Linking fearfulness and coping styles in fish.

Area of Science:

• Comparative psychology
• Animal behavior
• Neuroendocrinology

Background:

• Consistent individual differences in personality, including emotional reactivity and fearfulness, are observed across vertebrates.
• Coping styles and behavioral syndromes, indicative of personality, have been documented in teleost fishes, suggesting evolutionary conservation.
• The functionalist approach posits emotions evolved for adaptive behavioral responses to stimuli, but links between personality and fear expression are poorly understood across diverse species.

Purpose of the Study:

• To investigate the relationship between individual coping styles and fear responses in Nile tilapia (Oreochromis niloticus).
• To determine if personality traits predict specific fear-related behaviors and physiological stress indicators in fish.
• To explore the evolutionary breadth of the connection between personality and emotional states like fear.

Main Methods:

• Screening Nile tilapia for distinct coping styles (e.g., proactive vs. reactive).
• Utilizing an avoidance learning paradigm where fish escape a signaled aversive stimulus.
• Measuring fear responses, including neophobia, recovery of feed intake, and post-stress cortisol levels.

Main Results:

• Individual variation in coping style significantly predicted fear responses in Nile tilapia.
• Fearful individuals exhibited traits such as neophobia and delayed recovery of feeding in novel environments.
• Higher post-stress cortisol levels were observed in more fearful individuals, indicating physiological stress.

Conclusions:

• Individual differences in coping style are a reliable predictor of fear responses in Nile tilapia.
• Emotional reactivity and appraisal are integral components of animal personality, extending across the vertebrate subphylum.
• These findings support the evolutionary conservation of personality-trait-emotion links in vertebrates.