The potential global distribution and voltinism of the Japanese beetle (Coleoptera: Scarabaeidae) under current and future climates

Authors: Kistner-Thomas, Erica

Submitted to: Journal of Insect Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/18/2018
Publication Date: 3/22/2019
Citation: Kistner-Thomas, E.J. 2019. The potential global distribution and voltinism of the Japanese beetle (Coleoptera: Scarabaeidae) under current and future climates. Journal of Insect Science. 19(2):1-13. https://doi.org/10.1093/jisesa/iez023.
DOI: https://doi.org/10.1093/jisesa/iez023

Interpretive Summary: The Japanese beetle, Popillia japonica, is a highly invasive pest of turf, landscapes, and horticultural crops in the United States. Originally from Japan, this insect has invaded vast areas of North America over the last hundred years and has recently invaded mainland Europe. With over 300 reported host plants, this highly polyphagous insect thrives in both urban and agricultural landscapes. Climate change is expected to exacerbate agricultural losses from the Japanese beetle by lengthening its growing season and expanding its potential geographic distribution. In this study, a process-oriented bioclimatic niche model for the Japanese beetle was developed in order to examine its potential global distribution under both current climatic conditions and possible future climate under the RCP 8.5 emission scenario for the year 2050. Model outputs indicate that climate change will likely enable this pest to expand its range northward into Canada and northern Europe due to projected rising winter temperatures. This information will assist pest managers and plant biosecurity agents in determining which regions are most vulnerable to Japanese beetle invasion as well as areas under increasing plant health risks from already established populations in light of climate change.

Technical Abstract: The Japanese beetle, Popillia japonica (Newman; Coleoptera: Scarabaeidae), is a severe invasive insect pest of turf, landscapes, and horticultural crops. It has spread to every Northern Hemisphere continent, most recently to mainland Europe. The distribution and voltinism of P. japonica will undoubtedly change as a consequence of climate change, adding additional challenges to managing this species. To assess this, a process-oriented bioclimatic niche model for P. japonica was developed to examine its potential global distribution under current (1981-2010) and projected climatic conditions (2040-2059) using one emission scenario (RCP 8.5) and two global climate models, ACCESS1-0 and CNRM-CM5. Simulated changes in cumulative growing degree-days were also examined. The model agreed well with all credible current distribution data. Model projections indicate a strong possibility of further range expansion throughout mainland Europe under both current and future climates. In North America, projected increases in temperature would enable northward range expansion across Canada while simultaneously reducing southern range limits in the United States. In Europe, alone, suitable range for P. japonica would increase by 23% by mid-century, especially across portions of the UK, Ireland, and Scandinavia. Under the RCP 8.5 scenario, cumulative growing degree-days increased, thereby reducing the probability of bi-annual life cycles in northern latitudes where they are commonly observed, including Hokkaido, Japan, northeastern portions of the United States and southern Ontario, Canada. The results of this study highlight several regions of increasing and emerging risk from P. japonica that should be considered routinely in ongoing biosecurity and pest management programs.