Meeting Abstract
The “eyeless” or “ blind” cave fish Astyanax mexicanus is a species of teleost adapted to the low-light conditions of their native cave environments in Mexico. One sensory adaptation of these fish is an extensive and well-defined lateral line system, thought to enhance sensitivity to water-borne mechanical stimuli. In early ontogeny, cave fish do possess rudimentary eyes, but over the course of development, eye degeneration occurs in parallel with maturation of the lateral line mechanosensory organs. This study explores the developmental intersection of these two different adaptive sensory programs. My goal was to correlate the developmental loss of visual status by looking to identify critical points in time where the logistic degeneration of cave tetra eyes and advancing logistic growth of neuromasts correlate with one another over developmental time. To correlate eye degeneration versus mechanosensory capacity in post-hatch cave fish, DASPI-labeled superficial lateral line neuromasts at discrete opercular and orbital locations were imaged using fluorescent microscopy. Neuromast densities were then compared to measures of eye size in the same fish. Logistic analysis of results showed that cave tetras express inverse exponential rates of eye degeneration and neuromast formation as fish became larger in length. Neuromasts appeared to be in initial stages of reaching maximum densities in the size classes of fish used in this study, suggesting that when eye degeneration was complete, neuromast densities cease advancement in response. It is thought that this pattern could be due to biological processes such as genetic pleiotropy. Quadratic polynomial analysis also suggests that orbital neuromasts develop earlier in developmental time than operculum neuromasts, suggesting that separate developmental processes may code each neuromast collection.
