Variation of Soutellar Bristles in Drosophila

Abstract

Three strains (70, 71, and 73) of D. melanogaster, wild type for the scute locus, were exposed to temperatures of 16, 20, 25, and 30°0 during larval development. They were found to vary in their temperature response; strain 70 showed a maximum development of additional bristles at the anterior site at l6°C, additional bristles were most frequent at the interstitial site between 20 and 25°0, and extra bristles at the posterior site rose to a maximum at 30°0; in strain 71 only tho maximum for the anterior site at 16°C was observed; strain 73 had very few additional bristles at any site over the entire temperature range. Modification of the size of the flies by growing them under crowded conditions or by enriching the modium had no effect on the pattern of the temperature response.