Aim: The study was conducted to find out the susceptible stage of tasar silkworm larvae to predation by stink bug and stage dependent feeding potential of stink bug over different instars of tasar silkworm. Methodology: Susceptibility of silkworms was studied by recording the daily larval mortality of all silkworm stages (1st to 5th instar) due to predation by E. furcellata. Stage specific predatory potential was estimated by recording the number of larvae required to complete each developmental stages (2-5th Nymphal instars and adult male and female). Results: Experimental results revealed that 1st and 2nd instar silkworms were most susceptible towards the attack of both nymphal and adult stages of stink bug whereas 3rd instar silkworms were moderately susceptible, however, third instar onwards susceptibility of tasar silkworm towards E. furcellata was negligible. Further stage specific cumulative predatory potential revealed that adult females of predatory bug were significantly more damaging to first instar silkworms (F= 125.20; df=5, 24; P= ≤ 0.0001) as compared to other stages by recording more larval consumption. Observations were also made on the second instar silkworms and it was observed that female adults were again superior over other stages of predatory stink bug (F= 135.30; df=5, 24; P= ≤ 0.0001). Similar trend of feeding potential was also recorded on 3rd instar silkworms; however, the rate of feeding was comparatively lesser than the first and second instar silkworms. Interpretation: Early instar silkworms were less defensive to predators attack, and were highly vulnerable to stink bug, however, as silkworm reached third instar, larvae started depending themselves by rapid head/thoracic movement to ward off the stink bugs. Significant difference in the feeding potential between different developmental stages was observed and adults being superior in feeding indicates their higher nutritional requirements as they need to be fit for reproductive performance to continue their progeny. Key words: Eocanthecona furcellata, Larval susceptibility, Predatory potential, Tasar silkworm

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