Can the two Paramecium species prey on each other?

No, Paramecium species won’t prey on each other

Paramecia eat microorganisms that are smaller than them, like bacteriaalgae, and yeasts. However, Paramecium species won’t prey on each other. But two Paramecium species may compete for limited resources (nutrients and spaces).

What is the Competitive Exclusion Principle?

Russian biologist Georgy Gause (1910-1986) proposed the Competitive Exclusion Principle, sometimes referred to as Gause’s law. This principle is based on experimental work done with mixed cultures of two paramecium species: P. aurelia and P. caudatum. This principle asserts that two species competing for the same limiting resource cannot coexist at constant population values. One will be slightly more efficient than the other and will reproduce at a higher rate as a result (in this experiment, P. aurelia reproduce faster than P. caudatum). The fate of the less efficient species is local extinction (in this case, P. caudatum).

This principle became fundamental to the science of ecology and population behavior. For example, paleoanthropologists speculate that the extinction of Homo neanderthalensis was due to its disadvantage in the competition with our ancestors (Homo sapiens).

Competitive exclusion principle two paramecium

[In this figure] The demonstration of the competitive exclusion principle using two Paramecium species.
P. aurelia is the smaller but fast-growing species. P. caudatum is bigger but reproduce slowly. Both species grow happily in pure culture. However, once two species are mixed, even P. aurelia only has a slight reproductive advance, P. aurelia quickly compete and weed out P. caudatum.

Entended read:

Where can you find paramecia

The Natural Habitation and Cultivation of Paramecium

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