Heterogeneous selection on a heritable temperament trait in a variable environment.

Area of Science:

• Evolutionary ecology
• Behavioral genetics
• Animal behavior

Background:

• Temperament traits are crucial for understanding behavioral variation.
• Exploration behavior in a novel environment (EB) is a key temperament trait in evolutionary ecology.

Purpose of the Study:

• To investigate the genetic basis and selective consequences of individual variation in exploration behavior (EB) in a wild population of great tits (Parus major).
• To determine if natural selection acts differently on EB across various temporal and spatial scales and environmental contexts.

Main Methods:

• Quantitative genetic analysis using a restricted maximum likelihood-based animal model with a long-term pedigree.
• Estimation of lifetime reproductive success to assess selection pressures.
• Analysis of exploration behavior using two distinct assays (8-min and 2-min) to ensure robustness and comparability.

Main Results:

• Exploration behavior (EB) showed moderate heritability, with significant contributions from permanent environment effects.
• Weak negative directional selection on EB was observed in females in one breeding year, driven by recruitment.
• Heterogeneous selection on EB in males was linked to fecundity along gradients of breeding density and habitat quality.

Conclusions:

• Individual variation in exploration behavior is influenced by both genetic and substantial permanent environmental effects.
• Natural selection on exploration behavior is highly context-dependent, primarily evident along specific environmental gradients.
• Understanding the evolution of exploration behavior requires considering its interaction with the environment.