PATTERNS OF STARVATION AND DESICCATION TOLERANCE IN DROSOPHILA-BIPECTINATA AND DROSOPHILA-MALERKOTLIANA

Data on mean survival times for starvation tolerance and desiccation tolerance revealed significant differences for three Indian geographical populations of D. bipectinata and D. malerkotliana. The lack of differences between two successive generations of various isofemale lines of D. bipectinata and D. malerkotliana populations suggested that these physiological traits were genetically controlled. The north Indian populations of D. bipectinata and D. malerkotliana revealed significant higher desiccation tolerance while the southern populations revealed significantly higher survival tolerance. It can be argued that the south Indian populations of D. bipectinata and D. malerkotliana which lived in hot and humid environment throughout the year were poorly protected against desiccation but displayed higher starvation tolerance due to higher metabolic rate at increased ambient temperature. Thus, Indian geographical populations of D. bipectinata and D. malerkotliana revealed adaptively maintained genetic divergence for starvation and desiccation tolerance.