Covariation Of Song, Morphological, And Allozyme Frequency Characters In The Rufous-collared Sparrow, Zonotrichia Capensis

In the Rufous-collared Sparrow (Zonotrichia capensis) song dialects, defined by rate of delivery of the terminal trill, are clearly associated with variation in vegetation. The local adaptation hypothesis suggests that these dialects may act as markers for different populations adapted to different local environmental conditions predicting that there will be a correlation between the patterns of vocal and genetic variation. Thus, covariation of allozyme frequencies, and morphological (external and skeletal) measures and song characters was investigated in northwestern Argentine populations of Rufous-collared Sparrows with particular reference to possible correlations between vocal dialects and population structure. Approximately 20 males were collected from each of four sites within each of six different vegetations (and thus, six vocal dialects): lowland chaco thornscrub, transition forest, montane woodland, montane grassland, Monte desert scrub, and puna high altitude scrub.;There was significant variability in both external and skeletal morphology among all 24 sites and among vegetation/dialect populations. Overall Wright\u27s corrected inbreeding coefficient (F{dollar}\sb{lcub}\rm ST{rcub}{dollar}) was 0.119 indicating significant genetic differentiation among sites within the study area. Hierarchical Wright\u27s F statistics indicated that only 50% of among site variability was due to a vegetation/dialect effect.;Puna scrub sites were differentiated from all other sites with respect to both morphology and allozyme frequencies. Heterogeneity at the PGM-1 locus among puna scrub sites was the major cause of the high F{dollar}\sb{lcub}\rm ST{rcub}{dollar} value overall and within puna scrub vegetation (F{dollar}\sb{lcub}\rm ST{rcub}{dollar} = 0.156). Puna scrub populations have traditionally been treated as a subspecies (pulacayensis) separate from other populations within the study area (hypoleuca) and my data support this contention.;Genetic differentiation overall among all non-puna sites (corrected F{dollar}\sb{lcub}\rm ST{rcub}{dollar} = 0.018) was similar to differentiation among sites within each of the five non-puna vegetations (average corrected F{dollar}\sb{lcub}\rm ST{rcub}{dollar} = 0.0132 {dollar}\pm{dollar} 0.0069). Hierarchical Wright\u27s F statistics indicated that none of the among site differentiation in this subset of samples was due to a vegetation/dialect effect. These observations are not consistent with the local adaptation hypothesis.;Overall covariation between morphology and allozyme frequencies was evident in that puna scrub populations were distinct from all other sampled populations. Mantel\u27s non-parametric tests based on non-puna sites indicated that there was no covariation between morphological Mahalanobis and Rogers\u27 genetic distance matrices. Degree of morphological differentiation was associated with both geographic distance and differences between habitats. There was no significant covariation between genetic distance and geographic distance suggesting no simple isolation-by-distance effect. Finally, there was no relationship between song Mahalanobis distances (based on frequency and temporal characters of song) and either morphology or habitat structure.;All significant genetic heterogeneity occurred among sites in mountainous habitats and I conclude that topography and patchiness of habitat were probably major factors involved in population differentiation, rather than vocal dialects

La geometría de visualización afecta el dicromatismo sexual y la conspicuidad de la coloración del plumaje no iridiscente de Tersina viridis

