Developmental parameters and cocoon production by five silkworm, Bombyx mori L. (Lepidoptera: Bombicidae) hybrids at different feeding regimes

Abstract

The developmental characteristics of five silkworm hybrids -­‐ J₂J₁, K₁W₁, W₁D₂, J₁C₁, and C₁J₂ – fed with mulberry leaves, 2, 3, 4 and 5 times per day were investigated in a 5x5 factorial arrangement fitted into a completely randomized design (CRD) with four replicates. The aim of the experiment was to identify the best of the four feeding regimes for cocoon production optimization. Each replicate consisted of one hundred silkworm larvae of each hybrid. Results showed that larval and pupal weights and fecundity were significantly jointly influenced by silkworm hybrid and feeding regime. Hybrid C₁J₂, when fed 3 times daily, produced the highest larval and pupal weights, and fecundity relative to other hybrids and feeding regimes, while higher fecundity was obtained at 4 and 5 feedings per day. Whereas larval developmental period was significantly influenced by silkworm hybrids, adult longevity was influenced by feeding regime. Mortality was higher with C₁J₂ at 1 feeding per day compared to other times of feeding, whereas adult longevity was influenced by feeding regimes. Shell weight and shell ratio were influenced jointly by silkworm hybrids and feeding regime. At feeding regime 1, significantly lower number and weight of cocoons were produced. Highest cocoon and shell weights were obtained from C₁J₂ at feeding regime 4 compared to other hybrids and feeding regimes.