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

Frank H Arthur,Amy C Morey,William R Morrison

doi:10.1038/s41598-019-42974-5

Abstract

Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae), is a beetle that is a member of a family that is primarily comprised of wood-boring insects, including forest insect pests. It is native to Mexico and Central America, where it has adapted to become a pest of stored maize. It was accidentally introduced into Africa in late 1970s, where it quickly spread throughout the sub-Saharan region, perhaps aided by adaptation to alternate hosts and the ability to persist in non-agricultural habitats. We used the correlative modelling algorithm, MaxEnt, to identify global areas of potential high suitability based on the climate locations with documented populations. Predictions using a model trained in Mexico + Central America showed potential high climatic 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 highly suitable. However, there was general agreement in both models that large areas of the tropics in the Western Hemisphere and in Asia have climatic conditions that could support P. truncatus if it were to become established. The models also showed consistency in capturing potential suitability at sites not used to build a given model. Results can be used as an initial guide 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.

Highlights

The larger grain borer, Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae), is native to Mexico and Central America, where it is a pest of stored maize though it is found in non-agricultural habitats[1,2]
The climate conditions for recorded occurrences of P. truncatus in Mexico + Central America, and Africa were similar for variables BIO3, BIO5, BIO6, and BIO12 (Table 2)
The model trained in Mexico + Central America showed a high degree of discriminatory ability based on the area under the receiver-operator curve (AUC), and closely met the expected value for the omission rate (AUC and ORMTP, see Table 3)

Summary

Introduction

The larger grain borer, Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae), is native to Mexico and Central America, where it is a pest of stored maize though it is found in non-agricultural habitats[1,2] It was accidentally introduced into east Africa and first documented in Tanzania in the late 1970s1,3. Given the destructive nature of P. truncatus in Africa, knowledge relating to the potential spread of this insect northward or southward from Mexico and Central America and Africa, and eastward from Africa into tropical Asia, as well as knowledge on climatically suitable habitats for invasion would greatly benefit efforts in limiting or eliminating future infestations by targeting detection efforts to areas where the pest is likely to establish. The extrapolation of correlative model predictions to new areas of space and time – an interest of most applications to invasive species – requires caution[23,24]

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Results

Conclusion