Sub-critical limits are viable alternatives to critical thermal limits

Area of Science:

• Ecophysiology
• Thermal Biology
• Climate Change Ecology

Background:

• Critical thermal limits are widely used but can harm study organisms.
• Sub-critical limits offer a less invasive alternative but data is scarce.
• Understanding thermal limits is crucial for predicting species responses to climate change.

Purpose of the Study:

• To assess if sub-critical thermal limits can serve as reliable proxies for critical thermal limits in ants.
• To determine if species-specific adjustments enhance the predictive power of sub-critical limits.
• To evaluate the utility of sub-critical limits for broad-scale ecological syntheses.

Main Methods:

• Measured and compared critical and sub-critical thermal limits in 2023 ants across 51 species.
• Utilized linear regression to assess the predictive relationship between sub-critical and critical limits.
• Incorporated species identity to evaluate gains in explained variance.

Main Results:

• Sub-critical limits alone were satisfactory linear predictors of individual and species critical limits.
• Including species identity significantly improved the predictive power of sub-critical limits.
• Species-specific conversion factors further enhanced the accuracy of critical trait estimation.

Conclusions:

• Sub-critical thermal limits are viable proxies for critical thermal limits in ants.
• Sub-critical limits can be integrated into broader ecological syntheses and used for metrics like warming tolerance.
• Acknowledging uncertainty is key, and phylogenetic signals can aid in inferring lower thermal traits.