EFFECT OF DIFFERENT FOOD LEAVES ON REARING PERFORMANCE IN INDIAN TROPICAL TASAR SILKWORM, ANTHERAEA MYLITTA DRURY (LEPIDOPTERA : SATURNIIDAE)

An attempt was made to rear the ecorace Daba (Bivoltine, domesticated) of tropical tasar silkworm (Ant heraea mylitta D) on leaves of Terminalia éomentosa W&A, Lagerstroemia parvijiora Roxb. and in their combinations to evaluate the food associated traits. The larval span (days), spinning period (h) were lowest if the caterpillars were fed on T. tomentosa. The effective rate of rearing per cent, cocoon yield/dfl, Single Cocoon Weight (g),, Single Shell Weight (g) and absolute silk yield (g) remained significantly higher on T tomentosa over L. parvijiora and its combinations with T tomentosa. The productivity of cocoons from a single disease free laying remained 36.60 cocoons on L. parvij7ora. However, there was no difference in the yield/dfl if the caterpillars are reared on F2 (L. parvijiora) and F3 (rearing on T tomentosa upto 3d stage and subsequent rearing on L. parviflora from 4th to 5thj stage). The yield on L. parviflora can be increased if this food plant is used in the middle of fifth instar of larvae after live days of fifth instar feeding on T tomentosa (F5), with 45.2 cocoons and 52.800 grams of absolute silk from a single disease free laying.The relation between independent associate cocoon weight (g) with dependent associate shell weight (g) was significant (P<O.05, df 13) in all the food combinations except F3 i.e. rearing on T. tomentosa up to stage and subsequent rearing on L. parvijiora from 4tb to 5th stages (P>0.05 df: 13). Food ¡n combinations of F2 and F4 presented positive association of the shells with their cocoons. However, there was a negative intercept in F2 and F4 in the regression function. Thus, the association of a combination of feed empowered the silk insect larvae to acquire the tolerance against stress associated with absence of food of prime choice with better cocoon and shell association due to relative presence of certain free amino acids in the fourth and fifth instar larvae reared on ¡nterchange of food plants. Thus, L. parvijiora can be utilized for tasar silkworm rearing in the fifth instar where the food of prime choice T tomentosa is in scarce and L. parvijiora ¡s in abundance in the vicinity of farmer’s hamlet.