Fig. 3

Distribution of individual values for desiccation resistance (top, circles) and pigmentation (bottom, diamonds), according to species (X axis) and population within species (shade variation among points). The y-axis values for individual cuticles on the pigmentation graph correspond to a computed greyscale value represented by the gradient bar. The thick bars indicate species means; thin bars indicate 95% confidence intervals around the mean. Desiccation resistance differs between species (F(2, 29.76); P < 0.0001) and populations within species (F(6, 4.48); P = 0.0004). Post-hoc tests indicate significant differences in all pairwise contrasts (D.nov – D. am: P < 0.0001, D.nov – D. tex: P = 0.00039; D.am – D. tex: P = 0.0023). Pigmentation differs between both species (F(2, 11.86), P < 0.0001) and populations within species (F(6, 3.13), P = 0.0083). Post-hoc contrasts indicate D. novamexicana is significantly lighter than D. a. americana (P < 0.0001) and D. a. texana (P < 0.0001); D. a. americana and D. a. texana do not differ (P = 0.96)