Chilo partellus is a major crop pest in Asia and Africa, and has recently spread to the Mediterranean region. Knowledge of its potential distribution can inform biosecurity policies aimed at limiting its further spread and efforts to reduce its impact in areas that are already invaded. Three models of the potential distribution of this insect have been published, each with significant shortcomings. We re-parameterized an existing CLIMEX model to address some parameter inconsistencies and to improve the fit to the known distribution of C. partellus. The resulting model fits the known distribution better than previous models, highlights additional risks in equatorial regions and reduces modelled risks in wet and extremely dry regions. We bring new insights into the role of irrigation in the potential spread of this invasive insect and compare its potential distribution with the present known distribution of its hosts. We also distinguish regions that are suitable for supporting persistent populations from those that may be at risk from ephemeral populations during favourable seasons. We present one of the first demonstrations of a new capability in CLIMEX to automatically estimate parameter sensitivity and model uncertainty. Our CLIMEX model highlights the substantial invasion risk posed by C. partellus to cropping regions in the Americas, Australia, China, Europe, New Zealand and West Africa. Its broad host range and reported impacts suggest that it should be a pest of significant concern to biosecurity agencies in these presently uninvaded regions.
Bibliographical noteFunding Information:
This work was led by InSTePP (International Science and Technology Practice and Policy), University of Minnesota, and CSIRO (Commonwealth Scientific and Industrial Research Organization), Australia, and was funded by the Bill and Melinda Gates Foundation by way of the HarvestChoice project. Thanks are due to Philip Pardey, Jason Beddow, Rob Venette and Bob Sutherst for initiating the development of the original CLIMEX model of C. partellus in 2008, to Philip Pardey and Jason Beddow for supporting the current re-parameterisation, and to Kylie Ireland and Dean Paini for comments on the draft manuscript. We also thank the four anonymous reviewers for their various comments and suggestions. The Bulletin of Entomological Research and ICIPE kindly gave us permission to reproduce figures from previous publications.
© 2016, The Author(s).
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