OCTOPAMINE TITER IN THE CIRCULATING FLUID OF TROPICAL TASAR SILKWORM,ANTHERAEA-MYLITTA DRURY (LEPIDOPTERA, SATURNIIDAE) AND ITS RESPONSE TO INJECTED ESTROGEN DURING CRITICAL PHASE OF DIAPAUSE TERMINATION

The presence and role of the biogenic amine, octopamine has been demon strated in Antheraea mylitta during pupal diapause. For elucidation of estrogen-induced responsiveness of insects, three consecutive injecti ons of estradiol-17-beta (E-2) at doses of 1, 5, 10 and 50 mu g/pupa o n days 130, 135, and 140 of pupal age were injected to both male and f emale pupae of A. mylitta during diapause. E-2 treatment caused a sign ificant enhancement in plasma octopamine concentration of haemolymph o n day 150 (except in males with 50 mu g dose) and reduction on day 165 in both the male and female A. mylitta. On the contrary, plasma prote in concentration was found to be higher only on day 150 when treated w ith E-2 between 1 and 50 mu g doses. Octopamine titer in haemolymph pl asma always remained higher in male than its female counterpart while in case of plasma protein titer it was found to be just reverse in con trol animals. E-2, @ 1-50 mu g/pupa caused a significant reduction in pupal duration inducing early moth eclosion. Egg production increased at lower doses and decreased at higher doses of this hormone. E-2 at t he dose by 0.5 mu g/pupa remained ineffective in all the cases except in elevating the female plasma protein titer and egg production. Hence , diapausing pupae of tropical tasar silkworm, A. mylitta is physiolog ically responsive to vertebrate estrogen, E-2.