Effects of SR [sex ratio]-spirochete infection on Drosophila melanogaster carrying intersex genes

Three sex-transforming genes (ix, tra-D, and dsx) in D. melanogaster were examined with respect to possible interactions with the NSR strain SR-spirochetes. The SR-spirochetes exerted a lethal effect on XY but not on XX individuals, regardless of whether they were phenotypically males, intersexes, or females. These results, taken together with those reported by Sakaguchi and Poulson (1963)on tra and 2X3A intersexes, both of which are resistant to the androcidal action of SR-spirochetes, support the interpretation that male susceptibility is a consequence of the single X condition.