Female responses to two-monitor video playback tests. Female responses to two-monitor video playback tests. The brightness of the vocal sac of the male on each monitor was varied. For each pair of stimuli tested, graphs show the percentage of females that chose each monitor and their response latency. Drawings flanking the graphs illustrate the particular combination of vocal sac brightnesses tested; data points on the left side of graphs correspond to the stimulus depicted on the left, those on the right side correspond to the stimulus depicted on the right (W, white; LG, light gray; MG, medium gray; DG, dark gray; B, black). Asterisks indicate female responses that were significantly different between the stimuli (ANOVA; LG versus MG, P=0.047; all other cases P≥0.12). Michael S. Reichert et al. J Exp Biol 2014;217:3254-3262 © 2014. Published by The Company of Biologists Ltd