The current and future potential distribution of Gargaphia decoris: A biological control agent for Solanum mauritianum (Solanaceae)

Abstract

The lace bug, Gargaphia decoris Drake (Hemiptera: Tingidae) is a biological control agent of the South American invasive tree Solanum mauritianum Scopoli (Solanaceae). Gargaphia decoris has been established with some success in New Zealand and South Africa. In this study, we used the climatic modelling software CLIMEX (Hearne Scientific Software Pty Ltd, Australia) to assess how current and future climatic conditions might influence the geographic distribution of the biocontrol agent in these countries and worldwide. CLIMEX parameters were based on experimental data and calibrated with distribution records from the insect’s native and non-native range. In its native range, our model predicts that G. decoris could expand its distribution into northern coastal regions of Brazil, with tropical dry summer or monsoon climate. It could also expand beyond its native range into other countries with temperate and subtropical climates, as well as several regions with tropical savanna, equatorial and monsoon climate in coastal regions. In New Zealand the greatest potential for further expansion is within the North Island, and in South Africa the expansion is limited to mostly coastal areas. In a future climate change scenario (A1B, CSIRO Mk3 2090), there is a predicted reduced distribution globally, especially for Asia, Africa, and the Americas. In Europe the climatic suitability for G. decoris will increase, with an expanded potential distribution. In South Africa the potential distribution is predicted to slightly reduce, while an expansion is predicted into the colder regions of New Zealand. These models provide a useful tool to inform future releases of G. decoris and to guide monitoring efforts within and beyond release areas.