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Plumage Pattern (plumage + pattern)

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Life Sciences	100%

Selected Abstracts

Inferring the phylogeography and evolutionary history of the splendid fairy-wren Malurus splendens from mitochondrial DNA and spectrophotometry

JOURNAL OF AVIAN BIOLOGY, Issue 1 2009
Anna M. Kearns
The phylogeographic structure of the widely distributed arid and semi-arid Australian splendid fairy-wren Malurus splendens was investigated by using variation in plumage characters and mitochondrial DNA (mtDNA). We examined sequences of the mtDNA ND2 gene and used spectrophotometry to quantify chromatic variation in plumage in order to test the current morphology-based intraspecific taxonomy of M. splendens and to discriminate between hypotheses invoking allopatric and parapatric processes in the origin of diversity in the complex. Genetic diversity of M. splendens fell into three divergent geographically structured clades. One represents populations ascribed to the western subspecies M. s. splendens, the other populations of central M. s. musgravi and the third all eastern populations currently ascribed to M. s. emmottorum and M. s. melanotus. Plumage patterns clearly differentiate M. s. splendens and M. s. musgravi, and spectrophotometry identified a step-wise transition in spectra between M. s. melanotus and M. s. emmottorum. Congruence of patterns of phenotypic and genetic variation among western, central and eastern populations of M. splendens strongly suggests that these populations have diverged in allopatry on either side of historical biogeographic barriers in this region. Decoupled patterns of phenotypic and genetic diversity suggest that the divergence of M. s. melanotus and M. s. emmottorum may have occurred without periods of isolation perhaps in response to differences in local environmental conditions, or alternatively, mtDNA and plumage may have different rates of evolution. Critically, we encountered issues with the placement of the root of the M. splendens complex. The root was placed within the subspecies M. s. splendens separating its northern and southern populations and rendering the subspecies paraphyletic. [source]

Escape Behavior of Neotropical Homopterans in Response to a Flush,Pursuit Predator

BIOTROPICA, Issue 4 2004
Mark L. Galatowitsch
ABSTRACT Insect defenses against avian predators often include both a primary defense that reduces the probability of being attacked and a secondary defense, typically escape behavior, employed if the primary defense fails. Escape behavior, however, can make insects potentially vulnerable to specialized flush,pursuit predators. Neotropical Redstarts of the genus Myioborus (Parulidae) exploit insect escape behavior by using their contrasting black-and-white plumage and animated foraging behavior to startle insect prey that are then pursued and captured in flight. We examined how insect primary defense strategy and natural variation in Myioborus plumage pattern influence escape behavior in six species of homopterans from Monteverde, Costa Rica. The six homopterans included two aposematic species of the family Cercopidae (Ocoaxo sp. and Sphenorhina sp.), two cryptic species of the family Cixiidae (both Bothriocera spp.), and two structurally defended species of the family Membracidae (Camfylocentrus sp. and Vestistilus variabilis). We measured the distance at which models of Myioborus Redstarts elicited escape behavior in insects under field conditions. Response distances varied significantly with both homopteran primary defense and Myioborus plumage pattern. Structurally defended homopterans were the most sensitive to the models and cryptic homopterans were the least sensitive. The model simulating the plumage of endemic M. miniatus comptus of Costa Rica elicited greater responses than did models of other Myioborus taxa with either less or more white in the plumage. Our results suggest that (1) primary defense strategies can have a significant effect on insect vulnerability to flush-pursuit predators, and (2) geographic variation in the plumage pattern of Myioborus Redstarts may reflect adaptation to regional prey and habitat characteristics that maximizes flush-pursuit foraging performance. RESUMEN Las defensas de los insectos contra aves depredadoras, frecuentemente incluye dos tipos de defensa: una primaria, que disminuye la probabilidad de ser atacado, y una defensa secundaria tipica de comportamiento de escape, la cual es empleada si falla la defensa primaria. Sin embargo, el comportamiento de escape puede ocasionar que los insectos scan potencialmente vulnerables a depredadores especializados en vuelo y persecusión. Los colirrojos neotropicales del género Myioborus (Parulidae) explotan el comportamiento de escape de los insectos usando su plumaje contrastante bianco-negro, y su comportamiento de forrajeo animado para sobresaltar a los insectos a cazar, que luego son perseguidos y capturados en vuelo. Nosotros examinamos cómo la defensa primaria de insectos y la variación natural del plumaje en Myioborus influye en el comportamiento de escape en seis especies de homópteros de Monteverde, Costa Rica. Los seis homópteros estudiados incluyeron dos especies conspicuas de la familia Cercopidae (Ocoaxo esp. y Sphenorhina esp.), dos especies enigmáticas de la familia Cixiidae (ambos Bothriocera esp.), y dos especies de la familia Membracidae (Campylocentrus esp. y Vestistilus variabilis) que se defienden estructuralmente. Nosotros medimos la distancia en la cual los modelos colirrojos de Myioborus provocan el comportamiento de escape en insectos bajo de condiciones de campo. Las respuestas a las distancias variaron significativamente en ambas, en defensa primaria de los homópteros y el partón del plumaje de los Myioborus. Los homópteros que se defienden estructuralmente fueron los más vulnerables a los modelos, y los homópteros enigmáticos los menos vulnerables. El modelo simulando el plumaje del colirrojo M. miniatus comptus endémico de Costa Rica, produjo mayor respuesta que los otros modelos Myioborus de otras taxas con menos o más color bianco en su plumaje. Los resultados de este estudio sugieren que: (1) las defensas de estrategia primaria pueden tener un efecto significative en la vulnerabilidad de los insectos a los depredadores que vuelan y persiguen; y (2) la variación geografica en el partón del plumaje de los Myioborus colirrojos puede indicar adaptaciones a presas por regiones y a caracteristicas del hábitat que maximizan su habilidad de volar y perseguir. [source]

RECONSTRUCTING PLUMAGE EVOLUTION IN ORIOLES (ICTERUS): REPEATED CONVERGENCE AND REVERSAL IN PATTERNS

EVOLUTION, Issue 6 2000
Kevin E. Omland
Abstract. Several empirical studies suggest that sexually selected characters, including bird plumage, may evolve rapidly and show high levels of convergence and other forms of homoplasy. However, the processes that might generate such convergence have not been explored theoretically. Furthermore, no studies have rigorously addressed this issue using a robust phylogeny and a large number of signal characters. We scored the appearance of 44 adult male plumage characters that varied across New World orioles (Icterus). We mapped the plumage characters onto a molecular phylogeny based on two mitochondrial genes. Reconstructing the evolution of these characters revealed evidence of convergence or reversal in 42 of the 44 plumage characters. No plumage character states are restricted to any groups of species higher than superspecies in the oriole phylogeny. The high frequency of convergence and reversal is reflected in the low overall retention index (RI = 0.66) and the low overall consistency index (CI = 0.28). We found similar results when we mapped plumage changes onto a total evidence tree. Our findings reveal that plumage patterns and colors are highly labile between species of orioles, but highly conserved within the oriole genus. Furthermore, there are at least two overall plumage types that have convergently evolved repeatedly in the three oriole clades. This overall convergence leads to significant conflict between the molecular and plumage data. It is not clear what evolutionary processes lead to this homoplasy in individual characters or convergence in overall pattern. However, evolutionary constraints such as developmental limitations and genetic correlations between characters are likely to play a role. Our results are consistent with the belief that avian plumage and other sexually selected characters may evolve rapidly and may exhibit high homoplasy. The overall convergence in oriole plumage patterns is an interesting evolutionary phenomenon, but it cautions against heavy reliance on plumage characters for constructing phylogenies. [source]