Spectral data acquisition
Dewlap reflectance was measured with an Ocean Optics USB4000 spectrometer, a pulsed Xenon light source (PX-2, Ocean Optics), and a reflectance probe encased in a black anodized aluminum sheath. The reflectance probe was set at 45ยบ to prevent specular reflection (i.e., glare; Endler, 1990). For each lizard, we collected reflectance data at three points: one in the center of the dewlap and two along the edge (Figure S2a). Dewlaps were extended using stainless-steel, reverse-action forceps. For each of the three points on the dewlap, we took three repeated measurements, resulting in nine measurements per individual. We calibrated the spectrometer after every three measurements using a Spectralon white and black standard and measured reflectance from 300 (ultraviolet, UV) to 700 nm (red) in 10-nm intervals (Cuthill et al., 1999). We included the UV spectral range since Anolis lizards have the capacity to perceive UV signals (Fleishman et al., 1993; Fleishman & Persons, 2001).