Pollinators of mango-Diversity, dynamics and ecosystem services

Abstract

Majority of horticultural crops including fruits, vegetables, spices and plantations are entomophilic and depend on different kinds of insects for pollination. Many a time the contribution of pollinators is overlooked and the production packages of commercial horticulture are not giving due attention to the safety and sustainability of pollinators in crop ecosystems. At ICAR-Indian Institute of HorticulturalMResearch, Bengaluru systematic studies are being conducted since 2010 to identify potential pollinators of mango, guava, onion and watermelon and their role in fruit/seed set. Besides documenting species diversity, shifts in pollinator community structure in relation to crop phenology, variety and climate variables were studied. In mango, pollinator profile across major mango belts of the country covering the Konkan region of Maharashtra, Uttar Pradesh, Andhra Pradesh, Telangana, Karanataka and Tamil Nadu was recorded. It was found that three Dipteran species viz., Chrysomya megacephala, Eristalinus arvorum and Stomorhina discolor and two wild bee species viz., Apis florea and Tetragonula iridipennis are important pollinators of mango compared to conventional hive bees. It was established that absence of insect pollinators lead to a reduction in fruit set ranging from 70-90 per cent in different mango varieties. Thermal tolerance of major pollinator species was also worked out and C. megacephala was found to forage at wider range of temperatures compared to other species. A mass multiplication technology was standardized to produce these pollinators in large numbers and augment natural populations in the field. In onion and watermelon, native honey bee species viz., Apis cerana, A. dorsata and A. florea are major pollinators. Impact of different species on seed and fruit set was worked out. Realising the economic importance and ecosystem services provided by native pollinator fauna, strategies for conservation and efforts needed to incorporate them as essential inputs of horticulture are discussed.