Multiple behavioral mechanisms shape development in a highly social cichlid fish

Area of Science:

• Behavioral Ecology
• Neuroendocrinology
• Animal Behavior

Background:

• Early-life social experiences are critical for shaping adult phenotypes.
• The specific behavioral mechanisms linking early social life to adult outcomes are not well understood.
• Social behavior and stress axis function are key areas influenced by early experiences.

Purpose of the Study:

• To investigate how varying early-life social experiences affect juvenile behavior and stress axis function in cichlid fish.
• To determine the impact of social partner number and social stability on behavioral development.

Main Methods:

• African cichlid fish (Astatotilapia burtoni) juveniles were exposed to different social conditions: stable pairs, stable groups, and socialized pairs with rotating partners.
• Behavioral assays included open field exploration, social cue investigation, and assessments of dominant and subordinate behaviors.
• Water-borne cortisol levels were measured to assess stress axis function.

Main Results:

• Significant treatment differences were observed in all behavioral assays, but not in cortisol levels.
• Principal component analysis revealed behavioral syndromes sensitive to early social experience.
• Increased social partner number correlated with higher exploratory behavior and social interaction.
• Social instability (socialized pairs) was associated with increased dominance and reduced territoriality.

Conclusions:

• Early-life social experiences, particularly partner number and social stability, profoundly influence behavioral development in cichlids.
• Behavioral syndromes emerge that are shaped by the quantity and nature of early social interactions.
• These findings highlight the lasting impact of early social environments on phenotype, even without significant changes in stress hormone levels.