Improvement of Rearing Performance in Muga Silkworm Antheraea Assamensis with Hormone Treatment

Reproductive efficiency of economic insects and its rearing performances are greatly affected by hormonal activities together with the environmental and cultural practices. Two different hormones were selected for tropical application on muga silkworm (Antheraea assamensis Helfer) to study their effect on the overall rearing performances. JH-III (Juvenile hormone) in three different concentrations and 20-Hydroxyecdysone i.e. 5, 10 and 15 μg/g body weight (w/w) were applied exogenously on head region of 5th instars 1st day larvae of muga silkworm. Larvae treated with higher concentration of 20hydroxyecdysone (15 μg) and JH-III (10 μg) were significantly superior in terms of cocoon formation (86.2±3% and 78.4±2.97%), cocoon weight (6.174±0.34gm and 5.616±0.07gm), pupal weight (5.888±0.10gm and 5.078±0.04gm), shell weight (0.576±0.005gm and 0.532±0.01gm) compared to that of control. Similarly, the length of ovary (10.26±0.22 cm and 9.38±0.12cm) and fecundity (179.3±8.35 nos and 163.6±2.97 nos) in the treated larvae was also higher. Application of JH-III has resulted in the prolongation of larval period (8.0±0.44days) however, treatment with 20-hydroxyecdysone has shortened the larval period (5.8±0.37days) with higher silk ratio (8.346 ±0.29 %). Thus, JH-III and 20hydroxyecdysone can successfully be applied for ovarian development which in turn can exhibit reproductive efficiency of muga silkworm.