Constructions of Life Table for Some Bi-voltine Hybrids of Mulberry Silkworm (Bombyx Mori Linn.) Under Lab Conditions

Abstract

The lab experiment entitled “Constructions of life table for some bi-voltine hybrids of mulberry silkworm (Bombyx mori Linn.) under lab conditions.” was conducted during Kharif season-2021 at Sericulture Research, Demostration and Training Unit, Department of Entomology, College of Agriculture, Sardar Vallabhbhai Patel University of Agriculture & Technology, Meerut-250110 (U.P.). Mulberry silkworm, Bombyx mori Linn. race NB4D2 x SH6 required 37 and 40 days to complete its life cycle at control temperature (25±1°C) and room temperature, respectively. There was an initial drop in survivorship (lx) followed by an intermittent steady decline with the long pauses till the formation of adult and sharp decline was observed at adult stage in both the conditions viz., control temperature (25±1°C) as well as room temperature till the end of generation. The data obtained from stage specific life table, the highest apparent mortality 17.58 was recorded at 1st instar larval stage of Bombyx Mori Linn. race NB4D2 x SH6 at control temperature (25±1°C). The summation of all the k-values, 0.30 was recorded at room temperature followed by 0.27 at control temperature (25±1°C). The data obtained from life and fertility table exhibited highest potential fecundity was 331 eggs per female at control temperature (25±1°C) and 290 eggs per female at room temperature. The value of net reproductive rate (R0), intrinsic rate of increase (r), finite rate of increase (λ) were114.33, 0.07, 1.174 at control temperature (25±1°C), respectively much better than the values obtained from room temperature. The mean length of generation (T) and annual rate of increase were 27.66 days, 3.12437874 x 1028 at control temperature (25±1°C), respectively also superior than the values obtained from room temperature.