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2010Abstract
Analyses of the macroevolutionary correlates of brain structure volumes allow pinpointing of selective pressures influencing
specific structures. Here we use a multiple regression framework, including phylogenetic information, to analyze brain
structure evolution in 43 Tanganyikan cichlid species. We analyzed the effect of ecological and sexually selected traits for
species averages, the effect of ecological traits for each sex separately and the influence of sexual selection on structure
dimorphism. Our results indicate that both ecological and sexually selected traits have influenced brain structure evolution.
The patterns observed in males and females generally followed those observed at the species level. Interestingly, our results
suggest that strong sexual selection is associated with reduced structure volumes, since all correlations between sexually
selected traits and structure volumes were negative and the only statistically significant association between sexual
selection and structure dimorphism was also negative. Finally, we previously found that monoparental female care was
associated with increased brain size. However, here cerebellum and hypothalamus volumes, after controlling for brain size,
associated negatively with female-only care. Thus, in accord with the mosaic model of brain evolution, brain structure
volumes may not respond proportionately to changes in brain size. Indeed selection favoring larger brains can
simultaneously lead to a reduction in relative structure volumes.
11. Gonzalez-Voyer, A. and N. Kolm. 2010. Sex, ecology and the brain: Evolutionary correlates of brain structure volumes in Tanganyikan cichlids. PLoS ONE. 5(12), e14355.