Research

Inferring the impacts of closely-related species on phenotypic evolution

(with Julio A. Rivera, J. Jaime Zúñiga-Vega, and A. Michelle Lawing; NSF DEB 2154897)

 In a classic example of natural selection on islands, the remarkable differences among the bills of Darwin’s finches allow these species to co-exist without competition because they eat very different types of food. The same processes may also be important in shaping evolution in many other organisms, but their effects can be difficult to detect without the clear geographic boundaries of islands and the strikingly different body forms of Darwin’s finches. This project focuses on Sceloporus lizards, a large group of species that often co-exist, and that are abundant throughout Mexico and the southwestern United States. The researchers gather detailed measures of body shape and preferred environments, and develop new statistical approaches to identify distinct body and habitat types from generalist, mainland species. They then test whether species that co-exist in the same geographic areas differ from each other in body form and ecology, and reconstruct the ancient history of co-existing species with geographic precision, using public data readily available on the internet. The project emphasizes international collaboration (US and Mexico) and community science, embedding the research in formal courses taught at three institutions, and sharing the results through museum exhibits as well as with other scientists.

Closely related taxa that live in geographic proximity (i.e., sympatric congeners) impose a potentially widespread and under-recognized evolutionary force. This project gathers new data from CT scans and geometric morphometric analyses of museum specimens, conducts lizard field surveys of 500 sites in Mexico and the southwestern United States, and develops new phylogeographic tests of whether Sceloporus lizards tend to co-exist with closely related taxa that differ from themselves. In addition, researchers combine phylogenetic, climate, and fossil information to reconstruct the detailed evolutionary and geographic history of Sceloporus species assemblages and their morphologies, testing hypotheses about the processes by which interspecies interactions lead to species turnover and diversification.  These analyses will test hypotheses about the importance of foraging, habitat use, and parity as drivers of interspecific interactions, ask whether sympatric congeners have imposed similar selective pressures in repeated evolutionary episodes, and test for links between the biodiversity of sympatric species assemblages (e.g., species richness, phylogenetic diversity) and landscape characteristics (e.g., habitat heterogeneity). By addressing these questions with public data, readily accessible via the internet, the project also contributes to future studies by adding new data and R scripts for those who want to conduct similar analyses with other taxa.

Sensory systems & climate change

(with Piyumika Suriyampola, Monserrat Suarez-Rodriguez, Delawrence Sykes, & Caitlin Gabor; NSF IOS 2307683)

Climate change can have harmful impacts on sensory systems, making it hard for animals to sense their environment, find food, and attract mates.  This project identifies the specific ways in which climate change impacts the sensory biology and behavior of freshwater fish and uses that knowledge to develop tools to enhance the survival of desert fishes in the southwestern US. The project begins by measuring the effects of temperature, acidity, water flow rate, and lighting shifts on zebrafish senses. Zebrafish have been well-studied as models for human disease and as sentinels for pollution, such that the results of this project will shed light on the detailed physiological mechanisms underlying the effects of climate change on aquatic animals.  For example, desert fishes in Arizona are being severely threatened by climate change and by the introduction of non-native fishes. Arizona Game and Fish Department researchers have been exploring solutions that involve raising native fishes in hatcheries for future reintroduction into the wild. This project contributes directly to those efforts by using zebrafish to test and develop ways to enhance sensory resilience by manipulating stress, reproductive state, and experiences, and by comparing the sensory abilities of native and non-native desert minnows. In addition, the project partners with the Arizona Game and Fish Department to share information on desert native fishes with local anglers, K-12 students, and teachers.

Acidification impedes olfaction in aquatic animals, increased temperature impairs tactile sensitivity, and murky water can hamper vision. However, sensory systems are malleable and intertwined, such that when one sensory system becomes unreliable or ineffective, animals may compensate by relying more heavily on other senses. Such compensation may be enhanced or limited by underlying physiological mechanisms that link sensory systems to each other and to other organismal functions. This project tests whether and to what degree sensory systems are resilient to ecological shifts associated with climate change in aquatic habitats, making use of the expansive genomic toolkit available for zebrafish to place the results in a rich and broad context of cutting-edge neuroscience and genomics research. In addition, the project tests whether resilience can be enhanced by manipulating hormone physiology and recent sensory experiences. To solidify a foundation for future collaboration with Arizona Game and Fish Department scientists, the project also tests whether sensory differences can explain why native desert fishes survive better than do non-natives in streams with intermittent flow. The project leadership team includes a diverse team of researchers, and engages students in all aspects of the research, including summer internships, career development opportunities in wildlife and biomedical science, and course-based research experiences.

Multimodal communication and resilience to climate change in Sceloporus lizards

(with Cristina Romero-Diaz, Stephanie Campos, Alison Ossip-Drahos, Jake Pruett, & Diana K. Hews)

xxxx