Thermal biology of newts (Notophthalmus viridescens) chronically infected with a naturally occurring pathogen

1.Newts chronically infected with an Ichthyophonus-like organism selected warmer temperatures than healthy newts, consistent with prior work on behavioral fever, though the magnitude of the difference was much greater than reported in other studies.2.The large difference in selected temperature (>11 °C) may be a consequence of the chronic nature of the Ichthyophonus infection in newts from the field.3.Healthy newts exhibited a higher thermal tolerance than infected newts, reflecting the greater morbidity of infected newts.4.Little is known about the course of Ichthyophonus in newts, and the possible consequences of changes in thermal biology are discussed.