Some types of plumage color are difficult to characterize spectrophotometrically because the properties of the reflected light change with viewing geometry (i.e. the relative positions of the light source and the observer, and the orientation of the feather). This is the case for the noniridescent plumage coloration of the Swallow Tanager (Tersina viridis), which seems to change from a human perspective as the angle between the light source and the observer varies. In this study, we measured plumage reflectance with different angles of illumination and/or observation, and used avian visual models to evaluate the change in sexual dichromatism and conspicuousness with viewing geometry from a bird’s perspective. We also calculated different color parameters to assess how these changed with viewing conditions. Sexual dichromatism showed large changes, with its maximum coinciding with the angle combination between illuminant and observer that produced both the highest conspicuousness for males and the highest crypsis for females. The conspicuousness of males also varied with viewing geometry, and was consistently less when viewed by the visual system of a potential avian predator (VS) than by that of a conspecific (UVS). The change in perceived coloration was mainly related to large variation in hue and chroma in the plumage of males as the relative angle between the illumination and observation probes changed. Our results show that viewing geometry can alter color perception, even for noniridescent plumage coloration. Therefore, the relative position of the light source and the observer should be considered in studies of avian visual communication, particularly for species with plumage coloration similar to that of Swallow Tanagers.Algunos tipos de colores del plumaje son difíciles de caracterizar espectrofotometricamente debido a que las propiedades de la luz que reflejada varían con la geometría de visualización (es decir, la posición relativa de la fuente lumínica, el observador y la pluma). Este es el caso de la coloración no-iridiscente de la Tersina viridis, que parece cambiar desde la perspectiva humana al modificarse el ángulo conformado entre el observador y la fuente de luz. En este trabajo medimos la reflectancia del plumaje con diferentes ángulos de iluminación y/o observación y empleamos modelos visuales avianos para evaluar el cambio en dicromatismo sexual y conspicuidad. Tambien calculamos parámetros descriptores de la coloración para determinar cómo cambian estos en función de la geometría de visualización. El dicromatismo sexual mostró una amplia variación, siendo máximo con la combinación de ángulos entre iluminante y observador que también produjo el máximo de conspicuidad en los machos y el máximo de cripsis en las hembras. La conspicuidad de los machos tambien varió con la geometría de visualización y además fue consistentemente menor para sistemas visuales avianos menos sensibles al UV (como los de los máximos potenciales predadores de esta especie) que para sus conspecíficos, que serían más sensibles a longitudes de onda del UV. El cambio percibido en la coloración estuvo principalmente relacionado a una gran variación en el tono y la saturación en el plumaje de los machos al cambiar el ángulo conformado entre la fuente lumínica y el observador. Nuestros resultados muestran que la geometría de visualización puede alterar la percepción del color, a un en plumajes no-iridiscentes. Por lo tanto, es importante considerar la posición relativa de la fuente de luz y el observador en estudios de comunicación visual en aves, particularmente en especies con coloración del plumaje como la de la Tersina viridis.Fil: Barreira, Ana Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: García, Natalia Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Lougheed, Stephen C.. Queens University, Department Of Biology; CanadáFil: Tubaro, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin

Cryptic diversity and deep divergence in an upper Amazonian leaflitter frog, Eleutherodactylus ockendeni

Supplementary files available: Additional file 1: Specimen information. Museum catalogue numbers (QCAZ) for E. ockendeni and two outgroup species, GenBank accession numbers for cyt b and/or 16S fragment, and locality of origin for each individual used in the study.- Additional file 2: TN-corrected p-distance among cyt b haplotypes. TN-corrected p-distances among cyt b haplotypes of E. ockendeni, grouped by clade.[Background] The forests of the upper Amazon basin harbour some of the world's highest anuran species richness, but to date we have only the sparsest understanding of the distribution of genetic diversity within and among species in this region. To quantify region-wide genealogical patterns and to test for the presence of deep intraspecific divergences that have been documented in some other neotropical anurans, we developed a molecular phylogeny of the wide-spread terrestrial leaflitter frog Eleutherodactylus ockendeni (Leptodactylidae) from 13 localities throughout its range in Ecuador using data from two mitochondrial genes (16S and cyt b; 1246 base pairs). We examined the relation between divergence of mtDNA and the nuclear genome, as sampled by five speciesspecific microsatellite loci, to evaluate indirectly whether lineages are reproductively isolated where they co-occur. Our extensive phylogeographic survey thus assesses the spatial distribution of E. ockendeni genetic diversity across eastern Ecuador.[Results] We identified three distinct and well-supported clades within the Ecuadorean range of E. ockendeni: an uplands clade spanning north to south, a northeastern and central lowlands clade, and a central and southeastern clade, which is basal. Clades are separated by 12% to 15% net corrected p-distance for cytochrome b, with comparatively low sequence divergence within clades. Clades marginally overlap in some geographic areas (e.g., Napo River basin) but are reproductively isolated, evidenced by diagnostic differences in microsatellite PCR amplification profiles or DNA repeat number and coalescent analyses (in MDIV) best modelled without migration. Using Bayesian (BEAST) and net phylogenetic estimates, the Southeastern Clade diverged from the Upland/ Lowland clades in the mid-Miocene or late Oligocene. Lowland and Upland clades speciated more recently, in the early or late Miocene.[Conclusion] Our findings uncover previously unsuspected cryptic species diversity within the common leaflitter frog E. ockendeni, with at least three different species in Ecuador. While these clades are clearly geographically circumscribed, they do not coincide with any existing landscape barriers. Divergences are ancient, from the Miocene, before the most dramatic mountain building in the Ecuadorean Andes. Therefore, this diversity is not a product of Pleistocene refuges. Our research coupled with other studies suggests that species richness in the upper Amazon is drastically underestimated by current inventories based on morphospecies.Peer reviewe

