Modeling the potential range expansion of larger grain borer, Prostephanus truncatus (Coleoptera: Bostrichidae)

Authors: Arthur, Franklin; Morrison, William - Rob; MOREY, AMY - University Of Minnesota

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/5/2019
Publication Date: 5/3/2019
Citation: Arthur, F.H., Morrison III, W.R., Morey, A.C. 2019. Modeling the potential range expansion of larger grain borer, Prostephanus truncatus (Coleoptera: Bostrichidae). Scientific Reports. 9(1):6862. https://doi.org/10.1038/s41598-019-42974-5.
DOI: https://doi.org/10.1038/s41598-019-42974-5

Interpretive Summary: The larger grain borer is native to Mexico and Central America, but it was accidentally introduced in Africa and has spread through sub-Saharan Africa, where it is a serious economic pest of stored corn and stored cassava. Given the destructive nature of larger grain borer in Africa, knowledge relating to the potential spread of this insect northward or southward from Central America and Africa, and eastward from Africa into tropical Asia, would be of great benefit in limiting or eliminating future infestations. We used the correlative modelling algorithm, MaxEnt, to identify global areas of potential suitability based on the climate locations with documented populations. Predictions using a model trained in Central America showed potential suitability extending north into the southern United States and southward into South America, including parts of Argentina, but predictions using a model built from African occurrences did not include those areas as suitable. However; there was general agreement in both models that large areas of the tropics in the Western Hemisphere and in Asia could support larger grain borer if it were to become established. The models also showed consistency in capturing suitability at sites not used in a given model’s development. Results can be used to establish surveillance programs to monitor for this insect in high risk areas where it is not currently found, and to proactively mitigate the biosecurity risk from larger grain borer.

Technical Abstract: Prostephanus truncatus (Horn), the larger grain borer, is a member of the family Bostrichidae, and is native to Mexico and Central America. It was accidentally introduced into Africa in late 1970s, where it quickly spread throughout the sub-Saharan region, perhaps aided by adaptation to cassava as an alternate host and the ability to persist in non-agricultural habitats. We used the correlative modelling algorithm, MaxEnt, to identify global areas of potential suitability based on the climate locations with documented populations. Predictions using a model trained in Central America showed potential suitability extending north into the southern United States and southward into South America, including parts of Argentina, but predictions using a model built from African occurrences did not include those areas as suitable. However; there was general agreement in both models that large areas of the tropics in the Western Hemisphere and in Asia could support P. truncatus if it were to become established. The models also showed consistency in capturing suitability at sites not used in a given model’s development. Results can be used to establish surveillance programs to monitor for this insect in high risk areas where it is not currently found, and to proactively mitigate the biosecurity risk from P. truncatus.