MOLECULAR INFORMATION ON BOWERBIRD PHYLOGENY AND THE EVOLUTION OF EXAGGERATED MALE CHARACTERISTICS

Mitochondrial DNA cytochrome b sequences of 849 base pairs are reported from eight species of Australian bowerbirds. These sequences are used with three from the literature (Edwards et al., 1991) to investigate bowerbird phylogeny using maximum parsimony and maximum likelihood methods. With respect to the three outgroup species, bowerbirds are shown to be monophyletic with high confidence using the bootstrap. The monogamous Ailuroedus crassirostris (which does not clear display courts) is indicated as the sister group to other bowerbirds. The maypole-builders (Amblyornis macgregoriae and Prionodura newtoniana) are significantly supported as a clade indicating a common origin for maypole type bowers, despite large differences in the design of these species' bowers. The avenue-builders (Sericulus chrysocephalus, Ptilonorhynchus violaceus, Chlamydera maculata and C. nuchalis) are also monophyletic. The pattern of divergence in avenue builders accords with the predictions of Gilliard's (1956, 1963) ''transferral effect''. The transference hypothesis is not supported by evidence suggesting that the dull plumage of Scenopoeetes is an ancestral condition in bowerbirds. The use of sticks to build bowers could have had a single evolutionary origin and been secondarily lost in Scenopoeetes, or evolved independently in the avenue and maypole builders.