Repeated divergent selection on pigmentation genes in a rapid finch radiation

Instances of recent and rapid speciation are suitable for associating phenotypes with their causal genotypes, especially if gene flow homogenizes areas of the genome that are not under divergent selection. We study a rapid radiation of nine sympatric bird species known as capuchino seedeaters, which are differentiated in sexually selected characters of male plumage and song. We sequenced the genomes of a phenotypically diverse set of species to search for differentiated genomic regions. Capuchinos show differences in a small proportion of their genomes, yet selection has acted independently on the same targets in different members of this radiation. Many divergent regions contain genes involved in the melanogenesis pathway, with the strongest signal originating from putative regulatory regions. Selection has acted on these same genomic regions in different lineages, likely shaping the evolution of cis-regulatory elements, which control how more conserved genes are expressed and thereby generate diversity in classically sexually selected traits.Fil: Campagna, Leonardo. Cornell University; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Repenning, Márcio. Pontificia Universidade Católica do Rio Grande do Sul. Museu de Ciências e Tecnologia; BrasilFil: Silveira, Luís Fábio. Universidade de Sao Paulo; BrasilFil: Fontana, Carla Suertegaray. Pontificia Universidade Católica do Rio Grande do Sul; BrasilFil: Tubaro, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Lovette, Irby. Cornell University; Estados Unido

Sistemática de Sporophila Hypoxantha: I: variación geográfica, ecología y evolución de las vocalizaciones

Geographically isolated populations diverging in vocalizations and habitat use are prime candidates for diversification along the speciation/differentiation continuum. The Tawny-bellied Seedeater (Sporophila hypoxantha) is relatively widespread, thus potentially variable across its range. We investigated geographic variation in vocalizations, habitat use, and migratory behavior, identifying five regiolects (song variants encompassing extensive subpopulations of a species and all individuals within this large range), which correspond with different patterns of habitat use but arose independently of migratory behavior. Given the low level of genetic divergence in the capuchinos, a subset of the genus Sporophila that includes S. hypoxantha, the phylogenetic potential for learning in the genus, the fast temporal changes evident within regiolects (chronolects), the existence of environmental sound assimilation, and the singing of subsongs by young males, we conclude that geographic variation is due mostly to learning, the genetic makeup of the various populations having little effect. The occurrence of allopatric habitat-related regiolects with little (if any) morphological differentiation, suggests that this constitutes a plausible step toward the evolution of new species in the capuchinos. These results highlight the importance of habitat use and vocalizations in understanding the evolutionary differentiation and diversification of the seedeaters and suggest that their explosive radiation has been strongly influenced by the interplay of habitat choice, migratory behavior, and vocal differentiation.Las poblaciones que se encuentran aisladas y que exhiben variación en sus vocalizaciones y en el uso del hábitat son candidatas a diversificación a lo largo del continuum especiación/diferenciación. Sporophila hypoxantha es una especie con una distribución relativamente amplia, y por eso probablemente exhiba variación geográfica. Investigamos la variación geográfica en sus vocalizaciones, uso de hábitat y comportamiento migratorio. Reconocimos cinco regiolectos (variantes de canto encontradas en subpoblaciones de una especie en una gran extensión y en todos los individuos dentro de este gran rango), que se corresponden con diferentes patrones de uso de hábitat, pero que aparecieron independientemente de la presencia del comportamiento migratorio. Dada la escasa divergencia genética entre los capuchinos, un grupo dentro del género Sporophila que incluye a S. hypoxantha, el potencial filogenético para el aprendizaje en el género, los cambios rápidos dentro de regiolectos (cronolectos), la existencia de asimilación acústica ambiental y la grabación de machos jóvenes con sub-cantos, concluimos que la variación geográfica se debe principalmente al aprendizaje, con poco efecto del trasfondo genético de las diferentes poblaciones. La presencia de regiolectos alopátricos vinculados a hábitats, con poca (o ninguna) diferenciación morfológica, sugiere que esto constituye una etapa hacia la evolución de nuevas especies en los capuchinos. Este trabajo resalta la importancia del uso de hábitat y de las vocalizaciones para entender la diferenciación evolutiva y la diversificación en Sporophila, y sugiere que su radiación explosiva ha sido fuertemente influenciada por la interacción entre los procesos de selección de hábitat, comportamiento migratorio y diferenciación vocal.Fil: Areta, Juan Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción; Argentina; ArgentinaFil: Repenning, Márcio. Pontificia Universidade Catolica Do Rio Grande Do Sul; Brasi

