Coevolution can reverse predator-prey cycles.

Area of Science:

• Ecology
• Evolutionary Biology
• Population Dynamics

Background:

• Classic Lotka-Volterra models predict prey peaks precede predator peaks in population cycles.
• These models assume fixed species traits, but coevolution can alter community dynamics.
• Coevolution can lead to novel dynamics like antiphase and cryptic cycles.

Purpose of the Study:

• To investigate if predator-prey coevolution can drive population cycles where predator peaks precede prey peaks.
• To identify conditions under which reversed-peak ordering occurs.
• To examine empirical evidence for these reversed cycles in natural systems.

Main Methods:

• Development of an eco-coevolutionary model.
• Analysis of conditions favoring extreme phenotypes, costly predator offense, and effective prey defense.
• Examination of real-world datasets from phage-cholera, mink-muskrat, and gyrfalcon-rock ptarmigan systems.

Main Results:

• The eco-coevolutionary model demonstrated that predator peaks can precede prey peaks.
• Reversed cycles emerge under specific selection pressures: favoring extreme phenotypes, costly predator offense, and effective prey defense against less offensive predators.
• Empirical data from multiple systems support the occurrence of these reversed-peak cycles.

Conclusions:

• Predator-prey coevolution can fundamentally alter community dynamics, leading to reversed population cycle ordering.
• Reversed-peak cycles serve as potential signatures of ongoing predator-prey coevolution.
• Coevolution can shape ecological interactions in unexpected ways, including reversing canonical oscillations.