TY - JOUR T1 - Out of the blue: the evolution of horizontally polarized signals in <em>Haptosquilla</em> (Crustacea, Stomatopoda, Protosquillidae) JF - The Journal of Experimental Biology JO - J. Exp. Biol. SP - 3425 LP - 3431 DO - 10.1242/jeb.107581 VL - 217 IS - 19 AU - How, Martin J. AU - Porter, Megan L. AU - Radford, Andrew N. AU - Feller, Kathryn D. AU - Temple, Shelby E. AU - Caldwell, Roy L. AU - Marshall, N. Justin AU - Cronin, Thomas W. AU - Roberts, Nicholas W. Y1 - 2014/10/01 UR - http://jeb.biologists.org/content/217/19/3425.abstract N2 - The polarization of light provides information that is used by many animals for a number of different visually guided behaviours. Several marine species, such as stomatopod crustaceans and cephalopod molluscs, communicate using visual signals that contain polarized information, content that is often part of a more complex multi-dimensional visual signal. In this work, we investigate the evolution of polarized signals in species of Haptosquilla, a widespread genus of stomatopod, as well as related protosquillids. We present evidence for a pre-existing bias towards horizontally polarized signal content and demonstrate that the properties of the polarization vision system in these animals increase the signal-to-noise ratio of the signal. Combining these results with the increase in efficacy that polarization provides over intensity and hue in a shallow marine environment, we propose a joint framework for the evolution of the polarized form of these complex signals based on both efficacy-driven (proximate) and content-driven (ultimate) selection pressures. ER -