Any variation in the mating process that includes the male stopping at the vulva (usually after backing) compared to control. In C. elegans general vulva location (stopping) requires the hook sensillum.
Any variation in the male's ability to locate his partner's vulva when backing along the ventral side of the partner during mating compared to control. In C. elegans the male stops at the vulva, coordinates his movements to the hermaphrodite's, and positions his tail precisely over the vulva so that he may insert his spicules and ejaculate.
