Decline of honeybees and its consequences for beekeepers and crop pollination in western Nepal

Abstract

O_LIPollination service by insects is globally threatened, yet trends outside of Europe and North America are poorly understood. Therefore, in less-studied regions of the world, beekeeper records can provide valuable insights into changes in pollinator populations. C_LIO_LIWe conducted a questionnaire survey of 116 beekeepers in 10 villages in the Jumla District of western Nepal, where the native honeybee Apis cerana cerana is widely kept as a managed honeybee. We complemented the beekeeper survey with field data on insect-crop visitation, a household income survey, and an interview with a local lead beekeeper. C_LIO_LI76% of beekeepers reported declines in the Apis cerana cerana population. 86% experienced declines in honey yield per hive, and 78% reported declines in the number of beehives per beekeeper. Honey yield per hive fell by 50% between 2012 and 2022, whilst the number of occupied hives decreased by 44%. Beekeepers ranked climate change and declining flower abundance as the most-important drivers of the decline. C_LIO_LIThe drastic bee declines raise concerns for the future food and economic security of this region, where honey sales contribute to 16% of total household farming income. Apis cerana cerana plays a major role in crop pollination and contributes more than 50% of all flower visits to apple, cucumber, and pumpkin. C_LIO_LITo mitigate further declines in this region, we promote the use of pollinator-friendly farming practices including more wild flowers and maintenance of native habitat areas, and well-insulated log or top-bar log hives to buffer bees against extreme temperature fluctuations, which are expected to worsen with climate warming. C_LI