Figure 4

Frequency of cone pigments and spectral reflectance of the color pattern of cichlids. (a) Frequency of cone pigments in M. zebra, M. auratus and P. taeniolatus. Visual pigments: SWS1 (black), SWS2b (violet), SWS2a (blue), RH2b (green), RH2a (orange) and LWS (red). Cone pigment frequency varied across species, with LWS and SWS1 showing the largest frequency variation between species. The frequency of SWS1, SWS2a and LWS differed significantly across species (Fisher's exact test, P = 0.0005, P = 0.002 and P = 0.00001, respectively). The frequency of SWS2b, RH2a and RH2b did not differ significantly across species (Fisher's exact test, P = 0.05, P = 0.09 and P = 1, respectively). Error rate was set to α = 0.0083 following Bonferroni correction for six hypothesis tests. (b) Average normalized spectral reflectance (n = 10; black lines) of the color pattern of M. zebra (solid line), M. auratus (dashed line) and P. taeniolatus (dotted line). The normalized absorption of LWS visual pigment (red line) and the normalized sidewelling irradiance measured at 5-m depth in Lake Malawi (blue thin line) are also depicted.