Vol. 6, Issue 2, Part D (2024)

The growth of water strategy in Drosophila species has not been studied clearly in Nepal. So, an investigation was carried out to understand the growth mechanisms of water adaptive strategy in D. nepalensis. Samples of D. nepalensis (100-150) collected from different parts of high Himalayas during November 2018-January 2019. The study was carried out in the Entomology laboratory of Agriculture and Forestry University, Chitwan, Nepal. The cultures of the insects were based at low density (60-70 eggs per vial; egg vials were 40 × 100 mm in size) with the cornmeal-yeast-agar medium at 15°, 21°, and 25°C and 65±1% relative humidity in a temperature-and humidity-controlled incubator for five generations before experimental analysis. Required data for climatic variation were obtained from the meteorological department, Nepal government. Study revealed that the relative abundance of D. nepalensis has a transformation in relative humidity along an altitudinal gradient in the Western Himalayas. Thus, dehydration tolerance evolved as a common physiological mechanism to support survival under desiccation stress in D. nepalensis.