Evolutionary Ecology of a Cave Dwelling Poeciliid Fish: The Roles of Darkness and Toxic Sulfur.

University Of Oklahoma Norman Campus, Norman OK

Investigators

Abstract

Extreme habitats require special adaptations. Populations of the Atlantic molly (Poecilia mexicana) have independently colonized two caves in Tabasco (Mexico) that harbor toxic levels of hydrogen-sulfide and dark conditions. Adaptations to dark environments, such as reduced pigmentation and eyes, are well known among cave organisms. However, how animals adapt to high levels of hydrogen-sulfide are not well understood. This research is designed to study life history evolution among closely-related molly populations that are found in extreme habitats of dark, hydrogen-sulfide waters found in caves, as well as in non-toxic environments that experience normal ambient light levels. The research examines fitness responses to environmental conditions in the field and in common garden experiments where environmental conditions are manipulated. By taking a functional approach to examine response of life history traits among a suite of closely-related taxa under different conditions, the research can make important contributions to understanding how organisms adapt to extreme environments, including the rather novel conditions found in hydrogen-sulfide rich aquatic environments. The project, which takes place in one of the poorest areas of Mexico, will be conducted in collaboration with several international colleagues including researchers from a small, Mexican university, the Universidad Intercultural in Oxolatan. The Oxolatan campus primarily serves underrepresented indigenous people. This project will provide field research training to local students from the Universidad Intercultural and provide opportunities for students and faculty from that campus to visit the University of Oklahoma for training and cultural exchange. In addition, undergraduate and graduate students from the University of Oklahoma will receive training as part of this project, including international research opportunities. Outreach to educate the local population using public talks and posters will also occur as part of this project. Results from this research will help protect the Cueva del Azufre as a globally unique habitat and cultural icon for the local Zoque tribe.