Labile evolution of display traits in bowerbirds indicates reduced effects of phylogenetic constraint

Abstract

SUMMARYBowerbirds (Ptilonorhynchidae) have among the most exaggerated sets of display traits known, including bowers, decorated display courts and bright plumage, that differ greatly in form and degree of elaboration among species. Mapping bower and plumage traits on an independently derived phylogeny constructed from mitochondrial cytochrome b sequences revealed large differences in display traits between closely related species and convergences in both morphological and behavioural traits. Plumage characters showed no effect of phylogenetic inertia, although bowers exhibited some constraint at the more fundamental level of design, but above which they appeared free of constraint. Bowers and plumage characters, therefore, are poor indicators of phylogenetic relationship in this group. Testing Gilliard's (1969) transferral hypothesis indicated some support for the idea that the focus of display has shifted from bird to bower in avenue-building species, but not in maypole-builders or in bowerbirds as a whole.

Co–option of male courtship signals from aggressive display in bowerbirds

“…Basolo 1995;Johnson 1999) and can also be used to test for di¡erences in the timing of the appearance of skrraa call functions in aggression and courtship. We mapped skrraa call use onto a robust phylogeny derived from cytochrome b sequence information (Kusmierski et al 1997). If aggressive calls evolved ¢rst, species using skrraa calls in aggression and courtship should be nested within a larger group using them only in aggression.…”

“…Figure 1. Phylogeny of the bowerbirds (Kusmierski et al 1997) onto which the presence ( + ), absence (7 ) or presence unknown (?) of skrraa calls in aggressive and courtship displays are mapped.…”

“…Behaviours of 15 species and subspecies at bowers were monitored (Kusmierski et al 1997) with a remote-controlled video camera system (Borgia 1995) that recorded courtship and, in some cases, aggressive behaviour at bowers. Microphones for sound recordings on video tape were placed at a constant distance (1m) above the display court.…”

“…The statistical analyses used regression, Monte Carlo simulation and the Proc MIXED module of SAS (SAS Institute, Inc. 1999) allowing analysis of unbalanced, nested comparisons. Maximumparsimony (MP) and maximum-likelihood (ML) ancestor reconstructions were developed with the MacClade (Maddison & Maddison 1992) and ANCML (Schluter et al 1997) programs, respectively, using genetic distances provided by Kusmierski et al (1997). ML reconstructions used two state variables and statistical signi¢cance was shown by absence of overlap of the con¢dence interval (95% or greater) with the midpoint value.…”

The evolution of courtship display repertoire size in the dabbling ducks (Anatini)

“…This hypothesis (Gilliard, 1956;Borgia, 1993;Kusmierski et al, 1993Kusmierski et al, , 1997 suggests that ornaments of various types are costly. There may be a tradeoff between display using one media and display using another (e.g.…”