To determine how animals will respond to climate change, we must first understand the evolution of heat and cold tolerance. Large animals are particularly challenged by temperature changes, as they have a disproportionately large change in body size from young to adult. As young animals, their small bodies make them vulnerable to cold but resilient to heat. Conversely, the large bodies make adults resilient to cold and vulnerable to heat. In this project, we use the world's largest bird, the ostrich, as a representative of large warm-blooded animals and map the genes that are important for their persistence when it gets really hot and cold for both young and adults. The ostrich is unique in that it reproduces in both hot areas such as the Kalahari Desert and temperate regions such as the Cape of Good Hope, and can thus provide insight into what is required of different life-stages in extreme environments. This project will give us an understanding of how large animals adapt to temperature changes, and which life stages set the limits to this adaptation. This will give us unprecedented insight into the potential and limitations for both wild and domesticated large animals to adapt to a future more variable climate.
We will test two hypotheses
a) Heat and cold resilience are mechanistically linked causing thermoregulatory trade-offs.
b) Differences in selection for cold and heat resilience across life will constrain responses to fluctuating climates.
To test these hypotheses, we will 1) identify the genes important for heat and cold resilience in young and older individuals, 2) determine the associated molecular and physiological mechanisms involved in trade-offs between heat and cold tolerance, and 3) establish the role of these mechanisms in adaptation to natural local climatic conditions.
