Meeting Abstract
Polymorphic species provide an ideal system to study disease outcomes because different phenotypes can face diverse selection pressures within their shared environments. Previous studies have demonstrated that striped and unstriped morphs of the Eastern Red-Backed Salamander (Plethodon cinereus) vary in their seasonal activity and temperature preference. Compared to unstriped salamanders, striped salamanders experience lower mortality in cool temperatures and remain active on the forest floor as the temperature cools in the autumn. Capitalizing on this variation, we conducted a laboratory experiment in which we raised salamanders of both color morphs in cool (18C) and warm (24C) temperatures and then exposed them to a pathogenic chytrid fungus (Batrachochytrium dendrobatidis; “Bd“). Temperature is known to impact the growth rate of Bd and temperature can also mediate outcomes between amphibians and Bd. If striped salamanders are physiologically adapted to cool temperatures, we predicted that they would have lower Bd infection and prevalence compared to unstriped salamanders, even though Bd is thought to grow optimally in cool temperatures. In addition, we predicted that striped salamanders would have higher Bd infection and prevalence in warm temperatures compared to unstriped salamanders. Contrary to our predictions, striped salamanders had a higher Bd prevalence at cool temperatures and a lower prevalence at warm temperatures. Although these color morphs are known to differ in temperature preference, our results might indicate that they are not physiologically adapted to different thermal optima, at least not as measured within the context of our experiment.
