Experimentally enhanced performance decreases survival in nature

Area of Science:

• Zoology
• Animal Physiology
• Ecology

Background:

• Superior locomotor performance offers survival and reproductive advantages in many species.
• In humans, exercise enhances health and longevity, but its impact on wild animal survival is unknown.
• Green anole lizards exhibit exercise responses, with trade-offs in reproduction and immunity.

Purpose of the Study:

• To investigate if enhanced locomotor performance through exercise training provides a survival advantage in wild green anole lizards.
• To determine if exercise training impacts survival rates in a naturalistic setting.

Main Methods:

• Male and female green anole lizards underwent sprint training, endurance training, or no training (controls).
• Trained and untrained lizards were released onto an isolated urban island in New Orleans, LA, USA.
• Survivorship of all lizards was monitored over the study period.

Main Results:

• Sedentary control lizards exhibited significantly higher survivorship compared to both sprint-trained and endurance-trained lizards.
• Exercise training led to a survival disadvantage for green anole lizards in this environment.

Conclusions:

• Locomotor capacity in green anoles appears optimized for current environmental demands to maximize survival.
• Increased investment in athletic performance via exercise training may move individuals into a suboptimal phenotypic space, reducing survival rates.