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From Twitter

10 June 2024
Citizen Science
Prof. Francesco Nardi (University of Siena) and Prof. Rossella Annoni (junior high school G. Falcone, Cassina de' Pecchi, Milan) have been working together, this past year, with class 2D (12-13 years old pupils) on Popillia within the context of the ...
29 May 2024
Pest management
Project reports
Since 2023, the village of Kloten north of Zurich is not only famous for the Zurich Airport and for having a great ice hockey team, but also for harboring the first Popillia population in Europe north of the Alps. In summer and autumn of 2023, huge e...
29 November 2023
Citizen Science
SPOTTERON designed a folder for IPM Popillia for the Italian Citizen Science Conference in Pisa, which we attended last weekend. This folder serves as an introduction to the project for fellow Citizen Science initiatives and individuals potentially i...
Predicting the probability of Japanese beetle establishment  © INRAE, Davide Martinetti &  Leyli Borner Predicting the probability of Japanese beetle establishment

Predicting the probability of Japanese beetle establishment in Europe: the first building block of a risk-based surveillance strategy

As we've said before, a good strategy for early detection of an invasion is to consider the risk of invasion. By modelling the environmental suitability of Europe for the Japanese beetle (Popillia japonica) and therefore the risk of its establishment, our INRAE team has laid the first building block of a surveillance strategy. This work has recently been published (Borner et al., 2023; and we describe the main results here.

Is continental Europe suitable for the Japanese beetle to survive and persist in the long term?

To answer this question, we built a database of beetle distribution data and environmental predictors such as climate, land use and soil characteristics. Most of the data on Japanese beetle presence came from the citizen science platform (77%), and some were collected in the field by partners Regione Piemonte and Servizio fitosanitario della Sezione dell'agricoltura (SFTi). Combining these data, we built a species distribution model, calibrated on native and long-invaded areas (Japan, North America and the Azores), which predicts the probability of beetle presence based on local environmental conditions. We assessed the performance of the model in native and long-invaded areas by comparing the predictions with data set aside from the model training. We also compared our predictions with the latest official US invasion status. We then projected this well-calibrated and powerful model to Europe to map the environmental suitability for the Japanese beetle there.

What are the predictions for the probability of establishment in Europe?

We predicted that 63% of continental Europe would not be suitable for the Japanese beetle in the long term. However, central Europe is almost entirely suitable, with several suitable areas nestled in an area of low suitability (S1). In this low suitability area, the establishment of the beetle cannot be ruled out. The most suitable regions include the current infested area, stretching from the foothills of the Alps to the northern Balkans, and another on the eastern shores of the Black Sea. Similar regions exist in countries such as France, Germany, Austria, Switzerland, Belgium and the Netherlands. Only 1% of these suitable areas are currently infested. 

To summarise: Continental Europe is suitable for the Japanese beetle, especially Central Europe. The potential for expansion of the invasion is important, both near and far from the current infested areas.

What does it mean for surveillance strategies?

Estimating and mapping the environmental suitability of Europe for the Japanese beetle allows the likelihood of establishment to be incorporated into surveillance strategies. This gives an idea of how likely it is that the beetle would persist in the long term if it were to arrive in a particular region. This allows sites to be prioritised in surveillance strategies. The suitability maps also highlight the importance of considering passive dispersal in surveillance strategies, which is also part of the INRAE team's work, which was presented at the ECE Congress.

Find out more:

Borner L, Martinetti D, Poggi S (2023) A new chapter of the Japanese beetle invasion saga: predicting suitability from long-invaded areas to inform surveillance strategies in Europe. Entomologia Generalis 43:951–960.

Official INRAE releases:

Interactive map of Europe's suitability for the Ja...
Conference Folder for the Citizen Science Conferen...

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 EU Flag This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 861852