Submitted to: Journal of Comparative Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 27, 1995
Publication Date: N/A
Interpretive Summary: For a mating to be successful, sperm must be transferred from the male to the female. In the gypsy moth males, passage of sperm from testis to the reproductive tract follows a daily rhythmic pattern that is disrupted in continuous light. We wanted to know if the movement of the sperm is reflected in characteristic muscle contractions of the reproductive tract. In males kept in the light-dark cycles, transfer of sperm was accompanied by a characteristic pattern of contractions of a specialized portion of the reproductive tract, resulting in passage of the sperm. Such contractions were absent in males kept under constant light. Development of specific compounds that could inhibit the normal contraction of these muscles can prevent sperm transfer and result in male sterility in this important pest insect.
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 contains non-innervated muscles and is continuously motile. Patterns of 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 sperm transfer from the UVD to the SV.