CAREER: The multidimensional role of behavior in evolution

Natural selection can be a powerful agent of adaptation in species. Yet, organisms are not exclusively at the environment’s whim and mercy. Through their behavior, organisms can dictate their environmental conditions and guide the selective pressures they experience.

Consider, for example, a lizard darting into the shade, a mouse digging a burrow, and humans building houses and engineering indoor heating or cooling. This project will test the idea that behavior can shield organisms from natural selection, modify adaptive response, and enhance the exchange of genetic material. The project will focus on anole lizards, a system that provides the variation and replication necessary to isolate the role of behavior in adaptation.

The results of this study will provide a new lens on natural selection by illustrating the role that organisms exert over their own adaptive trajectories; all animals - including humans - can use behavior to negotiate their environments. This project contributes to a better prepared STEM workforce through student training. Educational modules will be developed for the undergraduate classroom, providing experiential learning in experimentation, bioinformatics, and statistics.

The results from this project will be infused into a museum exhibit in the Yale Peabody Museum, which is free to all visitors and is the most visited landmark by Connecticut schoolchildren. Local educators and scientists will work together in summer workshops to develop educational modules for the museum exhibit that align with state curricula, providing experiential learning opportunities for K-12 students.

Natural selection is a powerful agent of evolution; shifts in temperature across environmental gradients, for example, should favor local adaptation and limit gene flow among populations. Yet, homeostatic behaviors like behavioral thermoregulation (e.g., basking) may buffer organisms from selection, and potentially create corridors for gene flow across environmental gradients.

This project will investigate the genetic signatures of thermoregulatory behavior, and test whether homeostatic behaviors circumvent climatic obstacles to dispersal and enhance gene flow across environmental gradients. To do so, this project will leverage the replicated behavioral, physiological, and ecological diversity of anole lizards as an ideal study system.

Thermal modification behavior will be quantified through detailed field studies, with preliminary results indicating that lizard species from canopied forests are poor thermoregulators while those from forest edges thermoregulate effectively. The connection between thermal behavior and the phenotype will be quantified by laboratory-based investigation of thermal and hydric physiology, and functional morphology.

Preliminary results indicate that thermoregulating lizards exhibit physiological stasis across elevation, while thermoconformers exhibit the expected clinal pattern of local adaptation. Lastly, 3RAD sequencing will be used to infer patterns of gene flow across elevation, and those patterns will be compared among thermoregulators and thermoconformers.

Preliminary results indicate that thermoregulating lizards exhibit high rates of gene flow across elevation, suggesting that buffering behaviors shield these animals from selection and facilitate gene connectivity among populations from environmentally dissimilar habitats. The results of this study will provide a new lens on natural selection by illustrating the role that organisms exert over their own evolutionary trajectories.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.