Figure 1

Mating induces opening of the oviduct lumen. (A-C) Unmated; (D-F) Mated; (A and D) Entire reproductive tract was embedded in plastic; ovary (OV), lateral oviducts (LO), common oviduct (CO), seminal receptacle (SR), spermatheca (SP), uterus (UT) are labeled. Scalebar is 200 μm. (C and F) Illustrations that highlight the lumenal space (yellow) are shown. (B and E) Toluidine blue stained 1-μm thick section of region marked by box in A and D, respectively. (A) Common oviduct appears constricted (arrow). (B and C) Lumen is visible in lateral oviducts, but is barely detectable in constricted region of oviduct (arrow). In the lower common oviduct, darkly stained material is observed in the lumen (inset; bar is 10 μm). (D) Egg fills one of the lateral oviducts. Common oviduct does not appear constricted (boxed region). (E and F) Oviduct lumen is more visible in mated females (arrows). Dark staining material is not detected in lumen.