Investigating mechanisms and costs of increased temperature variation in tropical and temperate dung beetles

University Of Tennessee Knoxville, Knoxville TN

Investigators

Abstract

Temperature profoundly impacts animal physiology, thus temperature fluctuations has major consequences for survival and reproduction of species. Temperature fluctuations may be particularly challenging for animals that have evolved in relatively constant thermal environments, like tropical regions, compared to those that have evolved in thermally variable environments, like temperate regions. To understand how temperature fluctuations affect species from different thermal environments, this project will expose tropical and temperate dung beetles to increased temperature fluctuations and integrate data across levels of biological organization. Specifically, the researchers will quantify gene expression and physiological responses of tropical and temperate dung beetles to increases in temperature fluctuation and then investigate how species responses affect survival and reproduction. The results of this work will support a greater understanding of sensitivity of animals from different latitudes to environmental challenges. Broader impacts of the research include training of graduate and undergraduate students in physiology and ecology in the USA and at international field sites, thus strengthening the students' global networks. To communicate research to the public, the team will use a YouTube channel, to post research videos that are accessible to non-scientists. Team members will continue to host the annual Rocky Top BioBlitz at the University of Tennessee to help citizens learn about biodiversity in urban environments. Lastly, the research will add insect specimens to collections in the USA and Ecuador for teaching and research. Theory predicts that temperature fluctuations should have greater impacts on physiology and fitness than shifts in mean temperature alone, and these impacts should vary with the evolutionary history of the organism. This project applies transcriptomic and physiological data from tropical and temperate dung beetles to transform current understanding of energetic responses and fitness costs associated with increased temperature fluctuations for species separated by latitude. Specifically, the researchers will measure gene expression and physiological (i.e. metabolic rate) responses to increased temperature fluctuations. Energetic consequences of increased thermal fluctuations will then be quantified. Finally, fitness-related variables in response to increased temperature fluctuations will be evaluated. This project will lead to a better understanding of trade-offs between energy allocated to stress responses versus energy allocated to reproduction, providing a foundation for a more realistic model of the impacts of temperature fluctuations across latitude that can be replicated for other species. In addition, the research will provide key information on molecular mechanisms in tropical species and non-model organisms. 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.