Badyaev, A. V., University of Arizona, Tucson, USA, abadyaev@email.arizona.edu
Young, R. L., Yale University, New Heaven, USA, rlyoung@email.arizona.edu
Oh, K. P., University of Arizona, Tucson, USA, koh@email.arizona.edu
Addison, C. B., University of Arizona, Tucson, USA, caddison@email.arizona.edu

EVOLUTION ON A LOCAL SCALE: DEVELOPMENTAL, FUNCTIONAL, AND GENETIC BASES OF DIVERGENCE IN BILL FORM AND ASSOCIATED CHANGES IN SONG BETWEEN ADJACENT HABITATS

Divergent selection on traits involved in local adaptation and mating signals can facilitate population divergence. Because of its links to foraging morphologies and cultural inheritance, bird song can contribute strongly to maintenance of local adaptations. In two adjacent habitats - native Sonoran desert and urban areas - house finches forage on seeds that are highly distinct in size and hardness and require different bite forces and bill morphologies. We first document habitat-specific selection on bite force and find adaptive modifications of bill morphology and associated divergence in courtship song between the two habitats. Second, we document that ontogenetic tissue transformation in bill, but not skeletal traits, is accelerated in the urban population and that the mandibular primordia of the large-beaked urban finches express bone morphogenetic proteins (Bmp) earlier and at higher level than those of the desert finches. Further, we show that despite being geographically adjacent, urban and desert populations are nevertheless genetically distinct corroborating findings of early developmental divergence between them. Taken together, these results suggest that divergent selection on function and development of traits involved in production of mating signals, in combination with localized learning of such signals, can be very effective at maintaining local adaptations, even at small spatial scales and in highly mobile animals.

Oral presentation

Session #:G14
Date: Tuesday, 8/5/08
Time: 10:15 AM

Presentation is given by student: No