Climate and host plant availability impact the future distribution of the bean leaf beetle (Cerotoma trifurcata)

Abstract

The bean leaf beetle, Cerotoma trifurcata, has become a major pest of soybean throughout its North American range. With a changing climate, there is the potential for this pest to further expand its distribution and become an increasingly severe pest in certain regions. To examine this possibility, we developed bioclimatic envelope models for both the bean leaf beetle, and its most important agronomic host plant, soybean (Glycine max). These two models were combined to examine the potential future pest status of the beetle using climate change projections from multiple general circulation models (GCMs) and climate change scenarios. Despite the broad tolerances of soybean, incorporation of host plant availability substantially decreased the suitable and favourable areas for the bean leaf beetle as compared to an evaluation based solely on the climate envelope of the beetle, demonstrating the importance of incorporating biotic interactions in these predictions. The use of multiple GCM-scenario combinations also revealed differences in predictions depending on the choice of GCM, with scenario choice having less of an impact. While the Norwegian model predicted little northward expansion of the beetle from its current northern range limit of southern Ontario and overall decreases in suitable and favourable areas over time, the Canadian and Russian models predict that much of Ontario and Quebec will become suitable for the beetle in the future, as well as Manitoba under the Russian model. The Russian model also predicts expansion of the suitable and favourable areas for the beetle over time. Two predictions that do not depend on our choice of GCM include a decrease in suitability of the Mississippi Delta region and continued favourability of the southeastern United States.

Many unreported crop pests and pathogens are probably already present

“…The negative relation with distance from coast is likely to be related to import via shipping ports (Huang, Zhang, Kim, & Suarez, 2012;Liebhold et al, 2013), and supports the observation that islands report more pests than countries with land borders (Bebber, Holmes, Smith, et al, 2014). Implicitly, we can assume that the presence of the host crop indicates that the climate is suitable for the pest (Paini et al, 2016), though we acknowledge that this is not necessarily the case (Berzitis, Minigan, Hallett, & Newman, 2014). Implicitly, we can assume that the presence of the host crop indicates that the climate is suitable for the pest (Paini et al, 2016), though we acknowledge that this is not necessarily the case (Berzitis, Minigan, Hallett, & Newman, 2014).…”

Range-Expanding Pests and Pathogens in a Warming World

“…For example, the CLIMEX model uses 19 parameters describing growth and stress responses to temperature and moisture (75), whereas a model of fungal infection probability uses three temperature variables and one moisture variable (97). CLIMEX has proved particularly popular in the projections of climate change impacts on CPP range shifts (16,72,75,109).…”

“…So far, few studies have attempted to integrate host availability into CPP distribution models under climate change. Combined projections for the soybean and the bean leaf beetle (Cerotoma trifurcata) using the CLIMEX model indicate that host distribution will limit the potential pest distribution (16). This is because, despite the wide climatic tolerances of soybean (due in part to breeding of cultivars for different climates), the temperature range of the beetle, a generalist feeding on numerous hosts, is even wider.…”

Impacts of climate change and host plant availability on the global distribution of Brontispa longissima (Coleoptera: Chrysomelidae)

“…Host plants also play an important role in pest distributions by providing food and shelter, and some studies have started to consider their impact. Berzitis et al . and Da et al .…”