Adaptive evolution in locomotor performance: How selective pressures and functional relationships produce diversity

Area of Science:

• Evolutionary biology
• Comparative physiology
• Herpetology

Background:

• Phenotypic evolution often studies selective pressures in isolation.
• Interacting selective pressures are expected to cause trade-offs, limiting diversity.
• However, interactions may also promote phenotypic diversity.

Purpose of the Study:

• To explore the evolution of lizard locomotor performance under multiple selective pressures.
• To investigate the roles of foraging mode, predator escape, and habitat use in shaping performance phenotypes.
• To test whether interacting selection promotes or constrains phenotypic diversity.

Main Methods:

• Utilized the Ornstein-Uhlenbeck process to model phenotypic evolution.
• Analyzed selective pressures including foraging mode, predator escape, and habitat use.
• Examined variation in locomotor performance phenotypes across lizard species.

Main Results:

• A combination of selection for foraging mode and predator escape best explained performance variation.
• Habitat use had minimal explanatory power for locomotor performance.
• Evolving distinct performance abilities, previously thought correlated, is possible.
• The expected trade-off between maximal exertion and speed disappeared under joint selection.

Conclusions:

• Functional integration does not necessarily limit adaptive potential.
• Interactions among selective pressures can promote, rather than limit, phenotypic diversity.
• An integrative approach considering multiple selective influences provides a fuller understanding of adaptation and diversity.