Fig 1.
Effects of experimental elevation of testosterone.
Change in mean circulating testosterone (T) concentrations in female C. decresii pre- implant, 1 week post-implant, and 4 weeks post-implant.
Fig 2.
Effect of testosterone on female throat colour expression for each morph.
Pre-testosterone implantation (left) versus same lizard at peak of morph expression (right): A) orange, B) yellow, C) orange+yellow, D) grey.
Fig 3.
Discriminant function analysis (DFA) confirming the presence of four discrete throat colour morphs following testosterone implantation.
Orange: red squares; orange+yellow: orange triangles; yellow: yellow triangles; and grey: grey diamonds. Individuals are plotted for canonical variables A) 1 and 2; B) 1 and 3; and C) 2 and 3, with 95% confidence ellipses.
Fig 4.
Mean percent of A) red, B) yellow and C) grey components of throat colouration over time.
Data for each morph category were derived from digital images using segmentation analysis (n = 40). Significant effect of time for proportion red in O and OY morph, and proportion grey in OY morph (quadratic trendline fitted); p < 0.0001 in each case.
Table 1.
Effect of testosterone implantation on components of female colour expression.
The change in proportion of throat colours (red, yellow and grey) was derived from segmentation analysis of digital images, and the chromatic (colour) and achromatic (luminance) contrast of the primary throat and bib was derived from spectral measurements. For significant quadratic interactions between morph and time (denoted by *), each morph was analysed separately (Table 2). Values remaining significant after applying FDR corrections in bold.
Table 2.
Linear and quadratic changes in colour over time for each morph separately.
Only colour variables for which there was a significant interaction between colour morph and time are presented. Values remaining significant after applying FDR corrections in bold.
Fig 5.
A) Chromatic (CC; colour) and B) achromatic (AC; luminance) contrast of primary female throat colouration against a neutral background (30% grey), for each colour morph. CC and AC measured in units of just noticeable differences (JND).