Response of foragers of the giant Himalayan honey bee, Apis laboriosa, to microclimates in agro-net and climate control greenhouses

Abstract

The giant honey bee Apis laboriosa is endemic in the high-elevation zone of the Himalaya extending from central to eastern belt and its adjacent mountain ranges. Its abundance is however reported to decline in recent decades. The present study aims to find out the favourable microclimate for foraging activity of A. laboriosa. Therefore, to explore the response of foragers to ambient temperature, relative humidity and sunlight intensity, experiments were conducted in captivity using two types of greenhouses: agro-net and climate control greenhouse. One colony of a combless cluster in each greenhouse was monitored for a period of 22 days. Monitoring was done by counting the number of foragers on honey, sugar syrup and forage plants at an interval of 1 hour. The microclimate of the greenhouses differs in sunlight intensity and relative humidity. Principal component analysis showed that the foraging activity is positively associated with sunlight intensity and relative humidity and is negatively associated with ambient temperature. Higher number of active foragers in the climate control greenhouse shows its relative humidity and sunlight intensity as favourable for foraging activity of A. laboriosa compared to the agro-net greenhouse. The result is also indicative of possible impact of change in sunlight intensity and relative humidity on the foraging activity of A. laboriosa that may affect pollination of the native plants and honey production.