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Behavioral drive or behavioral inhibition in evolution: subspecific diversification in Holarctic passerines
Daniel Sol1, D Gray Stirling, Louis Lefebvre
1Department of Biology, McGill University, 1205 Avenue Docteur Penfield, Montréal, Québec H3A 1B1, Canada. d.sol@creaf.uab.es
Evolution; International Journal of Organic Evolution
|March 11, 2006
Summary
Large brains in birds are linked to more evolutionary diversification. This suggests behavioral changes, driven by brain size, directly promote species evolution, supporting the behavioral drive hypothesis.
Area of Science:
- Evolutionary biology
- Animal behavior
- Ornithology
Background:
- Behavioral changes are hypothesized drivers of evolutionary diversification.
- Empirical evidence and mechanisms linking behavior to diversification remain debated.
- The behavioral drive hypothesis suggests behavior influences evolutionary divergence.
Purpose of the Study:
- To empirically test the hypothesis that behavioral changes drive evolutionary diversification.
- To investigate the role of relative brain size as a proxy for behavioral plasticity.
- To examine the direct and indirect pathways linking behavior to diversification.
Main Methods:
- Comparative analysis of Holarctic passerine birds.
- Correlation of relative brain size (as a proxy for behavioral change propensity) with subspecific diversification.
- Path analysis to disentangle direct and indirect effects on diversification.
Main Results:
- Birds with larger relative brain sizes exhibited greater subspecific diversification.
- This effect was largely independent of other known diversification mechanisms.
- Path analysis indicated relative brain size directly influences diversification, not indirectly via range expansion.
Conclusions:
- Relative brain size, indicative of behavioral plasticity, is a significant factor promoting evolutionary diversification in passerines.
- Behavioral changes appear to directly facilitate evolutionary divergence, supporting the behavioral drive hypothesis.
- Findings provide empirical support for the long-standing hypothesis on the role of behavior in evolution.
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