Influence of abiotic factors on seasonal and non-seasonal emergence of Tasar silkworm, Antheraea mylitta Drury

Aim: The present study was carried out to introspect the effect of temperature, humidity and rainfall on the emergence of Antheraea mylitta Drury. Methodology: An experiment on seasonal and non-seasonal emergence was carried out in 2019 and 2020 at Kathikund and Kharsawan of Jhakhand, India. Meteorological parameters (temperature, humidity and rainfall) were noted twice daily. Similarly number of adult moths emerged were age-graded and segregated as male and female. They were counted twice in a day within the grainage buildings (preservatory of seed cocoons). Results: The emergence of Antheraea mylitta varied month wise following: June to September, March to May, and November to February. Although the emergence of male individuals was more compared to females, no significant difference was observed statistically. Further increase in rainfall (57%) – humidity (15%) triggered more non-seasonal emergence of females. A strong positive correlation between humidity and rainfall with the emergence of adult moths compared to temperature throughout the year across both the seasonal (June-October) and non-seasonal (November-May) months was observed. The erratic/non-seasonal emergence was strongly correlated with humidity (0.75) compared to rainfall (0.32) and temperature (0.19). Daily emergence differed significantly (p<0.01) between the seasonal and non-seasonal months. Interpretation: During seasonal months, the number of adult moths emerged remained almost constant; however in non-seasonal months, the pattern of adult emergence exhibited a non-linear interrupted by sudden intervals of zero emergence. The intervals corresponded significantly to the effect of humidity and rainfall (p<0.001), however, no significant effect of temperature (p>0.05) was observed. Key words: Abiotic factors, Antheraea mylitta, Seasonal emergence, Tasar silkworm