Does coping style predict optimization? An experimental test in a wild passerine bird.

Area of Science:

• Behavioral Ecology
• Evolutionary Biology
• Animal Reproduction

Background:

• Avian reproductive strategies are often considered individually optimized.
• However, environmental sensitivity varies among individuals, potentially altering optimal reproductive decisions.
• Coping styles, such as proactivity and reactivity, may influence an individual's ability to optimize brood size.

Purpose of the Study:

• To investigate if different coping styles (proactive vs. reactive) in great tits (Parus major) affect the optimization of reproductive decisions.
• To determine if environmental sensitivity, as indicated by exploratory behavior, influences the fitness outcomes of manipulated brood sizes.
• To test the hypothesis that reactive individuals perform optimally at their natural brood size, while proactive individuals may benefit from adjusted brood sizes.

Main Methods:

• Quantified exploratory behavior as a proxy for proactivity in a great tit population.
• Manipulated brood sizes, creating reduced, control, and enlarged conditions.
• Evaluated the fitness consequences of these manipulations across individuals with different coping styles.

Main Results:

• Reactive females achieved their highest fitness with their natural brood size.
• Proactive females exhibited the highest fitness when raising an enlarged brood.
• These results indicate that proactive females may produce sub-optimal brood sizes compared to their potential.

Conclusions:

• Coping style is a significant factor in determining optimal reproductive decisions and life-history strategies in birds.
• Proactive individuals may make reproductive decisions based on biased environmental perceptions or face energetic constraints.
• Understanding individual differences in environmental sensitivity is crucial for comprehending the evolution of reproductive strategies.