Talk by prof. Kazuo Okanoya

Song complexity in Bengalese finches: domestication, epigenetics, and stress reactions

Abstract

The Bengalese finch (BF; Lonchura striata domestica) is a domesticated derivative of the wild white-rumped munia (WRM; L. s. swinhoei) with a captive-breeding history exceeding 270 years. Although early breeders selected chiefly for enhanced parental care and white plumage, the species’ courtship song diverged dramatically despite the absence of direct selection on vocal traits. WRMs deliver song syllables in an almost stereotyped order, whereas BFs recombine syllables with far greater sequential flexibility, producing strikingly complex song. We argue that this complexity arose through the interaction of two processes: (i) domestication relaxed behavioural constraints, fostering neural plasticity and heightened social tolerance, and (ii) female mate choice imposed indirect sexual selection, as females invest more reproductive effort when paired with males that sing complex songs. Together, these forces created the ecological and social conditions that propelled the cultural evolution of the elaborate song now emblematic of BFs. We review behavioral, morphological, and genetic evidence consistent with a domestication-syndrome framework to support this account.