Selection for eyespot color composition affects response properties of the wing epidermis. Ectopic eyespots (arrows) were produced following damage to a non-focal position on the dorsal forewing 17 hours after pupation. Damage induces spatio-temporal patterns of gene expression in the surrounding tissue that mimic the response to diffusing focal signals  and results in an ectopic eyespot centered on the damaged site , located between the anterior (A) and posterior (P) eyespots. The color composition of ectopic eyespots was significantly different between 'GG' selected lines (A and B) and 'BB' selected lines (C and D; ANCOVA for effect of selection direction: F2,138 = 4.25, P < 0.01; Tukey's HSD: 'GG' vs. 'BB,' t138 = 6.7, Padj < 0.0001). The ectopic eyespots reveal evolutionary changes in the response properties of wing epidermal tissue after concerted selection for color composition. Earlier focal grafting and non-focal damage experiments [51, 53] demonstrate that selection for eyespot size mainly affects properties of the focal signal and the size of ectopic eyespots does not differ between lines selected for large and small eyespots [53, 95].
Allen et al. BMC Evolutionary Biology 2008 8:94 doi:10.1186/1471-2148-8-94