How a Trade-off Constrains the Range of the Trinidadian Guppy
An organism's current suite of traits can explain it's current range, but tradeoffs between these traits can explain why that range does not expand. Across a salinity gradient in the rivers of Trinidad one finds strikingly consistent ranges in two species of guppy, Poecilia reticulata & Poecilia picta. P. reticulata avoids brackish water entirely whereas P. picta spans the entire gradient, but only marginally coexists with P. reticulata in freshwater. Reciprocal transplant field studies, common garden studies, and behavioral experiments in the lab support the hypothesis that a genetically based tradeoff between salinity tolerance and interspecific competitive ability with P. picta may limit P. reticulata's range in nature.
Currently, my collaborators and I are expanding this project in multiple dimensions. In collaboration, with former undergraduate mentee Kyndall Zeller, we are investigating how the P. reticulata/P. picta species interaction changes across different salinities because we know that species interactions change depending on the context and this can have important ecological and evolutionary ramifications. Further, using transcriptomics, we have identified a potential biological network underlying the salinity tolerance/competition trade-off. Lastly, in collaboration with Andrew Whitehead's lab at UC Davis, we are using population genomics to investigate how salinity shapes population structure in P. picta. |
The Evolutionary Ecology of Colonizing Fence Lizards
As colonizing populations invade new places, they encounter novel environments and selective pressures. The phenotypic response of the colonizing population to the new environment is a product of the plastic response to the environment and subsequent evolution that is in part a response to the new selective pressures. Cases in which the connection between the selective pressures of the new environment and the phenotypic response of the population is clear, have become powerful examples of adaptation in nature. In this project, my collaborators and I are taking advantage of a system in which the ancestral "dark soil" morph of the Southwestern Fence lizard (Sceloporus cowlesi) has invaded two unique habitats, the Carrizozo lava flow & White Sands dune system, to learn more about how the environment influences the phenotype of colonizing populations. Our research focuses on the color differences, the behavioral differences, and differences in microbiome between the three S. cowlesi morphs.
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Heat and Drought Tolerance in European Insects
Global climate change is altering many different climatic factors, not just temperature. For example, droughts are increasing in intensity and duration alongside increases in temperature. Organisms, especially small ectotherms like insects, are now faced will the duel challenge of managing both heat stress and stress due to water loss. Furthermore, these two traits (heat tolerance and desiccation tolerance) are likely to interact in complex ways, making the organism's physiological response and corresponding changes in performance and fitness difficult to predict. To better understand how insects will respond to this threat, I am measuring heat tolerance, desiccation tolerance, and metabolic rate in wide-spread pollinating insects across a latitudinal gradient in western Europe. This data will used to create models that will help us better predict insects overall response to climate change. Lastly, we will use previous methodological developments when collecting and analyzing this data.
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