Eyes Wide Shut: the impact of dim‐light vision on neural investment in marine teleosts |
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Authors: | Teresa L Iglesias Dan L Warren Peter C Wainwright Lars Schmitz Evan P Economo |
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Institution: | 1. Physics and Biology Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan;2. Macquarie University, Sydney, NSW, Australia;3. Senckenberg Biodiversity and Climate Research Center (SBiK‐F), Frankfurt am Main, Germany;4. University of California, Davis, CA, USA;5. W.M. Keck Science Department Claremont, Claremont McKenna, Scripps and Pitzer Colleges, Claremont, CA, USA;6. Biodiversity and Biocomplexity Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan |
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Abstract: | Understanding how organismal design evolves in response to environmental challenges is a central goal of evolutionary biology. In particular, assessing the extent to which environmental requirements drive general design features among distantly related groups is a major research question. The visual system is a critical sensory apparatus that evolves in response to changing light regimes. In vertebrates, the optic tectum is the primary visual processing centre of the brain and yet it is unclear how or whether this structure evolves while lineages adapt to changes in photic environment. On one hand, dim‐light adaptation is associated with larger eyes and enhanced light‐gathering power that could require larger information processing capacity. On the other hand, dim‐light vision may evolve to maximize light sensitivity at the cost of acuity and colour sensitivity, which could require less processing power. Here, we use X‐ray microtomography and phylogenetic comparative methods to examine the relationships between diel activity pattern, optic morphology, trophic guild and investment in the optic tectum across the largest radiation of vertebrates—teleost fishes. We find that despite driving the evolution of larger eyes, enhancement of the capacity for dim‐light vision generally is accompanied by a decrease in investment in the optic tectum. These findings underscore the importance of considering diel activity patterns in comparative studies and demonstrate how vision plays a role in brain evolution, illuminating common design principles of the vertebrate visual system. |
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Keywords: | brain evolution comparative phylogenetics diel activity patterns fish physiological evolution vision |
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