a1 HortResearch, PO Box 51, Lincoln, New Zealand
a2 Ensis, Private Bag 3020, Rotorua, New Zealand
The oriental fruit fly, Bactrocera dorsalis (Hendel), is a major pest throughout South East Asia and in a number of Pacific Islands. As a result of their widespread distribution, pest status, invasive ability and potential impact on market access, B. dorsalis and many other fruit fly species are considered major threats to many countries. CLIMEX™ was used to model the potential global distribution of B. dorsalis under current and future climate scenarios. Under current climatic conditions, its projected potential distribution includes much of the tropics and subtropics and extends into warm temperate areas such as southern Mediterranean Europe. The model projects optimal climatic conditions for B. dorsalis in the south-eastern USA, where the principle range-limiting factor is likely to be cold stress. As a result of climate change, the potential global range for B. dorsalis is projected to extend further polewards as cold stress boundaries recede. However, the potential range contracts in areas where precipitation is projected to decrease substantially. The significant increases in the potential distribution of B. dorsalis projected under the climate change scenarios suggest that the World Trade Organization should allow biosecurity authorities to consider the effects of climate change when undertaking pest risk assessments. One of the most significant areas of uncertainty in climate change concerns the greenhouse gas emissions scenarios. Results are provided that span the range of standard Intergovernmental Panel on Climate Change scenarios. The impact on the projected distribution of B. dorsalis is striking, but affects the relative abundance of the fly within the total suitable range more than the total area of climatically suitable habitat.
(Accepted December 14 2006)