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 multidimensional 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.
Bibliographical noteFunding Information:
Biotechnology and Biological Sciences Research Council (BB/G022917/1 and BB/H01635X/1 to N.W.R.), and the Air Force Office of Scientific Research (FA8655-12-1-2112 to T.W.C., N.J.M. and N.W.R.) supported this work. S.E.T was a recipient of a Yulgilbar Foundation Lizard Island Postdoctoral Fellowship.
- Mantis shrimp
- Multi-modal signal
- Polarization vision
- Sensory bias
- Signal evolution