Continental phylogeography of an ecologically and morphologically diverse Neotropical songbird, Zonotrichia capensis

[Background]: The Neotropics are exceptionally diverse, containing roughly one third of all extant bird species on Earth. This remarkable species richness is thought to be a consequence of processes associated with both Andean orogenesis throughout the Tertiary, and climatic fluctuations during the Quaternary. Phylogeographic studies allow insights into how such events might have influenced evolutionary trajectories of species and ultimately contribute to a better understanding of speciation. Studies on continentally distributed species are of particular interest because different populations of such taxa may show genetic signatures of events that impacted the continent-wide biota. Here we evaluate the genealogical history of one of the world's most broadly-distributed and polytypic passerines, the rufous-collared sparrow (Zonotrichia capensis). [Results]: We obtained control region DNA sequences from 92 Zonotrichia capensis individuals sampled across the species' range (Central and South America). Six additional molecular markers, both nuclear and mitochondrial, were sequenced for a subset of individuals with divergent control region haplotypes. Median-joining network analysis, and Bayesian and maximum parsimony phylogenetic analyses all recovered three lineages: one spanning Middle America, the Dominican Republic, and north-western South America; one encompassing the Dominican Republic, Roraima (Venezuela) and La Paz (Bolivia) south to Tierra del Fuego, Argentina; and a third, including eastern Argentina and Brazil. Phylogenetic analyses suggest that the Middle American/north-western South American clade is sister to the remaining two. Bayesian and maximum likelihood coalescent simulations used to study lineage demographic history, diversification times, migration rates and population expansion together suggested that diversification of the three lineages occurred rapidly during the Pleistocene, with negligible gene flow, leaving genetic signatures of population expansions. [Conclusions]: The Pleistocene history of the rufous-collared sparrow involved extensive range expansion from a probable Central American origin. Its remarkable morphological and behavioral diversity probably represents recent responses to local conditions overlying deeper patterns of lineage diversity, which are themselves produced by isolation and the history of colonization of South America.Funding was provided by NSERC Discovery grants to Lougheed and Handford, by CONICET, ANPCyT and IDRC, and by a National Geographic Society Research Grant to Chris Moyes.Peer Reviewe

Diferencias de Coloracio´n entre Especies Cercanamente Emparentadas de Pechos Colorados (Sturnella)

