Figure 3.
Possible relative values for the sex difference in the opportunity for selection (i.e. the opportunity for sexual selection), Imates, arising from multiple mating and post-mating sexual selection, based on the sign of the covariance in mating numbers and offspring numbers for each sex; grey bars indicate the likely values of Imates due to processes other than post-mating sexual selection; black bars indicate where post-mating sexual selection is likely, i.e. where Cov♂(m,o) is positive, Cov♀(m,o) is zero, and if certain males are capable of producing abundant sperm; hatched bars indicate where post-mating sexual selection is possible, where both Cov♂(m,o) and Cov♀(m,o) are positive, females change partners with each mating and if ‘non-lottery’ sperm competition occurs.