The Propulsion of Nonrotating Ram and Oyster Spermatozoa

The tail-wave parameters of ram and oyster spermatozoa were measured from high-speed cinemicrographs, and the observed forward velocity of the spermatozoon compared with that expected theoretically by the equation of Gray and Hancock (1955). Prediction by the theoretical equation was not good. An empirical equation was derived for ram spermatozoa which differed from the theoretical equation in that the forward velocity of the spermatozoon was independent of the wavelength of the sperm-tail, and was inversely proportional to the distal tailwave amplitude (∿ 1λ from the head). The empirical equation also applies to oyster spermatozoa which are smaller in size and simpler in structure than ram spermatozoa. Studies of the fluid movement around ram spermatozoa show that fluid is pushed ahead of the sperm and forms vortices behind the sperm. Treatment of ram spermatozoa with 0.001 M ATP leads to a significant change in the empirical equation predicting their velocity and causes a significant increase in tailwave wavelength. The drag of the distal part of the sperm-tail may result from reduced levels of ATP causing inadequate or lessened contraction. It is also possible that the drag may arise from the formation of vortices.