Did Gause Have a Yeast Infection?

Area of Science:

• Ecology
• Microbiology
• Mathematical Biology

Background:

• Predator-prey dynamics are fundamental in ecology.
• Gause's 1930s work on Paramecium and yeast is a classic but unverified model system.
• Empirical validation of Paramecium growth on yeast is lacking.

Purpose of the Study:

• To empirically evaluate Paramecium aurelia's ability to ingest and grow on various yeast species.
• To parameterize a predator-prey model based on ingestion rather than growth.
• To reassess the suitability of the Paramecium-yeast system for ecological modeling.

Main Methods:

• Ingestion and growth trials of Paramecium aurelia with eight yeast species.
• Empirical parameterization of a predator-prey model.
• Comparison of model simulations with historical Gause data.
• Review of Gause's experimental methods and data integrity.

Main Results:

• Paramecium aurelia ingested yeast but could not grow on it.
• Model simulations did not replicate Gause's historical data.
• Gause's experiments were likely contaminated with bacteria, and data were manipulated.
• Several other ciliate species also cannot grow on yeast.

Conclusions:

• The Paramecium-yeast system is unsuitable for empirical or theoretical predator-prey modeling.
• Historical data from Gause are unreliable due to experimental contamination and data manipulation.
• Alternative ciliate species (Tetrahymena pyriformis, Colpidium striatum) can grow on yeast and may serve as better models.