Daily fluctuating temperatures decrease growth and reproduction rate of a lethal amphibian fungal pathogen in culture

Area of Science:

• Ecology
• Pathogen Biology
• Amphibian Conservation

Background:

• Emerging infectious diseases (EIDs) cause global species die-offs.
• Ecological approaches are key to understanding pathogen biology and EIDs.
• Pathogen exposure to variable temperatures can impact virulence, transmission, and persistence.

Purpose of the Study:

• To investigate the effect of a variable thermal environment on the reproductive life history traits of Batrachochytrium dendrobatidis (Bd).
• To assess Bd's response to simulated Yosemite toad breeding pool temperatures.

Main Methods:

• Collected temperature data from Yosemite toad breeding pools.
• Cultured Bd under a daily fluctuating temperature regime simulating natural conditions.
• Measured Bd growth, reproduction, fecundity, and viability.

Main Results:

• Bd growth and reproduction decreased in a diurnally fluctuating thermal environment compared to constant temperatures.
• Bd exhibited temperature-induced trade-offs under constant low and high temperature conditions.

Conclusions:

• Bd shows variable responses to dynamic thermal conditions.
• Realistic temperature fluctuations must be incorporated into studies of pathogen ecology and EIDs.