Fig. 1. Schematic representation of the rhythm of sperm release in moths. Sperm bundles (SB) descend from the testis (T) into the upper vas deferens (UVD) during a period of a few hours before and after lights-off. Sperm bundles are retained in the UVD lumen during the night and then transferred to seminal vesicles (SV) within a few hours after lights-on. During each daily cycle, the sperm bundles closest to the base of the testis are released in this stepwise fashion. Black and white bars represent, respectively, the dark and light phases of the 16 h:8 h L:D cycle.
