Assembling the building blocks of advanced color and polarization vision

The natural lightscape is awash in a wealth of visual information that animal eyes have evolved to interpret and exploit. Often, they possess visual capabilities beyond our own, including perception of additional colors (wavelengths) or the polarization of light (the orientation of light waves - an entirely separate visual modality we have no sensitivity to). However, little is known about how these advanced visual systems evolved. I hypothesize that they emerged from segregated information channels tuned to distinct stimuli in certain regions of the light environment that control specific behaviors. My proposal aims to explore how new color and polarization circuits formed and integrated while maintaining their crucial primary functions. I will approach this from multiple, converging perspectives using invertebrate models with uniquely informative visual specialization: 1) water fleas, with miniaturized compound eyes featuring high degrees of regional specialization for color and polarization sensitivity, possibly akin to early visual systems; 2) mantis shrimp with the most elaborate color and polarization photoreceptive arsenal in nature; and 3) firefly squid, potentially the only cephalopod mollusk that has convergently evolved color vision in addition to their acute polarization sensitivity. From each of these perspectives, I will use advanced techniques to explore the building blocks of their color and polarization vision (photoreceptors), how they are assembled to collect and interpret visual information (neural circuitry), and how they function (visual ecology). I will discover the environmental factors that drive extreme color and polarization vision in animals, unravel the interplay between these modalities, and reveal the principles that ensure these advanced circuits are fast, efficient and accurate. Beyond delivering new understanding of sensory evolution, this work will have broad impacts for bioinspired sensing and environmental light monitoring.