Changes to the estimated value of [[beta].sub.0] also affect estimates of the fertilization rate constant, [beta], in the VCCW model, as well as the value of the ratio between the two rate constants ([beta]/[[beta].sub.0]).
Although the ability of the VCCW model to predict fertilization has been comprehensively tested in the laboratory by varying sperm age, sperm concentration, egg concentration, and sperm-egg contact time (Vogel et al., 1982; Levitan et al., 1991), the ability of the model to predict the quantity underlying fertilization--collisions between sperm and eggs--Has never been tested.
I predicted collisions of sperm to eggs using the portion of the VCCW model designed for this purpose (Eq.
However, the empirical collision rate is significantly lower than that predicted by the VCCW model [AN-COVA; [r.sup.2] = 0.859; P(interaction term) < 0.0001].
By accounting for dead sperm, I reduced the disparity between the slope predicted by the model and the slope of empirical data, but the empirically estimated collision rate was still significantly lower than the VCCW model predicted [ANCOVA; [r.sup.2] = 0.859; P(intera ction term) < 0.0001].