Comparative studies of ecdysone in outdoor and indoor reared tasar silkworm, Antheraea mylitta Drury
G Shiva Kumar, G Shamitha
The Indian tropical forest-grown, Tasar silkworm, Antheraea mylitta Drury Daba TV (Tri-voltine) ecorace has been facing problems during outdoor rearing, heavy mortality of larvae due to predators, parasites; irregular hatching of eggs leading to prolonged larval period, climatic hazards; indefinite period of diapause leading to erratic moth emergence followed by inadequate seed support and other grainage (egg production) problems. In order to overcome these problems indoor rearing concept has been evolved. In the present investigation, a comparative analysis of ecdysone in outdoor and indoor reared fifth instar, 10th day larvae of tasar silkworm has been taken up as they control moulting period. In spite of feeding same quality of leaves for both rearing methods of outdoor and indoor reduced larval period observed in Vth instar stage of indoor rearing. As early pupation in the fifth instar larvae of indoor rearing is mainly owing to a rise in the hormone concentration, the present study based on quantification of ecdysone hormone level in the haemolymph of tasar silkworm of outdoor and indoor on fifth instar 10th day was taken up. Ecdysone levels of fifth instar larvae in the first and third crops of indoor rearing found to be increased by 15% when compared to those of outdoor reared ones.