Spatio and temporal variations in population abundance and distribution of peach fruit fly, Bactrocera zonata (Saunders) during future climate change scenarios based on temperature driven phenology model

The peach fruit fly, Bactrocera zonata (Saunders) (Diptera: Tephritidae) is a poylphagous and serious insect pest of horticultural crops. The purpose of study was to understand the spatial and temporal variations in population abundance and distribution of B. zonata in response to climate change-based variations in temperature across the India. To examine the likely possibilities of changes in abundance and distribution of B. zonata, temperature driven process based phenology models were linked with climatic data of multiple General Circulation Model (eight models) and climate change scenarios (RCP 2.6, 4.5, 6.0 and 8.5) using the Insect Life Cycle Modeling (ILCYM) software. The risk indices (establishment, generation, and activity index) were mapped and quantified the changes in respect to locations, scenarios, models and times (2050 & 2070). The risk indices results revealed that, 1.73 (0.8–1.0 establishment risk), 14.15 (>16 high abundance) and 59.69% (>8.0 generation per year) area is projected to be highly suitable for B. zonata regarding establishment, abundance and generation indices, respectively in India under current climatic conditions. In spite of decreased permanent establishment (Establishment Risk Index > 0.6) in future climatic conditions, it is predicted that abundance and generation indices would increase in all the locations of the country. The variation in the results due to use of multiple GCM-scenario combinations suggested that choice of GCM and scenario combinations have impact on future prediction of the species. Overall, results indicate that B. zonata would be significant threat to horticultural crops in India. Therefore, present findings are of immensly useful to provide important information to design integrated pest management strategies and phytosanitary measurements for local, regional and national level to restrain the insect pest activity across different layers.