Molecular and Evolutionary Mechanisms Underlying Desiccation Resistance Across Drosophila Species

Michigan State University, East Lansing MI

Investigators

Abstract

Understanding how current species adapt to extreme environments such as the desert can help determine how the species could evolve in response to environmental changes. As environments get warmer and drier due to rapid climate change, organisms must adapt to these changes to survive and thrive in these new conditions. Insects use a lipid layer on their body surface to prevent water loss and withstand desiccation stress. The proposed study will investigate the association between desiccation resistance and chemical properties of this lipid layer across insect species. Furthermore, this study will use a desert-dwelling insect species as a model to investigate the physiological and genetic mechanisms underlying how insects can evolve very high desiccation resistance. Since components of this lipid layer also function as pheromones in many insect species, evolutionary changes in these components can lead to changes in mating successes. Results from this study will provide empirical evidence in determining how environmental adaptation can lead to changes in mating behaviors and reproductive isolation between insect species. The project will use existing infrastructure to promote STEM teaching, training, and learning to students, teachers, and the public through workshops, videos, and science fair participation, as well as broaden full participation of underrepresented minorities. Adaptation to different environments and habitats is key to long-term species persistence. Decreasing water loss is important for organisms adapting to different terrestrial environments. In Drosophila fruit flies and other terrestrial insects, this ability to prevent water loss is crucial. Previous studies suggested that cuticular water loss accounts for the majority of water loss in insects and hypothesized that differences in cuticular hydrocarbon (CHC) content account for differences in desiccation resistance between mesic and desert species. However, the specific association between different CHC components and desiccation has not been established, and the genetic mechanisms underlying the evolution of these CHC components that confer high desiccation resistance have not been elucidated. This proposed study will investigate how evolution of CHCs in insects affects desiccation resistance and elucidates the genetic mechanisms and evolutionary constraints that govern their evolution in a desert species, Drosophila mojavensis. As CHCs are dual traits that also have other functions such as mate recognition, the constraints that govern the evolution of these CHCs in these dual roles are not well understood. This project will also investigate how the functions of CHCs in desiccation resistance may affect mate recognition. Collectively, the long-term goal of this project is to elucidate the molecular and evolutionary mechanisms that enable species to withstand water loss and maintain water balance as our planet gets warmer and more arid in the next few decades. 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.