| the relationship of telomere length to baseline corticosterone levels in nestlings of an altricial passerine bird in natural populations. | 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. | 2016 | 26759601 |
| baseline corticosterone and stress response in the thorn-tailed rayadito (aphrastura spinicauda) along a latitudinal gradient. | glucocorticoids are essential for life and their secretion is regulated by the hypothalamic-pituitary-adrenal axis (hpa). the hpa axis is often divided into two components: baseline glucocorticoids levels and stress response glucocorticoids levels, which are affected by changes in ambient temperature and productivity among others factors. an approximation to evaluate how a species copes with these changes is to evaluate differences of this hormone amongst populations of the same species that inh ... | 2014 | 24384532 |
| changes in patch features may exacerbate or compensate for the effect of habitat loss on forest bird populations. | one and a half centuries after darwin visited chiloe island, what he described as "…an island covered by one great forest…" has lost two-thirds of its forested areas. at this biodiversity hotspot, forest surface is becoming increasingly fragmented due to unregulated logging, clearing for pastures and replacement by exotic tree plantations. decrease in patch size, increased isolation and "edge effects" can influence the persistence of forest species in remnant fragments. we assessed how these var ... | 2011 | 21738723 |
| on the relationship between baseline corticosterone levels and annual survival of the thorn-tailed rayadito. | baseline concentrations of glucocorticoids (i.e., cortisol and/or corticosterone) can moderately increase with the degree of energy demands that an individual faces. this could be a mechanism based on which glucocorticods (gcs) can mediate life history trade-offs, and therefore fitness. the 'cort-fitness hypothesis' predicts a negative relationship between gcs and fitness, meanwhile the 'cort-adaptation hypothesis' predicts the opposite pattern. field studies on the relation between baseline gcs ... | 2020 | 33017587 |
| range-wide genetic structure in the thorn-tailed rayadito suggests limited gene flow towards peripheral populations. | understanding the population genetic consequences of habitat heterogeneity requires assessing whether patterns of gene flow correspond to landscape configuration. studies of the genetic structure of populations are still scarce for neotropical forest birds. we assessed range-wide genetic structure and contemporary gene flow in the thorn-tailed rayadito (aphrastura spinicauda), a passerine bird inhabiting the temperate forests of south america. we used 12 microsatellite loci to genotype 582 indiv ... | 2020 | 32523081 |
| latitudinal gradients of haemosporidian parasites: prevalence, diversity and drivers of infection in the thorn-tailed rayadito (aphrastura spinicauda). | latitudinal gradients are well-suited systems that may be helpful explaining distribution of haemosporidian parasites and host susceptibility. we studied the prevalence, diversity and drivers of haemosporidian parasites (leucocytozoon, plasmodium and haemoproteus) along a latitudinal gradient (30°-56° s), that encompass the total distribution (~3,000 km) of the thorn-tailed rayadito (aphrastura spinicauda) in the south american temperate forests from chile. we analyzed 516 individuals from 18 lo ... | 2020 | 31879589 |
| variation in fine-scale genetic structure and local dispersal patterns between peripheral populations of a south american passerine bird. | 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 ... | 2017 | 29075455 |