Subterranean Fishes of the World

5615

2022

AIM 2022

22

Wild organisms live in complex environments, which are often stratified in terms of various chemophysical characteristics such as temperature. In such settings, animals evolve preferences to guide them to exploit optimal niches, for example living in temperature zones with minimal predators, maximal prey and/or setting optimal thermal body regulation. Ectothermic animals like fish, being directly subjected to environmental temperatures, mostly rely on their swim behavior to locate within an optimal thermal environment. However, little is known about how temperature preference evolves, or how it is controlled at the level of underlying genetic architecture. To tackle these questions, we have exploited the shift in temperature preference described in Astyanax mexicanus to investigate how this behavior has evolved between the surface and cave morphs and their hybrid offspring. We can assess individual temperature preferences in animals freely swimming along a gradient from 13°C to 37°C. The two morphs segregate for temperature preference with surface fish preferring warmer and cavefish cooler places within the gradient. The F1 descendant hybrids from surface and cavefish show a distribution within the temperature range of fish from the parental populations, localizing their swimming between 21°C and 28°C, which is also observed for their F2 offspring. We are currently using a quantitative trait loci approach to associate genetic variation with behavioral temperature choice. Understanding temperature preference on a genetic level will provide insights into the biological mechanisms controlling behavior

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