Jm. Greeff, HOW SERIOUS IS THE ASSUMPTION OF NO PHENOTYPIC VARIATION IN OPTIMALITY MODELS - A SEX-RATIO EXAMPLE, South African journal of science, 94(6), 1998, pp. 269-270
With the use of a sex ratio model, I illustrate when the assumption of
no phenotypic variation may lead to inaccurate predictions. Local mat
e competition sex ratio models is one case where an asymmetric fitness
function around the optimum may cause optimality predictions to be in
accurate. Despite this asymmetry, I illustrate that variation in sex r
atios must be substantial in order to lead to inaccuracies, and binomi
al variation around the optimum will not lead to any observable deviat
ions. The model allows an easy understanding of how selection on varia
tion in sex ratio decreases as the optimality point is approached.