Bombyx mori L. (Lepidoptera: Bombycidae) have been domesticated and widely used for silk production. It feeds on mulberry leaves. Mulberry leaves are mainly composed of pectin, xylan, cellulose and starch. Some of the digestive enzymes that degrade these carbohydrates might be produced by gut bacteria. Eleven isolates were obtained from the digestive tract of B. mori, including the Gram positive Bacillus circulans and Gram negative Proteus vulgaris, Klebsiella pneumoniae, Escherichia coli, Citrobacter freundii, Serratia liquefaciens, Enterobacter sp., Pseudomonas fluorescens, P. aeruginosa, Aeromonas sp., and Erwinia sp.. Three of these isolates, P. vulgaris, K. pneumoniae, C. freundii, were cellulolytic and xylanolytic, P. fluorescens and Erwinia sp., were pectinolytic and K. pneumoniae degraded starch. Aeromonas sp. was able to utilize the CMcellulose and xylan. S. liquefaciens was able to utilize three polysaccharides including CMcellulose, xylan and pectin. B. circulans was able to utilize all four polysaccharides with different efficacy. The gut of B. mori has an alkaline pH and all of the isolated bacterial strains were found to grow and degrade polysaccharides at alkaline pH. The number of cellulolytic bacteria increases with each instar.

No abstract

No abstract

No abstract

Aim: The study was conducted to elucidate the mechanism involved in adult emergence behavior of Xanthopimpla pedator a pupal parasitoid of tasar silkworm. Methodology: Behavioral observations were made to study the mechanical approaches used during emergence and SDS-PAGE analysis was carried to know the possibility of proteases in the digestive secretions. Results: The findings of the study suggest that X. pedator uses physical and chemical to achieve safe passage from the host pupae and cocoons. It was observed that during the process of emergence, X. pedator breaks host pupae by means of mandibular action (by biting the pupal shell). Further, it was noticed that to make emergence hole on host cocoon X. pedator found to employ digestive secretion to soften and disintegrate the silken shell, besides it also deploys mandibles to spread out the secretion on intended place of exit hole. SDS-PAGE analysis showed the presence of series of enzymes, possibly involved in cocoon softening. Interpretation: Findings of this study forms the basis that X. pedator, a major pupal parasitoid of tasar silkworm, uses both physical and chemical approaches to achieve safe passage from the host pupae and protective silken cocoon. Key words: Digestive secretion, Mandibular action, Parasitization, Xanthopimpla pedator