By screening Drosophila melanogaster strains harboring single P-element insertions for aberrant mating behavior, we isolated a mutant named spinster (spin^pl), in which the females had subnormal receptivity to copulation. The spin^pl females continuously display rejection behaviors typical of immature virgins such as decamping, kicking, and fending in response to courting males. Excision of P-element inserted at 52E in the spin^pl mutant resulted in phenotypic reversion to wild-type, indicating that the spin locus at 52E is responsible for altered receptivity in the mutant females.