The genus Uroleucon, and the related genus Macrosiphoniella, represent a large Tertiary radiation of aphids, with a total of about 300 species distributed throughout the world, primarily on host plant species in the family Asteraceae. A molecular phylogenetic study was conducted to identify major clades within Uroleucon and to address the cladistic validity of current subgeneric categories, the evolution of host plant associations, the age of origin, and intercontinental movements in this genus. The seventeen study species included members of the three major subgenera of Uroleucon, species from Europe and North America, one member of Macrosiphoniella, and two outgroups. Data consisted of DNA sequences for three mitochondrial regions and the nuclear gene EF1alpha, for a total of 4287 sites. Nodes supported strongly in both parsimony and maximum likelihood analyses suggest that: (1) Nearctic Uromelan are a monophyletic group branching near the base of the genus and not related to European Uromelan, (2) the New World subgenus Lambersius is possibly monophyletic but is not a tightly related group and is not closely related to other North American species, and (3) Nearctic members of subgenus Uroleucon are a closely related monophyletic group not allied with Nearctic Uromelan or Lambersius. Instead they represent a separate colonization by an Old World ancestor, as they are nested within a strongly supported clade containing European members of both subgenera Uroleucon and Uromelan. Neither of these subgenera is monophyletic. Molecular clock calculations, based on calibrations of mitochondrial divergences from other insects, suggest that Uroleucon + Macrosiphoniella is a relatively recent radiation, probably no more than 5±10 million years old. Although largely con®ned to Asteraceae, this clade did not radiate in parallel with its host plants. Rather, lateral movement between lineages of Asteraceae must have occurred repeatedly. R Systematic Entomology (1999) 24, 85±93

Ornaments used in courtship often vary wildly among species, reflecting the evolutionary interplay between mate preference functions and the constraints imposed by natural selection. Consequently, understanding the evolutionary dynamics responsible for ornament diversification has been a longstanding challenge in evolutionary biology. However, comparing radically different ornaments across species, as well as different classes of ornaments within species, is a profound challenge to understanding diversification of sexual signals. Using novel methods and a unique natural history dataset, we explore evolutionary patterns of ornament evolution in a group—the birds-of-paradise—exhibiting dramatic phenotypic diversification widely assumed to be driven by sexual selection. Rather than the tradeoff between ornament types originally envisioned by Darwin and Wallace, we found positive correlations among cross-modal (visual/acoustic) signals indicating functional integration of ornamental traits into a composite unit—the “courtship phenotype.” Furthermore, given the broad theoretical and empirical support for the idea that systemic robustness—functional overlap and interdependency—promotes evolutionary innovation, we posit that birds-of-paradise have radiated extensively through ornamental phenotype space as a consequence of the robustness in the courtship phenotype that we document at a phylogenetic scale. We suggest that the degree of robustness in courtship phenotypes among taxa can provide new insights into the relative influence of sexual and natural selection on phenotypic radiations.

Birds of paradise (Aves: Paradisaeidae) exhibit extreme differences among taxa in courtship-related form (i.e. courtship phenotype). In the genus Parotia, the courtship phenotype is organizationally modular and this property may play an important role in the evolution of phenotypic disparity among taxa. The present study investigates variational aspects of phenotypic modularity in the Parotia by examining the structure and composition of courtship form in a comparative context. First, a module-based model of male display-phenotypes is compiled for four biological species to facilitate phenotypic comparison. Models are constructed using data from existing phenotype ontologies and associated video-vouchers. Next, a phylogenetic analysis of displayphenotype data is performed using a matrix of 47 etho-phenotypic characters coded for eight Parotia and out-group taxa. Analysis yields one tree, length 60 (CI = 0.83; RI = 0.85). The results demonstrate variation among taxa to be greater at higher-levels of phenotypic integration (i.e. among display-modules) than at intermediate and lower-levels (i.e. among phase-and element-modules). Three display-modules and five of six phase-modules were present in the common ancestor and complexity has increased through time as the displaymodules became dissociated into subunits that diverged independently. The history of Parotia evolution involves numerous instances of duplication and divergence of etho-phenotypic modular components and likely reflects the same processes that have contributed to the pronounced phenotypic disparity within the entire bird of paradise radiation.

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