Interspecific differences in sexually selected traits may be important for maintaining reproductive isolation among closely related species living in sympatry. We present the first study of plumage color differences among males of partially sympatric species of South American red-breasted meadowlarks (the Long-tailed Meadowlark, the Pampas Meadowlark and the White-browed Blackbird, Sturnella loyca, S. defilippii and S. superciliaris, respectively) using reflectance spectrophotometry and the avian visual model of Vorobyev and Osorio (1998). Reflectance values of sexually dichromatic red plumage patches were measured on study skins. Total reflectance, reflectance in the short wavelength part of the spectrum and several measures of spectral shape were extracted directly from the spectra data. These variables were subjected to two-way ANCOVAs, with species and season (breeding/non-breeding) as main factors and year of capture as a covariate. These analysis revealed that S. loyca and S. defilippii were brighter and had a higher reflectance in the short wavelength part of the spectrum than S. superciliaris. The wavelength of minimum reflectance showed higher values in breeding plumage versus non-breeding. Interspecific distances in avian visual space were considerably higher than the threshold value for color discrimination, denoting that the differences found are also detectable by birds. Taken together, these results showed that the red plumage patches of these three species present significant color differences throughout the year not only in the visible but also in the UV part of the spectrum.Las diferencias interespecíficas en caracteres sexualmente seleccionados pueden ser importantes para mantener el aislamiento reproductivo entre especies simpátricas cercanamente emparentadas. Este es el primer estudio de las diferencias de coloración de plumaje entre machos de especies parcialmente simpátricas de pechos colorados sudamericanos (Sturnella superciliaris, S. defilippii,yS. loyca) usando espectrofotometría de reflectancia y el modelo de percepción visual de Vorobyev y Osorio (1998). Los valores de reflectancia de los parches rojos sexualmente dimórficos fueron medidos en pieles de estudio. La reflectancia total, la reflectancia en la porción de onda corta del espectro y varias medidas de forma espectral fueron obtenidas directamente de los espectros. Nuestros análisis revelaron que S. loyca y S. defilippii fueron más brillantes y tuvieron mayor reflectancia en la regio´n de onda corta del espectro que S. superciliaris. La posición de reflectancia mínima se localizó a longitudes de onda mayores en el plumaje reproductivo comparado con el no reproductivo. Las distancias interespecíficas en el espacio visual aviano obtenidas del modelo de Vorobyev y Osorio (1998) fueron considerablemente mayores que el valor umbral de discriminación de color, indicando que estas diferencias son también detectables por las aves. Tomados en su conjunto, estos resultados muestran que los parches de plumaje rojo de estas tres especies presentan diferencias significativas en la coloración durante todo el año tanto en la porción visible del espectro como en la UVFil: Benites, Maria del Pilar. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Tubaro, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina. University of Kansas; Estados UnidosFil: Lijtmaer, Dario Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Lougheed, Stephen C.. Queens University. Department Of Biology; CanadáFil: Eaton, Muir D.. University of Kansas; Estados Unido

Continental phylogeography of an ecologically and morphologically diverse neotropical songbird, Zonotrichia capensis

The Neotropics are exceptionally diverse, containing roughly one third of all extant bird species on Earth. This remarkable species richness is thought to be a consequence of processes associated with both Andean orogenesis throughout the Tertiary, and climatic fluctuations during the Quaternary. Phylogeographic studies allow insights into how such events might have influenced evolutionary trajectories of species and ultimately contribute to a better understanding of speciation. Studies on continentally distributed species are of particular interest because different populations of such taxa may show genetic signatures of events that impacted the continentwide biota. Here we evaluate the genealogical history of one of the world’s most broadly-distributed and polytypic passerines, the rufous-collared sparrow (Zonotrichia capensis).Fil: Lougheed, Stephen C.. Queen’s University. Department of Biology; Canadá;Fil: Campagna, Leonardo. Cornell University; Estados Unidos de América; Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales. División de Ornitología; Argentina;Fil: Dávila, José A.. Instituto de Investigación en Recursos Cinegéticos; España;Fil: Tubaro, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales. División de Ornitología; Argentina;Fil: Lijtmaer, Dario Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales. División de Ornitología; Argentina;Fil: Handford, Paul. University of Western Ontario. Department of Biology; Canadá

Hierarchies of evolutionary radiation in the world’s most species rich vertebrate group, the Neotropical Pristimantis leaf litter frogs

