Meeting Abstract
Climate change poses a threat to reptiles because hotter thermal environments can preclude times to achieve optimal body temperatures for activity. However, desert tortoises are typically not active during many hours of the day or year during which optimal body temperatures are achievable, and it seems that availability of adequate thermal environments for activity would be abundant even in warmer climates predicted for climate change. Upper Respiratory Tract Disease (URTD) caused by the bacterium Mycoplasma agassizii is also a threat to cause extinctions of desert tortoise populations. Our experimental research, and epidemiological theory, illustrate that this host-pathogen relationship is more likely an ancient enzootic relationship that cycles between a commensalism for healthy tortoises, and a pathogenic relationship in tortoises debilitated from too little food and water resources. Additionally, M. agassizii can be killed by temperatures that are very warm, but viable to desert tortoises. Thus, tortoises might exploit warm thermal environments to achieve “behavioral fever” to control M. agassizii, and climate warming may provide greater opportunities to employ this form of natural immunity. This process for controlling mycoplasmas seems to be limited to the warmer times of the year, but climate warming may increase the times when tortoises could control their pathogen through thermoregulation.
