Examinando por Autor "Quirici, V."
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Ítem Avian haemosporidian and latitudinal gradients: Opportunities and challenges in the Southern Cone of America(Asociacion Espanola de Ecologia Terrestre, 2020) Cuevas, E.; Doussang, D.; Cevidanes, A.; Quirici, V.Latitudinal diversity gradients (LDG) explain the distribution and species richness in free-living organisms of multiple taxa, where richness increases toward low latitudes. However, parasites have shown inconsistencies to this spatial pattern. In the case of avian haemosporidians (Plasmodium, Haemoproteus and Leucocytozoon), they have shown differences depending of the genera and geographic scale. Thus, at global scale none of the three genera presents a latitudinal gradient of diversity. In South America, Plasmodium and Haemoproteus present a LDG, and the prevalence shows the same pattern in local Chile. In contrast, Leucocytozoon exhibits an inverse latitudinal pattern at the continental level and in Chile, where diversity and prevalence are associated with high latitudes. The climatic and habitat characteristics of the Amazon represents great influence to maintain the interactions of Plasmodium and Haemoproteus with their vectors and hosts but represent an environmental filter for Leucocytozoon. Despite the important role of vectors in the maintenance of LDG for avian haemosporidians, this approach has not been incorporated in any study in the region. Finally, biogeographic barriers, such as the Andes mountain range could interrupt the dispersal of lineages from the Amazon to other regions, like the Southern Cone of America. Thus, countries such as Chile and Argentina present extraordinary geographical characteristics to explore hypotheses associated with local dispersion and/or diversification processes.Ítem Evidence of low within-pair genetic relatedness in a relict population of Thorn-tailed Rayadito despite long-term isolation(John Wiley and Sons Ltd, 2022-03) Botero-Delgadillo, E.; Quirici, V.; Ippi, S.; Vásquez, R.; Kempenaers, B.Investigating whether mating patterns are biased in relation to kinship in isolated populations can provide a better understanding of the occurrence of inbreeding avoidance mechanisms in wild populations. Here, we report on the genetic relatedness (r) among breeding pairs in a relict population of Thorn-tailed Rayadito (Aphrastura spinicauda) in north-central Chile that has experienced a long-term history of isolation. We used simulations based on 8 years of data to assess whether mating is random with respect to relatedness. We found that mean and median population values of pair relatedness tended to be lower than randomly generated values, suggesting that mating is not random with respect to kinship. We hypothesize that female-biased dispersal is the main mechanism reducing the likelihood of mating among kin, and that the proportion of related pairs (i.e., r > 0.125) in the study population (25%) would presumably be higher in the absence of sex-biased dispersal. The occurrence of other mechanisms such as extra-pair copulations, delayed breeding, and active inbreeding avoidance through kin discrimination cannot be dismissed and require further study.Ítem The relationship of telomere length to baseline corticosterone levels in nestlings of an altricial passerine bird in natural populations(BIOMED CENTRAL, 2015-10) Quirici, V.; Guerrero, C.J.; Krause, J.S.; Wingfield, J.C.; Vásquez, R.A.Background: Environmental stressors increase the secretion of glucocorticoids that in turn can shorten telomeres via oxidative damage. Modification of telomere length, as a result of adversity faced early in life, can modify an individual's phenotype. Studies in captivity have suggested a relationship between glucocorticoids and telomere length in developing individuals, however less is known about that relationship in natural populations. Methods: In order to evaluate the effect of early environmental stressors on telomere length in natural populations, we compared baseline corticosterone (CORT) levels and telomere length in nestlings of the same age. We collected blood samples for hormone assay and telomere determination from two geographically distinct populations of the Thorn-tailed Rayadito (Aphrastura spinicauda) that differed in brood size; nestlings body mass and primary productivity. Within each population we used path analysis to evaluate the relationship between brood size, body mass, baseline CORT and telomere length. Results: Within each distinct population, path coefficients showed a positive relationship between brood size and baseline CORT and a strong and negative correlation between baseline CORT and telomere length. In general, nestlings that presented higher baseline CORT levels tended to present shorter telomeres. When comparing populations it was the low latitude population that presented higher levels of baseline CORT and shorter telomere length. Conclusions: Taken together our results reveal the importance of the condition experienced early in life in affecting telomere length, and the relevance of integrative studies carried out in natural conditions.