Age specific life table of mulberry silkworm, Bombyx mori’Linn. race NB4D2 x SH6 at two different temperatures ranges under laboratory conditions

Abstract

The study on age specific life table of Bombyx mori Linn. race NB4D2 x SH6 reared on leaves of mulberry (Morus alba) plant variety S-1 at two different temperatures viz. control temperature (25 ± 1 °C) with 75 ± 5% relative humidity and room temperature in the laboratory of Sericulture Research, Demonstration and Training Unit, Department of Entomology, College of Agriculture, Sardar Vallabhbhai Patel University of Agriculture & Technology, Meerut-250110 (Uttar Pradesh), India. Data revealed that Bombyx mori Linn. race NB4D2 x SH6 required 37 and 40 days to complete its life cycle at control temperature (25 ± 1 °C) with 75 ± 5% relative humidity and room temperature, respectively. At control temperature, the highest mortality 85.19 per cent was exhibited at 36th day followed by 49.06 per cent at 35th day and the lowest mortality 1.12 per cent was recorded on 5th day followed by 1.14 per cent on 6th day. In case of room temperature, the highest mortality 88.89 per cent was recorded at 39th day followed by 66.67 per cent at 38th day and lowest mortality 1.20 per cent was recorded at 8th day followed by 1.35 per cent at 15th day. There an initial drop in survivorship (lx) was seen followed by an intermittent steady decline with 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) with 75 ± 5% relative humidity as well as at room temperature till the end of generation.