Daily rhythm in myogenic contractions of vas deferens associated with sperm release cycle in a moth

In the gypsy moth, Lymantria dispar, release of sperm bundles from the testis into the upper vas deferens (UVD) and subsequent transfer of sperm bundles into the seminal vesicles (SV) occurs in a daily rhythm. The UVD undergoes different types of contractions despite the fact that its musculature appears to receive no innervation. Patterns of the UVD movements were recorded throughout the daily sperm release and transfer cycle. In males kept in light-dark cycles, transfer of sperm from the UVD to the SV was accompanied by a characteristic pattern of UVD contractions of high frequency and amplitude. In males kept in constant light, which fail to transfer sperm, this contraction pattern was absent. It is concluded that the vas deferens muscles undergo daily changes in contraction pattern in phase with the light-dark cycle. The increased muscular contractions appear to be a causal factor in the gated sperm transfer from the UVD to the SV.Abbreviations LD light-dark - LL constant light - SV seminal vesicle - UVD upper vas deferens