Evolutionary adaptation to heatwaves in an aquatic grazer

Climate change makes exceptionally hot summer periods (i.e., heatwaves) more common. This is a serious threat to populations of many species. Whether or not populations of organisms can survive under climate change depends on their ability to evolutionarily adapt to tolerate heatwaves. This project examines this process in a freshwater snail Lymnaea stagnalis that is common in lakes and ponds. First, the project examines whether snails show evolutionary potential by testing if snail individuals differ in their responses to high temperature and if the ability of snails to tolerate high temperature is inherited from parents to offspring. Such variation would provide the required raw material for evolutionary change. Second, the project examines how natural selection operates on snails responses to heatwaves by testing if snails with the highest thermal tolerance produce the highest number of offspring. If the above two requirements are met, evolutionary change over generations is possible. Lastly, the project examines if snail populations in nature differ in their responses to heatwaves depending on how common heatwaves are in their habitats. This reveals if snails from hotter habitats have evolved to tolerate high temperatures better than snails from cooler environments.