The repeatability of metabolic rate declines with time

Area of Science:

• Evolutionary biology
• Physiological ecology
• Quantitative genetics

Background:

• Individual variation in metabolic rate is fundamental to evolutionary processes and organismal performance.
• Repeatability, a measure of trait consistency over time, is essential for a trait to be subject to natural selection.
• Previous meta-analyses indicated that metabolic rate is generally repeatable.

Purpose of the Study:

• To update and expand upon previous meta-analyses of metabolic rate repeatability.
• To investigate how the time interval between measurements affects the repeatability of metabolic rate.
• To assess the evolutionary implications of temporal variation in metabolic rate.

Main Methods:

• Conducted a meta-analysis incorporating newly published data on metabolic rate repeatability.
• Quantified the relationship between the time interval separating measurements and observed repeatability.
• Calculated repeatability as the ratio of between-individual variance to total phenotypic variance.

Main Results:

• The overall repeatability of metabolic rate remains significant, consistent with prior studies.
• A significant negative correlation was found between the time interval and metabolic rate repeatability.
• Longer intervals between measurements lead to lower estimates of metabolic rate repeatability.

Conclusions:

• While metabolic rate exhibits repeatability, its consistency diminishes over extended periods.
• The evolutionary potential of metabolic rate variation may be constrained by temporal instability.
• Future studies should carefully consider measurement intervals when assessing metabolic rate repeatability for evolutionary analyses.