-southeast / SE: Southeast / SSE: South-southeast / S: South / SSW: South-southwest / SW: Southwest / WSW: West-southwest / W: West / WNW: West-northwest / NW: Northwest / NNW: North-northwest 6\. Note: This data is obtained from the Japan Meteorological Agency. Latitude and Longitude of weather stations where wind direction data were observed on each island is below. Yonagunijima Is.(Station name: Yonagunijima): 24.467°N, 123.010°E Taramajima Is.(Station name: Nakasuji): 24.653°N, 124.675°E Okinawajima Is.(Station name: Naha): 26.207°N, 127.687°E Amamioshima Is.(Station name: Kasari): 28.430°N, 129.712°E Tanegashima Is.(Station name: Tanegashima): 30.720°N, 130.982°E \######################################################################### ## Sharing/Access information The Japan Meteorological Agency ([https://www.jma.go.jp/jma/indexe.html)](https://www.jma.go.jp/jma/indexe.html\))