Correlated evolution of personality, morphology and performance

Area of Science:

• Evolutionary biology
• Animal behavior
• Genetics

Background:

• Genetic correlations between traits can constrain independent evolution and lead to unexpected ecological outcomes.
• Animal personalities may be genetically linked to morphological and physiological traits due to shared underlying mechanisms and selective pressures.
• Little is known about genetic correlations between animal personality and non-behavioral traits.

Purpose of the Study:

• To investigate genetic correlations between personality, morphology, and locomotor performance in zebrafish (Danio rerio).
• To test adaptive hypotheses of correlational selection by selectively breeding zebrafish for distinct stress coping styles (bold vs. shy).

Main Methods:

• Selective breeding of wild zebrafish for proactive (bold) or reactive (shy) stress coping styles over four to seven generations.
• Comparison of morphology (caudal region size) and locomotor performance (fast-start escape) between the bold and shy lines.
• Analysis of individual-level phenotypic correlations to infer underlying genetic mechanisms (pleiotropy, linkage, disequilibrium).

Main Results:

• Bold zebrafish lines exhibited significantly larger caudal regions and higher fast-start escape performance compared to shy lines.
• Morphological and locomotor differences between personality lines matched predictions based on adaptive hypotheses.
• Correlated responses in locomotor performance were likely due to pleiotropy or gene linkage, while body shape changes may have involved linkage disequilibrium.

Conclusions:

• Evolution of animal personality can lead to simultaneous changes in morphology and performance.
• Conversely, selection on morphology or performance can influence personality traits.
• Understanding these genetic correlations is crucial for predicting evolutionary trajectories and ecological roles.