Ste1 is dominant; Ste1/Dp(1;f)LJ9 XO males have star-shaped crystals in their spermatocytes while Ste+/Dp(1;f)LJ9 XO males have needle-shaped crystals in their spermatocytes. Male Ste1 flies also carrying Ts(1Lt;YSt)E1, Ts(1Lt;YSt)N29, Ts(YLt;4Lt)PFB15 or Ts(1Rt;YLt)E15 have scarce needle-shaped crystals in their spermatocytes. Male Ste1 flies also carrying Ts(YSt;4Rt)PFB15, Ts(1Lt;YSt)E15, Ts(1Rt;YLt)P7+Ts(YSt;4Rt)PFB15, Ts(1Lt;YSt)E15+Ts(1Rt;YLt)P7, Ts(1Rt;YLt)P7 or Ts(1Lt;YSt)E15+Ts(YLt;3Lt)W27 have abundant star-shaped crystals in their spermatocytes. Male Ste1 flies also carrying Ts(1Lt;YSt)E1+Ts(YLt;3Lt)W27 or Ts(1Lt;YSt)E1+Ts(1Rt;YLt)P7 have scarce needle or star-shaped crystals in their spermatocytes. Male Ste1 flies also carrying Ts(1Rt;YLt)E1 have scarce star-shaped crystals in their spermatocytes. Male Ste1 flies also carrying Ts(1Rt;YLt)N29 have abundant needle or star-shaped crystals in their spermatocytes. Male Ste1 flies also carrying Ts(1Rt;YLt)P7+Ts(YSt;4Rt)PFB15 or Ts(1Lt;YSt)E15+Ts(1Rt;YLt)P7 are sterile.