Experimental Studies on Pole Cells and Midgut Differentiation in Diptera

Abstract

Highly localized irradiation with ultraviolet of the posterior polar region of eggs of Drosophila melanogaster and Lucilia cuprina in pre.pole cell and pole cell stages results in reduction in numbers of the cuprophilic cells of the middle midgut as well as in reduction of gonad size and number. Carefully timed eggs were exposed to dosages of ultraviolet (from a source giving about 90 per cent. at wavelength 2536 A) ranging from 1200 to 2400 I-' W sec/cm2 over periods of 2-4 min. Treatments at the time of active pole cell formation were found to be most effective in producing defects of both gut and gonads, thus demon· strating the common origin of the cuprophilic cells of the middle midgut and the germ cells of the gonads.