The Neotropical leaf litter frog genus Pristimantis is very species-rich, with 526 species described to date, but the full extent of its diversity is much higher and remains unknown. This study explores the phylogenetic processes and resulting evolutionary patterns of diversification in Pristimantis. Given the well-recognised failure of morphology- and community-based species groups to describe diversity within the genus, we apply a new test for the presence and phylogenetic distribution of higher evolutionary units. We developed a phylogeny based on 260 individuals encompassing 149 Pristimantis presumed species, sampled at mitochondrial and nuclear genes (3718 base pair alignment), combining new and available sequence data. Our phylogeny broadly agrees with previous studies, both in topology and age estimates, with the origin of Pristimantis at 28.97 (95% HDP =21.59 – 37.33) million years ago (MYA). New taxa that we add to the genus, which had not previously been included in Pristimantis phylogenies, suggest considerable diversity remains to be described. We assessed patterns of lineage origin and recovered 14 most likely (95% CI: 13–19) phylogenetic clusters or higher evolutionary significant units (hESUs) within Pristimantis. Diversification rates decrease towards the present following a density-dependent pattern for Pristimantis overall and for most hESU clusters, reflecting historical evolutionary radiation. The timing of diversification suggests that geological events in the Miocene, such as Andes orogenesis and Pebas system formation and drainage, may have had a direct or indirect impact on the evolution of Pristimantis and thus contributed to the origins of evolutionary independent phylogenetic clusters

Developing approaches for linear mixed modeling in landscape genetics through landscape-directed dispersal simulations

Dispersal can impact population dynamics and geographic variation, and thus, genetic approaches that can establish which landscape factors influence population connectivity have ecological and evolutionary importance. Mixed models that account for the error structure of pairwise datasets are increasingly used to compare models relating genetic differentiation to pairwise measures of landscape resistance. A model selection framework based on information criteria metrics or explained variance may help disentangle the ecological and landscape factors influencing genetic structure, yet there are currently no consensus for the best protocols. Here, we develop landscape-directed simulations and test a series of replicates that emulate independent empirical datasets of two species with different life history characteristics (greater sage-grouse; eastern foxsnake). We determined that in our simulated scenarios, AIC and BIC were the best model selection indices and that marginal R-2 values were biased toward more complex models. The model coefficients for landscape variables generally reflected the underlying dispersal model with confidence intervals that did not overlap with zero across the entire model set. When we controlled for geographic distance, variables not in the underlying dispersal models (i.e., nontrue) typically overlapped zero. Our study helps establish methods for using linear mixed models to identify the features underlying patterns of dispersal across a variety of landscapes.Endangered Species Recovery Fund (WWF, Environment Canada, Ontario Ministry of Natural Resources)US Bureau of Land ManagementUS Geological SurveyWyoming Game and Fish Departmen

Cryptic species and independent origins of allochronic populations within a seabird species complex (Hydrobates spp.)

Humans are inherently biased towards naming species based on morphological differences, which can lead to reproductively isolated species being mistakenly classified as one if they are morphologically similar. Recognising cryptic diversity is needed to understand drivers of speciation fully, and for accurate estimates of global biodiversity and assessments for conservation. We investigated cryptic species across the range of band-rumped storm-petrels (Hydrobates spp.): highly pelagic, nocturnal seabirds that breed on tropical and sub-tropical islands in the Atlantic and Pacific Oceans. In many breeding colonies, band-rumped storm-petrels have sympatric but temporally isolated (allochronic) populations; we sampled all breeding locations and allochronic populations. Using mitochondrial control region sequences from 754 birds, cytochrome b sequences from 69 birds, and reduced representation sequencing of the nuclear genomes of 133 birds, we uncovered high levels of genetic structuring. Population genomic analyses revealed up to seven unique clusters, and phylogenomic reconstruction showed that these represent seven monophyletic groups. We uncovered up to six independent breeding season switches across the phylogeny, spanning the continuum from genetically undifferentiated temporal populations to full allochronic species. Thus, band-rumped storm-petrels encompass multiple cryptic species, with non-geographic barriers potentially comprising strong barriers to gene flow