The lizard celestial compass detects linearly polarized light in the blue

Area of Science:

• Animal Behavior
• Sensory Ecology
• Neuroethology

Background:

• Ruin lizards (Podarcis sicula) possess a sky polarization compass for orientation.
• The specific spectral sensitivities for polarized light perception remain largely uncharacterized.

Purpose of the Study:

• To investigate if ruin lizards can orient using polarized light from an LCD screen.
• To determine the spectral regions essential for polarized light perception in ruin lizards' compass.

Main Methods:

• Lizards were trained and tested in a hexagonal Morris water maze under polarized light.
• Orientation performance was assessed using white, red, green, cyan, and blue polarized light with equalized photon flux.

Main Results:

• Lizards successfully oriented using white polarized light.
• Orientation was accurate under blue and cyan polarized light but impaired under red and green light.
• Blue light perception was found to be necessary and sufficient for compass function.

Conclusions:

• Perception of polarized light in the blue spectrum is critical for the ruin lizard's sky polarization compass.
• This blue light sensitivity enhances navigation reliability under challenging weather conditions like cloudy skies.