English: Calcium-insensitive GFP fluorescence is not altered by oocyte passage. A representative wildtype spermathecal transit imaged using xbIs1101[fln-1p::GCaMP]. Oocyte entry occurs from the right at 30 seconds. The sp-ut valve is constricted until it begins to dilate at 6 minutes and 30 seconds, and exit is complete by 10 minutes. More compact (denser) regions of the spermatheca appear brighter; however, there is no change in the overall average fluorescence intensity due to shape changes. The sujc core cell is visible below the embryo. The movie is shown twenty times faster than real-time with a lookup table to visualize low intensities (cool colors represent low intensity). Time is shown as minutes:seconds and begins 30 seconds before oocyte entry. The entire region shown (100 µm×50 µm) was used for the mean fluorescence intensity measurements in Figure 4C.