RESUMEN
The floral phenotype plays a main role in the attraction and fit of pollinators. Both perianth traits and the positioning of sex organs can be subjected to natural selection and determine nonrandom mating patterns in populations. In stylar-polymorphic species, the Darwinian hypothesis predicts increased mating success between individuals with sex organs at equivalent heights (i.e. with higher reciprocity). We used paternity analyses in experimental populations of a stylar-dimorphic species. By comparing the observed mating patterns with those expected under random mating, we tested the effects of sex organ reciprocity and perianth traits on mating success. We also analysed phenotypic selection on perianth traits through female and male functions. The (dis)similarity of parental perianth traits had no direct effects on the mating patterns. Sex organ reciprocity had a positive effect on mating success. Narrow floral tubes increased this effect in upper sex organs. Perianth traits showed little signs of phenotypic selection. Female and absolute fitness measures resulted in different patterns of phenotypic selection. We provide precise empirical evidence of the Darwinian hypothesis about the functioning of stylar polymorphisms, demonstrating that mating patterns are determined by sex organ reciprocity and only those perianth traits which are critical to pollinator fit.
Asunto(s)
Flores , Polinización , Evolución Biológica , Flores/genética , Reproducción/genética , Selección GenéticaRESUMEN
BACKGROUND: Estimating outcrossing/selfing rates and characterizing genetic diversity with microsatellite markers are crucial to understanding the evolution of plant mating systems. METHODS AND RESULTS: We developed, optimized and characterized eight new primer pairs for Centaurium grandiflorum ssp. boissieri and transferred them to three subspecies of Centaurium quadrifolium. Two SSR loci were transferred from Sabatia campestris to the four Centaurium taxa. Polymorphisms, He, Ho and H-W deviations were estimated in two populations of C. grandiflorum ssp. boissieri and in seven individuals each of C. quadrifolium ssp. barrelieri, C. quadrifolium ssp. parviflorum and C. quadrifolium ssp. quadrifolium. A total of 80 individuals was used in these experiments. The number of polymorphic loci varied among species from one to ten. A total of 127 alleles was scored. The average number of alleles per locus was 12.7. He was higher than Ho in all sampled populations. Hardy-Weinberg equilibrium was found for some loci in different species. CONCLUSIONS: This is the first report of microsatellites successfully amplified in the whole Centaurium genus. They will be valuable for estimating mating system parameters and genetic diversity and exploring their relationships with the wide variation in flower morphology in the genus, especially anther-stigma separation.
Asunto(s)
Centaurium/genética , Repeticiones de Microsatélite/genética , Alelos , Flores/genética , Sitios Genéticos , Variación Genética , Hibridación Genética , Polimorfismo GenéticoRESUMEN
Este artículo tiene como propósito analizar la expansión de la influencia de China en América Latina en los ámbitos económico y militar y la forma como Estados Unidos ha reaccionado a esta. Para ello se recurrirá a la metodología del estudio de caso -Venezuela, Bolivia y Ecuador-, ya que es allí donde China cuenta con una fuerte presencia y sobre todo porque son países que, al igual que la potencia asiática, tienen una política anti-estadounidense o soberanista que busca consolidar un orden mundial multipolar El principal hallazgo es que China no representa una amenaza seria para Estados Unidos en el corto plazo, y que de hecho, la expansión de su influencia en la región ha sido percibida por el gobierno de Estados Unidos como una oportunidad. Ello se debe a varias razones: China ha implementado una política cautelosa y pragmática que busca consolidar sus objetivos nacionales sin desafiar directamente la hegemonía estadounidense en la región, actitud reforzada por limitaciones internas que llevan al liderazgo chino a optar por una actitud menos activista en la reorganización político-militar del mundo. Por otro lado, gracias a que Estados Unidos, que se encuentra en una fase de declive de su hegemonía en la región, prefiere promover sus intereses en un marco cooperativo y no conflictivo, esperando sacar provecho de esta nueva situación.
This article seeks to analyze the expansion of China's influence in Latin America in economic and military fields, and how the United States has reacted to it. For it will be used the methodology of the case study -Venezuela, Bolivia and Ecuador-, since it is where China has a strong presence and especially because they are countries, like the Asian power have an anti-American or sovereignist politics which seeks to consolidate a multipolar world order The main finding is that China does not pose a serious threat to the United States in the short term, and in fact expanding its influence in the region has been perceived by the United State government as an opportunity. This is due to several reasons: China has implemented a cautious and pragmatic policy that seeks to consolidate its national goals without directly challenging American hegemony in the region, reinforced by internal constraints that lead the Chínese leadership to opt for a less activist attitude in the military-political reorganization of the world. On the other hand, due to the United States, which is in a phase of decline of its hegemony in the region, prefer to promote their interests in a cooperative and non-confrontational framework, hoping to take advantage of this new situation.
Este artigo tem por objetivo analisar a expansão da influência da China na América Latina nos campos econômico e militar, bem como os Estados Unidos reagiu a este. Pois será utilizada a metodologia do estudo de caso-Venezuela, Bolívia e Equador, já que é onde a China tem uma forte presença e, especialmente, porque são países, como a potência asiática, têm um anti-política americano ou soberanista que busca consolidar uma ordem mundial multipolar. A principal constatação é que a China não representa uma séria ameaça para os EUA no curto prazo, e de fato, a expansão da sua influência na região tem sido percebida pelo governo dos EUA como uma oportunidade. Isto é devido a várias razões: China tem implementado uma política cautelosa e pragmática que visa consolidar as suas metas nacionais sem desafiar diretamente a hegemonia dos EUA na região, reforçada por restrições internas que levam a liderança chinesa a optar por uma atitude menos ativista na atitude reorganização político-militar do mundo. Por outro lado, graças aos Estados Unidos, que está em uma fase de declínio de sua hegemonia na região, preferem promover os seus interesses em um quadro de cooperação e não de confronto, na esperança de tirar proveito desta nova situação.
