Fig. 2.

Effect of short and long anther exsertion on mean number of visits to plants by bees and flies. Data are residuals after controlling for petal area and number of open flowers per plant. In 2002, butterflies were not included because of the low number of visits (see Table 2). P-values for the significance of the difference from zero of the regression slopes are denoted for each visitor type in the key. (A and B) Effects of short and long stamen exsertion in the 2001 exsertion selection experiment. (C and D) Effects of short and long stamen exsertion in the 2002 dimorphism selection experiment.