Meeting Abstract
Sensory systems evolve under the influence of other senses, as well as the external environment. Because sensory systems can be physiologically expensive to produce, use and maintain, selection for the elaboration of one sensory system may be coupled to the degradation of another. However, because ecological factors may have selected for the benefits of multimodal perception, different sensory systems may be expected to be correlated in their evolution. This study aims to determine how sensory systems evolve with each other under different ecological pressures. Morphological metrics of the visual, olfactory, and lateral line systems of marine, as well as lacustrine benthic and pelagic populations of threespine sticklebacks were obtained and used to analyze the relationships between sensory systems and the environment. We hypothesized that: 1) sensory characters of freshwater fish would be distinct from that of marine fish, which are characteristic of the ancestral stickleback condition; and further 2) pelagic fish would show elaboration of visual senses and reduction of non-visual senses, relative to the ancestral condition, to maximize use of the light-rich environment. Benthics were predicted to show the opposite trend, to compensate for the reduced availability of visual information. Initial data indicate a positive correlation of the visual and mechanosensory systems in all habitats, and benthics evolving enhanced visual and mechanosensory systems relative to other habitats. No significant differences in the chemosensory system have been found. This suggests that while divergence of some sensory systems has occurred due in part to variation in the environment, rather than trade-off visual and non-visual senses, the correlated evolution of visual and mechanosensory systems occurs independently of the olfactory system.
