Contributed Symposium

Evolutionary emergence of vocal complexity in finches: sexual selection and relaxed selection as two factors

[Speaker] Okanoya, Kazuo:1
1:The University of Tokyo (Japan)

Vocal learning is a rare trait which appears among distantly related taxa of birds and mammals. I suggest two factors are crucial in the emergence of vocal learning. One is sexual selection and the other is relaxed selection. Sexual selection can promote complex behavior as an index of vigor of the individual. Relaxed selection can advance complex behavior through the elimination of environmental pressures, such as predation risk and feeding cost. As a behavior becomes complex, it can become a learned trait via a reverse Baldwinian effect. This can lead to the emergence of vocal complexity. I illustrate these points by using our comparative study on the evolution of complex songs in wild and domesticated Bengalese finches. In this species, preference by females (sexual selection) enhanced song complexity under domestication (relaxed selection). This behavioral change is also associated with changes in brains and stress reactions. (Supported by Kakenhi #15K14581)
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