Effect of 12-hours delay and anticipation from traditional practice in silkworm mounting to spinning frames on economic traits of Bombyx mori (Lepidoptera: Bombycidae) cocoons

In this study, the aim was to determine the effect of 12 hours delay and time advancement of Bombyx mori larvae transfer to spinning frames on the economic traits of harvested cocoons. Our experience focused on the transfer of three lots of silkworm mature larvae to cocoon frames with 12 hours delay or advancement from usual spinning time. Commercial silkworm eggs were obtained and three replications of 100 larvae per each treatment were used. The larvae and cocoon conditions of hatching and rearing, feeding conditions, silkworm egg production stages were performed based on standard protocols. Rice straws were used as cocoon position (framework) in the cocoon spinning stage separately for each replication. After completion of the pupa development, total cocoon production was collected and classified based on appearance, hardness, softness, and cleanliness levels of the cortex and outer cortex into four categories, viz. good, moderate, low and double cocoons. Economic characteristics were calculated and compared between treatments using the Duncan test at p < 0.05. The comparison of economic traits of cocoons produced in perfected treatments showed no significant difference between treatments and the control. This result suggests that the 12 hours’ time anticipation or delay of larva transfer to cocoons building frames has no effect on the quantity or the quality of produced cocoons. Therefore, it is possible to shorten the rearing duration of Bombyx mori larvae by 12 hours without affecting the cocoon economic traits, and this could improve cocoon production and generate an important economic advantage in commercial sericulture.