Nancy Burley: UC Irvine Department of Ecology & Evolutionary Biology

Sexual imprinting, a process by which early contact with parents shapes the mate preferences of developing young, has been widely documented among birds and has been reported for other vertebrates, especially mammals (including humans). Historically, studies of imprinting have emphasized causal and ontogenetic perspectives, with function and evolutionary consequences receiving less attention. Recent quantitative models have investigated a possible role for sexual imprinting in vertebrate speciation processes, but little empirical support for this possibility has been provided. Moreover, recent studies suggest that sensory drive processes exert strong, unlearned influences on mate preferences which might override tendencies to imprint on novel traits that emerge in incipiently diverging populations. Here I report results of several experiments designed to evaluate the tendency of both sexes of zebra finches to imprint on novel traits of parents with otherwise normal phenotypes. The novel (experimental) traits are crests of various colors and patterns. Previous research (Burley & Symanski 1998) indicates that female zebra finches reared with wild-type (uncrested)parents have sensory biases favoring white-crested males; normally reared males lack this bias and favor uncrested females. By rearing young with crested parents, I investigated how sensory drive and imprinting processes interact. Results suggest that imprinting responses of both sexes may vary considerably with the perceived information content of experimentally manipulated traits, and that some evolutionarily novel traits may promote reproductive isolation in diverging populations.
http://www.bec.ucla.edu/papers/Burley_5.1.06.pdf