Sistemática de Sporophila Hypoxantha: II: taxonomía e implicancias evolutivas de la existencia de una nueva forma en Sporophila

The capuchinos, a subset of the genus Sporophila, represent a radiation of seedeaters characterized by little genetic differentiation, virtually no change in bill and body shape, marked plumage differences on a common theme, and notable differentiation in vocalizations and habitat use. We describe a distinctive variant that would have been considered a species by the traditional strictly phenotypical criteria for classification of species in the genus. This variant resembles the Tawny-bellied Seedeater (S. hypoxantha) but has a tawny, not gray, nape and back. It is also identical in pattern to the Chestnut Seedeater (S. cinnamomea) but has a tawny rather than chestnut body. We tested four hypotheses to assess the status of the variant: that it represents a new species, a hybrid S. hypoxantha × S. cinnamomea, a color morph of S. cinnamomea, or a color morph of S. hypoxantha. The variant is identical to S. hypoxantha in vocalizations and habitat use, varying geographically in parallel. Both forms breed syntopically, and the tawny variant is recorded only within the range of S. hypoxantha, with many records from areas where S. hypoxantha is the only breeding representative of the ruficollis group. We consider the tawny variant to be a color morph of S. hypoxantha. Two nontrivial evolutionary paths can constitute precursors to speciation in the capuchinos: (1) differentiation in vocalizations and habitat use arises with little plumage change in more or less geographically isolated populations, and (2) differentiation in plumage proceeds without change in vocalizations and habitat use within some populations.Los capuchinos representan un conjunto de especies del genero Sporophila proveniente de una radiación única de pequeños semilleritos-fruteros. Esta radiación ha ocurrido con escasa diferenciación genética, virtualmente sin cambios en las formas del pico y cuerpo, marcadas diferencias en el plumaje sobre una base común y diferencias notables en sus vocalizaciones y uso de hábitat. Describimos una variante distintiva que hubiera sido considerada una especie con base en el criterio tradicional estrictamente fenotípico de asignación de especies en el género. Esta forma es similar a S. hypoxantha, pero con la nuca y la espalda naranjas en vez de gris. También tiene un patrón idéntico a S. cinnamomea, pero con cuerpo naranja en vez de castaño. Pusimos a prueba cuatro hipótesis sistemáticas para evaluar el status de esta variante: que representa una nueva especie, un híbrido S. hypoxantha x S. cinnamomea, un morfo de color de S. cinnamomea o un morfo de color de S. hypoxantha. La nueva variante es idéntica a S. hypoxantha en vocalizaciones y uso de hábitat, mostrando la misma variación geográfica en estas características. Ambas formas crían en sintopía y todos los registros de la nueva variante se presentaron dentro de los límites geográficos de S. hypoxantha, con varios registros en áreas dónde S. hypoxantha es el único representante del grupo ruficollis que cría. Consideramos que la nueva variante es un morfo de color de S. hypoxantha. Dos trayectorias evolutivas no triviales pueden constituir precursores a la especiación en los capuchinos: (1) la diferenciación en vocalizaciones y uso de hábitat aparecen con escaso cambio en el plumaje en poblaciones más o menos aisladas geográficamente y (2) la marcada diferenciación en el plumaje aparece sin cambios en las vocalizaciones y en el uso de hábitat dentro de algunas poblaciones.Fil: Areta, Juan Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción; Argentina; ArgentinaFil: Repenning, Márcio. Pontificia Universidade Catolica Do Rio Grande Do Sul; Brasi