Ítem The Subantarctic Rayadito (Aphrastura subantarctica), a new bird species on the southernmost islands of the Americas(Nature Research, 2022-08) Rozzi, R.; Quilodrán, C.; Botero-Delgadillo, E.; Napolitano, C.; Torres-Mura, J.; Barroso, O.; Crego, R.; Bravo, C.; Ippi, S.; Quirici, V.; Mackenzie, R.; Suazo, C.; l Rivero-de-Aguilar, J.; Goffinet, B.; Kempenaers, B.; Poulin, E.; Vásquez, R.We describe a new taxon of terrestrial bird of the genus Aphrastura (rayaditos) inhabiting the Diego Ramírez Archipelago, the southernmost point of the American continent. This archipelago is geographically isolated and lacks terrestrial mammalian predators as well as woody plants, providing a contrasted habitat to the forests inhabited by the other two Aphrastura spp. Individuals of Diego Ramírez differ morphologically from Aphrastura spinicauda, the taxonomic group they were originally attributed to, by their larger beaks, longer tarsi, shorter tails, and larger body mass. These birds move at shorter distances from ground level, and instead of nesting in cavities in trees, they breed in cavities in the ground, reflecting different life-histories. Both taxa are genetically differentiated based on mitochondrial and autosomal markers, with no evidence of current gene flow. Although further research is required to define how far divergence has proceeded along the speciation continuum, we propose A. subantarctica as a new taxonomic unit, given its unique morphological, genetic, and behavioral attributes in a non-forested habitat. The discovery of this endemic passerine highlights the need to monitor and conserve this still-pristine archipelago devoid of exotic species, which is now protected by the recently created Diego Ramírez Islands-Drake Passage Marine Park.Ítem Variation in fine-scale genetic structure and local dispersal patterns between peripheral populations of a South American passerine bird(John Wiley and Sons, 2017-09) Botero-Delgadillo, E.; Quirici, V.; Poblete, Y.; Cuevas, É.; Kuhn, S.; Girg, A.; Teltscher, K.; Poulin, E.; Kempenaers, B.; Vásquez, R.A.The distribution of suitable habitat influences natal and breeding dispersal at small spatial scales, resulting in strong microgeographic genetic structure. Although environmental variation can promote interpopulation differences in dispersal behavior and local spatial patterns, the effects of distinct ecological conditions on within-species variation in dispersal strategies and in fine-scale genetic structure remain poorly understood. We studied local dispersal and fine-scale genetic structure in the thorn-tailed rayadito (Aphrastura spinicauda), a South American bird that breeds along a wide latitudinal gradient. We combine capture-mark-recapture data from eight breeding seasons and molecular genetics to compare two peripheral populations with contrasting environments in Chile: Navarino Island, a continuous and low density habitat, and Fray Jorge National Park, a fragmented, densely populated and more stressful environment. Natal dispersal showed no sex bias in Navarino but was female-biased in the more dense population in Fray Jorge. In the latter, male movements were restricted, and some birds seemed to skip breeding in their first year, suggesting habitat saturation. Breeding dispersal was limited in both populations, with males being more philopatric than females. Spatial genetic autocorrelation analyzes using 13 polymorphic microsatellite loci confirmed the observed dispersal patterns: a fine-scale genetic structure was only detectable for males in Fray Jorge for distances up to 450 m. Furthermore, two-dimensional autocorrelation analyzes and estimates of genetic relatedness indicated that related males tended to be spatially clustered in this population. Our study shows evidence for context-dependent variation in natal dispersal and corresponding local genetic structure in peripheral populations of this bird. It seems likely that the costs of dispersal are higher in the fragmented and higher density environment in Fray Jorge, particularly for males. The observed differences in microgeographic genetic structure for rayaditos might reflect the genetic consequences of population-specific responses to contrasting environmental pressures near the range limits of its distribution.