DAILY RHYTHM IN MYOGENIC CONTRACTIONS OF VAS-DEFERENS ASSOCIATED WITHSPERM 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 s perm bundles into the seminal vesicles (SV) occurs in a daily rhythm. The UVD undergoes different types of contractions despite the fact tha t its musculature appears to receive no innervation. Patterns of the U VD movements were recorded throughout the daily sperm release and tran sfer 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 constan t light, which fail to transfer sperm, this contraction pattern was ab sent. It is concluded that the vas deferens muscles undergo daily chan ges in contraction pattern in phase with the light-dark cycle. The inc reased muscular contractions appear to be a causal factor in the gated sperm transfer from the UVD to the SV.