Expansion and contraction of epithelial chromatophores in response to diet and background substrate. Epithelial tissue from prawns fed different levels of dietary astaxanthin (0, 25,
50 and 100 mg/kg) for 6-weeks (T0), and then exposed for 2 h to black (T120 Black) or white (T120 White) substrates. Images show the dorsal surface of the first abdominal segment from each prawn, and the inset a magnified view from the same region of each segment.