Fig. 6. Effects of bafilomycin (BA) on the pH in the lumen of the upper vas deferens (UVD). UVDs were injected at Zeitgeber time 8 (Zt8) with bafilomycin or 6 % dimethylsulfoxide (Solv.) or left untreated (Intact). The pH was measured at Zt8 in groups of control moths and at Zt16 in injected moths. Bafilomycin prevented the decline in pH relative to the beginning of the experiment at Zt8, while solvent-injected and intact UVDs showed a statistically significant (Student’s t-test; P<0.01) decline in pH. Each column represents the pH (mean ± S.E.M.) for eight individuals per treatment.