INTRODUCTORY STUDIES ON THE USE OF RADIATION IN THE CONTROL OF BLACK FLIES (DIPTERA: SIMULIIDAE)

Abstract

AbstractThese preliminary investigations of effects of radiation on black flies were undertaken to develop methods of control based on the "sterile-male" technique. Mature black fly larvae were irradiated at various exposures (from 2 kR to 32 kR) and allowed to complete development in aerated stream water in the laboratory. The larvae were preponderantly Simulium venustum Say, determined by inspection of pupae and adults. It was found that percentage pupation following irradiation remained at a fairly constant level (about 93%), whereas emergence from pupae fell from 54% at 2 kR to 0% at 28 kR. Though variable, the percentage emergence of the controls averaged 47%. Adults inspected for radiation damage appeared unchanged at the lower doses, e.g. 2 kR to 6 kR, compared with controls. At higher doses (e.g. 16 kR) the abdominal cavities usually showed a notable decrease in stored fat bodies. The anterior two-thirds of the abdomens were largely devoid of internal organs, many of which, including the ovaries and testes, were found in a degenerate condition at the posterior tip.