Metabolic rate, context-dependent selection, and the competition-colonization trade-off

Area of Science:

• Ecology
• Evolutionary Biology
• Physiology

Background:

• Metabolism and pace-of-life are linked to survival, growth, and reproduction.
• Intraspecific variation in metabolic rates is common, even when controlling for body mass and temperature.
• Understanding how variable selection maintains metabolic rate variation in natural populations is crucial.

Purpose of the Study:

• To estimate selection on metabolic rates in a marine invertebrate under varying competitive conditions.
• To investigate the role of metabolism in mediating trade-offs across different environments.
• To determine if spatial heterogeneity in competition maintains metabolic rate variation.

Main Methods:

• Field-based estimation of selection gradients on metabolic rates.
• Utilizing a model marine invertebrate species.
• Comparing fitness landscapes in competition-free versus interspecific competition environments.

Main Results:

• Fitness landscapes for metabolic rate differed significantly between competitive environments.
• Interspecific competition favored higher metabolic rates and a faster pace-of-life.
• Metabolism mediated a competition-colonization trade-off, with high metabolism aiding competition and low metabolism aiding colonization in resource-limited scenarios.

Conclusions:

• Spatial heterogeneity in competitive regimes generates variable selection on metabolic rates.
• This variable selection likely maintains intraspecific variation in metabolic rates despite strong selection within specific environments.
• Metabolic rate variation is a key factor in ecological dynamics, influencing competition and colonization strategies.