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Energy Allocation Explains How Protozoan Phenotypic Traits Change in Response to Temperature and Resource Supply
Andrea Perna1,2, Enrico S Rivoli2, Julia Reiss2,3
1IMT School for Advanced Studies Lucca Lucca Italy.
Ecology and Evolution
|August 6, 2026
Summary
Organisms adjust energy use to changing environments. Tetrahymena pyriformis acclimated to new temperatures and resources by altering cell size, restoring efficient energy allocation.
Area of Science:
- Ecology
- Evolutionary Biology
- Physiology
Background:
- Organisms must balance energy intake and expenditure for survival and reproduction.
- Environmental changes necessitate adjustments in behavior, physiology, or morphology.
- Understanding how multiple phenotypic traits interact with environmental factors to influence energy allocation is crucial.
Purpose of the Study:
- To develop a predictive framework for phenotype-environment interactions concerning energy allocation.
- To predict changes in metabolic rate and movement speed in response to temperature and resource availability.
- To differentiate between short-term (acute) and long-term (acclimation/adaptation) responses.
Main Methods:
- Exposed axenic populations of the ciliate Tetrahymena pyriformis to varying temperature and resource conditions.
- Measured population growth, cell size, respiration, and movement.
- Applied principles of energetic, biophysical scaling, and Boltzmann-Arrhenius equation.
Main Results:
- Acute temperature increases led to higher movement speeds and respiration rates.
- Within approximately 3.5 days, traits shifted towards original values, indicating acclimation.
- Cell size changes significantly impacted metabolic rate and movement costs, playing a key role in acclimation.
Conclusions:
- Phenotypic acclimation, particularly through cell size adjustments, helps restore efficient energy allocation in Tetrahymena pyriformis.
- Rapid changes in body size are an effective strategy for microbial consumers to cope with environmental shifts.
- The study provides a framework for understanding complex phenotype-environment interactions in energy allocation.
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