author(s)
Janak Pant and Prava Dawadi

abstract
In the local condition of Chitwan Nepal the study on morphology and capacity of Drosophila melanogaster was not investigated. Therefore, an experiment was carried out to determine morphology and capacity of Drosophila melanogaster in changing climate and variable environmental factors. Laboratory and field study of D. Melanogaster was carried out in five sample stocks that were collected from the field and at the same time evaluation in field condition was also carried out; the research was conducted from January 2022 to December 2022. Samples of D. Melanogaster with similar body size and wing structure were accumulated in the laboratory condition to determine variation in morphology (wing size) with respect to different month period artificializing similar temperature in laboratory condition as that of external environment. In the field, the samples were analyzed from the same site through where the insects collected for laboratory study, however with different elevation. The variation in morphology, i.e., size of wings (length and breadth) was studied in the laboratory while for each ten minutes the flight or climbing capacity of sample Drosophila were counted or recorded in the field. It was found that the average length and breadth of the wings of Drosophila fluctuated in variable months of the year. Longest length (with average of 3mm) and width of wings (2 mm in average) observed in the sample Drosophila during the month of June, July, October, November, and December, while shortest length of wings (2.5 mm in average) and width (1.5 mm in average) found in the month of February, March, April, May, August, and September in the similar samples of Drosophila. Higher reduced flight or climbing capacity in average (81%) were observed in the Drosophila stock samples flying at lower elevation of 150 masl (i.e., having higher CO₂) and lower reduced flight or climbing capacity in average of 30% were observed in similar sample Drosophila flying at higher elevation of 850 masl (i.e., having lower CO₂). Morphology and capacity of sample Drosophila melanogaster was found affected by variable environmental and presumed changing climate in Chitwan district of Nepal.