In This Issue

Birds-of-paradise have brilliantly colored feathers that they use in ritualized dances to attract the attention of mates. The colors arise from the interference and diffraction of light caused by alternating layers of melanin rodlets and keratin. Bodo Wilts et al. (pp. 4363– 4368) found that the spectral and reflection properties of both the occipital (nape) and breast feathers of the bird-of-paradise Lawes’ parotia can be quantitatively explained by finite-difference timedomain (FDTD) modeling, a technique that allows the computation of the interaction of light with matter by directly solving Maxwell’s equations in the time domain. The authors modeled the feathers’ reflection properties using realistic feather anatomies and experimentally determined refractive index dispersion values of keratin and melanin. The authors found that the reflectance spectra calculated using FDTD were very similar to the experimentally measured reflectance spectra, confirming the structural basis for the color and showing the predictive power of FDTD modeling. The reflection characteristics of the male feathers may be tuned to the spectral sensitivities of the females’ visual system, according to the authors. FDTD modeling may have numerous applications, such as in optimized photonic crystal designs, the authors suggest. — S.R.