Fig. 4.

Analyses of Sxl ^In3/Sxl ^In3 mutants demonstrate that Sxl is essential for apyrene sperm formation. (A–F) Fluorescence microscopic images of (A, C, and E) eupyrene, (B and D) apyrene, and (F) apyrene-like sperm bundles from 4- to 5-d-old pupa with immunofluorescence staining for tubulin (green) and nuclei (magenta). (Scale bar, 100 μm.) (G–M) Semen in the bursa copulatrix and spermatheca. (G) Schematic of female reproductive organs; the dotted red line indicates the site where the incision was made. (H, J, and L) Bursa copulatrix and spermatheca from +/+ females crossed with +/+ (H) and Sxl^In3/Sxl^In3 (J) males, and those of an unmated virgin +/+ female (L). (Scale bar, 1 mm.) (I, K, and M) Magnified view of the area marked by the dotted box in H, J and L, respectively. (Scale bar, 1 mm.) (N) Fertility in double-copulation experiments; mating was performed with +/+ females. Fertility was determined as the ratio of fertilized eggs to the total number of eggs laid from a single pair or from double-copulation mating experiments (see Materials and Methods). Fertility details are shown in SI Appendix, Table S3. n, number of crosses; error bars indicate SD.