Raw Throat Relfectance Measures

Raw values of throat reflectance measures of all fish used. Data are separated into 2010 and 2011 year categories, for both male and female fish. Male ID (numbers) correspond to that year's trials, and not to male ID in the combined data set. For the combined data set, males are numbered 1-63, starting with the first male in 2010 and continuing sequentially through the end of the 2011 year. Con-specific or intruder males used in the con-specific male sequential choice trials are indicated with an 'I' (for example M7-I is the con-specific male presented to subject male 7

Intruder male throat color affects subject male behavioral response.

<p>Regression analysis of conspecific male trials shows that males display a significant, negative response to intruder male throat color (R² = 0.188, df = 29, P = 0.016).</p

Variation in female throat color.

<p>Variation in stream resident female throat coloration alongside a typical male.</p

Population-level male mate preferences.

<p>Model coefficients and significance (P) for the fixed effects on male responsiveness (PC1) of three female traits, trial number, and the categorical variable representing year of the trial (2010 vs. 2011). Fixed effects of the female traits would be indicative of population-level male mate preferences for them, and hence directional sexual selection on them.</p><p>Population-level male mate preferences.</p

Predicted male mating response for female traits.

<p>Fitted mate preference function for each of the 63 males from the sequential choice mating trial assay, as estimated from a random coefficient mixed model (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0120723#sec002" target="_blank">Methods</a> for details). Predicted values of the male mating response (PC1) are plotted against the composite trait values obtained by scoring females for the linear combination of the three traits (female throat color, spine color, standard length) described by the first eigenfunction of the random effect covariance function of male preference ([−0.210, −0.169, 0.005] for the three traits respectively).</p

Male response differs between female and male presentations.

<p>Paired <i>t</i>-test revealed that in sequential choice trials, males (A) zigzagged significantly more toward females than males, but showed no difference in the number of (B) bites. Error bars represent ±1 S.E</p

Average throat reflectance values of females used in simultaneous choice trials.

<p>A comparison of the average throat reflectance values of ‘dull’ versus ‘red’ categorized females used in simultaneous choice trials. Reflectance values were assessed in a tetrahedral color space model to obtain a single value for female throat color, a measure of chroma. Females were then assigned to a ‘red’ or ‘dull’ throat color category using this value, the highest value from each pair receiving the ‘red’ classification. Average subject male throat reflectance values included for comparison. Error bars represent ±1 S.E.</p