Stage specific life table of mulberry silkworm race NB₄D₂ × SH₆ at different temperatures under laboratory conditions

The data obtained from stage specific life table the highest apparent mortality 17.58% was recorded at 1^st instar larval stage of Bombyx mori Linn. race NB₄D₂ × SH₆ and the lowest apparent mortality 1.61% was recorded in 4^th instar larval stage of Bombyx mori Linn. race NB₄D₂ × SH₆ at control temperature (25 ± 1°C). The highest value of survival fraction (S_x) 1.00 was recorded at pupal stage in hybrid cross NB₄D₂ x SH₆ of Bombyx mori Linn. at control temperature (25 ± 1°C) as well as at room temperature. The lowest value of survival fraction (S_x) 0.82 was recorded at 1^st instar larval stage of mulberry silkworm at control temperature (25 ± 1°C). The value of the generation survival fraction (S_G) 4.10 was recorded at control temperature (25 ± 1°C) and 4.12 at room temperature. The highest value of mortality survival ratio (MSR) 0.21 was recorded in 1^st instar larval stage of mulberry silkworm at control temperature (25 ± 1°C) and lowest value of mortality survival ratio (MSR) 0.02 was recorded 4^th instar larval stage of Bombyx mori Linn. at control temperature (25 ± 1°C). No mortality survival ratio was recorded in pupal and adult stage of Bombyx mori Linn. race NB₄D₂ × SH₆ at control temperature (25 ± 1°C) as well as at room temperature. The highest value of indispensable mortality (IM) 11.52 was recorded in 1^st instar larval stage of mulberry silkworm at control temperature (25 ± 1°C) and the lowest value of indispensable mortality (IM) 0.89 was recorded at 4^th instar larval stage of mulberry silkworm at control temperature (25 ± 1°C). No indispensable mortality was observed at pupal and adult stages of Bombyx mori Linn. race NB₄D₂ × SH₆ at control temperature (25 ± 1°C) as well as at room temperature. The summation of all the k-values, 0.30 was recorded at room temperature followed by 0.27 at control temperature (25 ± 1°C).