Brain evolution in social insects: advocating for the comparative approach

Area of Science:

• Evolutionary biology
• Neuroscience
• Behavioral ecology

Background:

• Sociality is a major evolutionary transition, but its impact on brain evolution is not well understood.
• Previous studies often used broad measures like relative brain size, overlooking specific neural adaptations.
• Hymenoptera offer a diverse model system, ranging from solitary to highly social species.

Purpose of the Study:

• To propose a more refined approach for studying the role of sociality in nervous system evolution.
• To advocate for the use of specific neural traits at cellular, circuit, and molecular levels.
• To integrate advances in neuroethology and phylogenetic comparative methods.

Main Methods:

• Reviewing existing literature on sociality and brain evolution.
• Highlighting the limitations of brain size and volumetric analyses.
• Proposing the use of phylogenetic comparative methods applied to specific neural traits.

Main Results:

• Current approaches to sociality and brain evolution lack specificity.
• Brain size is an insufficient metric for understanding neural evolution driven by sociality.
• Specific neural traits (cellular, circuit, molecular) are more robust for evolutionary analysis.

Conclusions:

• Future research should focus on detailed neural traits rather than general brain composition.
• Phylogenetic comparative methods are crucial for analyzing trait evolution in social insects.
• This approach will provide a clearer understanding of how sociality shapes nervous system evolution.