Breeding habitats, phenology and size of a resident population of Two-banded Plover (Charadrius falklandicus) at the northern edge of its distribution

The central-peripheral hypothesis states that the demographic performance of a species decreases from the centre to the edge of its range. Peripheral populations are often smaller and tend to occur under different and suboptimal conditions from those of core populations. Peripheral populations can also coexist during part of their annual cycle with populations from the core of the species’ range. Studies on peripheral populations are thus valuable for broadly understanding ecological and evolutionary processes. The Two-banded Plover (TWBP, Charadrius falklandicus, Charadriidae) is an endemic South American shorebird that breeds in Argentine and Chilean Patagonia and migrates northward during the Austral winter. There are breeding records, however, from Lagoa do Peixe National Park in southern Brazil. In this study, we (i) mapped TWBP nests, (ii) characterised their reproductive biology and nesting habitats, (iii) colour-marked birds and evaluated their seasonal occurrence patterns and (iv) estimated the size of the Brazilian population by combining supervised habitat classification analyses and generalised additive models. We estimated that the Brazilian population has 55 (95% CI: 44.1–66.6) breeding pairs and found that the length of their breeding season was roughly 5 months, spanning the Austral spring and summer. The population’s nesting habitat differed, and their apparent reproductive success was lower than that of core populations. Unlike more southerly populations, the results of our markresighting efforts demonstrate that the Brazilian population is sedentary. Taken together, these results indicate that the Brazilian TWBP population seems geographically isolated from the species’ southernmost core populations, resulting in a heteropatric distribution. Furthermore, differences in nesting habitat and year-round residency indicate that this peripheral population is ecologically distinct. The marked behavioural and ecological differences combined with the small population at the northern edge of the TWBP distribution support the central-peripheral hypothesis in a Neotropical system

Rediscovery of the hummingbird Heliodoxa rubricauda (Boddaert, 1783) (Aves: Trochilidae) in Rio Grande do Sul, southern Brazil

We report the rediscovery of the hummingbird Heliodoxa rubricauda (Boddaert, 1783) in the Brazilian state of Rio Grande do Sul after nearly 130 years without confirmed records. We captured 3 males and 1 female, and found 2 other birds (including an immature) at 3 sites in the municipalities of São Francisco de Paula and Cambará do Sul, in the northeast of the state. All records were at the top of the Southern Brazilian Plateau escarpment, at altitudes of about 900 m and near the southern limit of the Atlantic Forest

Análise comparativa da dieta de quatro espécies de cucos (Aves: Cuculidae), no sul do Brasil

We studied stomachs contents of 50 specimens of four common cuckoo species (Cuculidae) from southern Brazil: Guira guira (Gmelin, 1788) (n = 21), Coccyzus melacoryphus (Vieillot, 1817) (n = 8), Crotophaga ani (Linnaeus, 1758) (n = 11), and Piaya cayana (Linnaeus, 1766) (n = 10). We measured stomach volume and prey were identified and quantified based in their dimensions. The size of the prey was associated with bill width and body mass. Diet items were analyzed and identified to the lowest possible taxonomic level, based on literature, scientific collection data, and specialists. The diet of the four species was composed by 100% animal species, with invertebrate dominance. Only in G. guira stomachs the presence of vertebrates was observed more than once (amphibian, reptile, and bird). C. ani, which had similar diet, ingested a large number of Arachnida and Orthoptera. Piaya cayana ate mostly Hemiptera. The predominance of caterpillars (Lepidoptera), suggested in the literature was not observed in the diet of C. melacoryphus. There was a statistically significant difference in bill width and body mass among the bird species, and there was no correlation between bill width and the proportion of medium and large-sized prey