Impact of High Dose of Gamma Radiation on Field Collected <i>Aedes aegypti</i>

Abstract

Mosquitoes that transmit pathogens to humans received much attention during last few decades. Aedes aegypti causes certain diseases like dengue, yellow fever andchikungunya. There are no effective vaccines and drugs available for those diseases. The control of Aedes aegypti is the only effective way for prophylyxis from this disease. Radiation has played an important role in insect pest management. To determine the radio sensitivity, an experiment was conducted to understand the effect of γ - radiation at higher doses on immature stages of Aedes aegypti. One day old pupae were irradiated with variable doses between 100Gy to 1000Gy to study the pupal viability, adult emergence and development of malformation if any. The dose response curve between the pupal viability and dose was determined and there was a marked difference in radiation sensitivity . It was observed that the pupal viability decreased with increase in radiation dose in dose dependent manner. Pupal viability of about 99.2%, 61.4%, 42.5%, 13.4%, 7.5%, 6.7% and 3.9% was found after exposure to gamma radiation at 100Gy, 250Gy, 400Gy, 550Gy, 700Gy, 850Gy and 1000Gy respectively. Similarly, adult emergence was also drastically affected by radiation exposure. The percent adult emergence from irradiated pupae were about 99.2%, 61.3%, 42.4%, 13.4%, 7.2%, 6.4%, and 3.0% at 100Gy, 250Gy, 400Gy, 550Gy, 700Gy, 850Gy and 1000Gy respectively. Morphological deformities on both pupae and adult of Aedes aegypti were noticed after irradiation indicates the somatic damage of pupae and adults. It was observed that head, thorax and part of the abdomen with fore wings were released but the rest of the body still attached to the puparia. Similarly, few malformed adults with curled legs, crumpled wings and with curved abdomen were obtained due to the effects of high dose of gamma radiation at 400Gy and above.