Chaotic Red Queen coevolution in three-species food chains

Area of Science:

• Evolutionary biology
• Ecological dynamics
• Theoretical ecology

Background:

• Coevolution between antagonistic species often follows Red Queen dynamics, characterized by continuous adaptation and counteradaptation.
• Genetically driven Red Queen dynamics involve selective sweeps of beneficial mutations causing trait oscillations.
• Previous models demonstrated Red Queen cycles in simple prey-predator systems.

Purpose of the Study:

• To investigate how introducing a superpredator affects genetically driven Red Queen dynamics in a prey-predator system.
• To explore the conditions under which Red Queen cycles transition into chaotic dynamics.
• To hypothesize the ecological and evolutionary implications of Red Queen chaos in natural populations.

Main Methods:

• Mathematical modeling of a three-species food chain (prey, predator, superpredator) with coevolutionary dynamics.
• Analysis of selective sweeps and trait oscillations under Red Queen dynamics.
• Examination of the impact of prey evolution speed on the stability of the coevolutionary cycle.

Main Results:

• Embedding a coevolving superpredator into a prey-predator system frequently destabilizes the Red Queen cycle, leading to chaos, particularly when prey evolve rapidly.
• Red Queen chaos results in intrinsically unpredictable selection pressures, with the superpredator experiencing the highest unpredictability.
• This chaotic dynamic suggests populations may naturally exist at the edge of ecological chaos.

Conclusions:

• Genetically driven Red Queen chaos in food chains can explain the inherent unpredictability and potential instability observed in natural populations.
• Spatial spread of Red Queen chaos is predicted to drive local population divergence, even with environmental homogenization.
• This mechanism promotes long-term genetic diversity within ecological communities.