Primate brain architecture and selection in relation to sex

Area of Science:

• Neuroscience
• Evolutionary Biology
• Primatology

Background:

• Mammalian social and competitive demands differ between sexes, influencing brain structure evolution.
• Sexual selection on males may affect sensory-motor and aggression pathways.
• Female social selection may influence brain regions related to social navigation and resource acquisition.

Purpose of the Study:

• To investigate the impact of sex-specific selection pressures on primate brain architecture.
• To determine if sexual selection on males and social selection on females have differential effects on brain structures.
• To explore the relationship between social behavior and brain evolution in primates.

Main Methods:

• Analysis of brain structure sizes in relation to male intra-sexual selection and female social group size.
• Correlational analysis to identify brain regions associated with specific selection pressures.
• Comparative study across anthropoid primate species.

Main Results:

• Male intra-sexual selection positively correlated with brain structures for autonomic functions, sensory-motor skills, and aggression pathways.
• Relative neocortex size positively correlated with female social group size, but negatively with male group size.
• No correlation found between male intra-sexual selection and relative neocortex size.

Conclusions:

• Sexual selection on males and social selection on females have distinct effects on primate brain evolution.
• Male-driven selection is linked to physical conflict adaptations, while female sociality drives socio-cognitive skill evolution.
• Primate brain architecture results from ecological, social, and sex-specific pressures, underscoring the need for sex-specific data.