NSF IBN95-07514 The Role of Mate Choice in Avian Speciation Nancy Tyler Burley, Principal Investigator A question of central interest to scientists studying the process of evolution is how the formation of new species ("speciation") occurs. Common mechanisms of speciation involve physical isolation of populations for long periods of time: when sufficiently isolated such that virtually no migration occurs between populations, populations regularly diverge in their traits. If isolation continues long enough, the result is speciation. Even occasional migration between populations, however, leads to gene exchange that prevents genetic divergence of populations from occurring, at least when the consequence of migration is joint reproduction of individuals derived from different populations. Thus, the tendency of organisms to accept as mates those individuals born in different populations should affect the probability and rate of speciation. For organisms with good powers of dispersal, physical isolation between populations may occur rarely, and mate choice for members of one's natal population could have an important role in speciation processes. This study experimentally investigates the occurrence and significance of mate preferences for natal population in two populations of longtailed finches. The longtailed finch is a small songbird native to northern Australia; although it is a strong flier, natural populations occurring at short distances from one another are highly distinctive. Preliminary work has established that birds from one population refuse to mate with birds from a different population. Additional work will determine the causes and functions of this preference for natal population. Research will include investigation of the cues birds use to recognize birds from their own population; how early life experiences may modify a bird's p erception of what constitutes "its own" population; and the role of preferences for associating with kin in these population preferences. Results of these experiments will be relevant to several broad areas of contemporary scientific exploration in biology, including population biology, evolution, ecology, and animal behavior. Results may be useful in furthering our understanding of captive breeding of wild animals and management of threatened species.
