Lizards fail to plastically adjust nesting behavior or thermal tolerance as needed to buffer populations from climate...

Area of Science:

• Ecology and evolutionary biology
• Climate change adaptation
• Herpetology

Background:

• Phenotypic plasticity is a potential mechanism for species to adapt to environmental changes like climate change.
• Sceloporus tristichus lizards face reproductive challenges due to climate change, potentially requiring altered nesting behaviors or increased thermal tolerance.
• Previous modeling indicated a need for deeper nests, more shade, or higher embryonic thermal tolerance.

Purpose of the Study:

• To experimentally investigate the influence of maternal temperature on nesting behavior and embryonic thermal sensitivity in Sceloporus tristichus.
• To assess the capacity for phenotypic plasticity to facilitate adaptation to climate change in this lizard species.

Main Methods:

• Experimental manipulation of maternal temperatures during gestation and nesting.
• Measurement of nesting behavior, including nest depth.
• Assessment of embryonic thermal sensitivity through high-temperature exposure.
• Use of simulations to evaluate historical thermal limitations.

Main Results:

• Maternal temperature during gestation did not affect nesting behavior.
• Warmer temperatures during nesting led to reduced nest depth.
• Embryos from heat-stressed mothers exhibited increased sensitivity to high temperatures.
• Historical climate data suggest low temperatures, not high temperatures, have historically limited population development.

Conclusions:

• The observed phenotypic plasticity in Sceloporus tristichus may be insufficient to cope with projected climate change impacts.
• The plasticity required for adaptation has not been under sufficient selective pressure.
• Climate change may introduce novel stressors that current plasticity cannot buffer, potentially leading to reproductive failure.