Polarization sensitivity as a visual contrast enhancer in the Emperor 1 dragonfly larva,Anax imperator (Leach, 1815)

Camilla Sharkey, Julian Partridge, Nicholas Roberts

Research output: Contribution to journalArticle (Academic Journal)peer-review

15 Citations (Scopus)
337 Downloads (Pure)


Polarization sensitivity (PS) is a common feature of invertebrate visual systems. In insects, PS is well known for its use in several different visually guided behaviours, particularly navigation and habitat search. Adult dragonflies use the polarization of light to find water but a role for PS in aquatic dragonfly larvae, a stage that inhabits a very different photic environment to the adults, has not been investigated. The optomotor response of the larvae of the Emperor dragonfly, Anax imperator, was used to determine whether these larvae use PS to enhance visual contrast underwater. Two different light scattering 36 conditions were used to surround the larval animals: a naturalistic horizontally polarized light field and non naturalistic weakly polarized light field. In both cases these scattering light fields obscured moving intensity stimuli that provoke an optokinetic response in the larvae. Animals were shown to track the movement of a square-wave grating more closely when it was viewed through the horizontally polarized light field, equivalent to a similar increase in tracking ability observed in response to an 8% increase in the intensity contrast of the stimuli. Our results suggest that larval PS enhances the intensity contrast of a visual scene under partially polarized lighting conditions that occur naturally in freshwater environments.
Original languageEnglish
Pages (from-to)3399-3405
Number of pages7
JournalJournal of Experimental Biology
Issue number21
Early online date4 Nov 2015
Publication statusPublished - Nov 2015


  • polarization vision
  • Optomotor response
  • Turbidity
  • Rayleigh scattering
  • Odonata


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