Impact of Neonicotinoid Insecticides on the Foraging Activity of Indian Honey Bee, Apiscerana indica (Fab.) in the Cotton Ecosystem

Abstract

Indian honey bees are the important managed pollinators of several agricultural and horticultural crops in India. At present, bee colony decline is the biggest crisis amongbeekeepers. The use of neonicotinoid insecticides is considered the prime factor, and they were found to cause a direct impact on bees by mortality and indirectly impair the foraging behavior of bees. Hence, the study aimed to assess the impact of neonicotinoids on the foraging activity of Indian honey bees. The neonicotinoids viz., imidacloprid 17.8 SL, clothianidin 50 WDG, thiamethoxam 25 WG, and thiacloprid 21.7 SC, along with organophosphate dimethoate 30 EC (chemical check) and control (no spray) were sprayed at field recommended doses on cotton crop. Foraging activity of the bees,viz.,incoming foragers with nectar and pollen load and outgoing foragers were counted at the hive entrance during the morning (09.00-11.00), afternoon (13.00-15.00), and evening (16.00-18.00) hours of the day. The data were recorded at pre-treatment count and posttreatment count on different day intervals viz., 1DAS, 3DAS, 7DAS, and 15DAS. The mean number of incoming nectar, pollen foragers, and outgoing foragers were recorded to be maximum in control than neonicotinoid-treated plots. Hence, the reduction in foraging activity may lead to areduction in the food storage area and brood area ultimately lesseningthe overall colony growth. It’s always better to avoid spraying cotton crop during the flowering period using neonicotinoids to dodge the residues even though cotton is not a food crop; meanwhile, it will safeguard the pollinators.