Graphical interpretation of the quantity-quality trade-off. Decrease in egg number with egg mass for andromorphs (black symbols, solid line) and gynomorphs (white symbols, dashed line). Mean (± 1SE) values of both fecundity traits are given for each study population and for both investigated years. Circles and triangles represent, respectively, fecundity in the first and the subsequent year. Regression curves are based on the parameter estimates of the ANCOVA model, thus including geographical and temporal dependency of the data points.