Evolutionary ecology of intraspecific brain size variation: a review
Article first published online: 26 JUN 2013
© 2013 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.
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Ecology and Evolution
Volume 3, Issue 8, pages 2751–2764, August 2013
How to Cite
Ecology and Evolution 2013; 3(8): 2751–2764
- Issue published online: 12 AUG 2013
- Article first published online: 26 JUN 2013
- Manuscript Accepted: 7 MAY 2013
- Manuscript Revised: 6 MAY 2013
- Manuscript Received: 25 FEB 2013
- Academy of Finland. Grant Numbers: 134728, 128716
- Centre of Excellence in Evolutionary Genetics and Physiology. Grant Number: 129662
- Finnish School in Wildlife Biology, Conservation and Management
- Brain plasticity;
- brain size;
- natural selection;
- neural architecture;
- population differentiation
The brain is a trait of central importance for organismal performance and fitness. To date, evolutionary studies of brain size variation have mainly utilized comparative methods applied at the level of species or higher taxa. However, these studies suffer from the difficulty of separating causality from correlation. In the other extreme, studies of brain plasticity have focused mainly on within-population patterns. Between these extremes lie interpopulational studies, focusing on brain size variation among populations of the same species that occupy different habitats or selective regimes. These studies form a rapidly growing field of investigations which can help us to understand brain evolution by providing a test bed for ideas born out of interspecific studies, as well as aid in uncovering the relative importance of genetic and environmental factors shaping variation in brain size and architecture. Aside from providing the first in depth review of published intraspecific studies of brain size variation, we discuss the prospects embedded with interpopulational studies of brain size variation. In particular, the following topics are identified as deserving further attention: (i) studies focusing on disentangling the contributions of genes, environment, and their interactions on brain variation within and among populations, (ii) studies applying quantitative genetic tools to evaluate the relative importance of genetic and environmental factors on brain features at different ontogenetic stages, (iii) apart from utilizing simple gross estimates of brain size, future studies could benefit from use of neuroanatomical, neurohistological, and/or molecular methods in characterizing variation in brain size and architecture.