Early arrival is not associated with more extra-pair fertilizations in a long-distance migratory bird

When assessing the benefits of early arrival date of migratory birds, a hidden and often ignored component of males’ fitness is the higher chance of early-arriving birds to obtain extra-pair fertilizations. Here we investigated how extra-pair paternity might affect the relationship between male arrival date and number of fertilizations in a model study system, the European pied flycatcher Ficedula hypoleuca. For this purpose, we sampled and genotyped breeding pairs, unpaired males and offspring (including embryos from unhatched eggs when possible) of a Dutch pied flycatcher population. Detailed information on arrival date of males, egg laying date of their social mates and nest success was also recorded. Earlyarriving males had early-laying females and males with early-laying females had a higher probability of siring extra-pair eggs and obtain more fertilizations. However, male arrival date alone did not correlate with the probability to gain extra-pair paternity and neither to the amount of fertilized eggs. Both early- and late-arriving males had a higher probability of losing paternity in their own nest compared to birds with an intermediate arrival date. Finally, late-arriving males were more likely to remain unpaired but, interestingly, a few of these birds obtained paternity via extra-pair copulations. Because earlier arrival date did not lead to more extra-pair fertilizations and because such relationship seems to be driven mainly by the female’s laying date, we conclude that the contribution of extra-pair paternity to the overall fitness benefits of early male arrival date is relatively small

Habitat distribution of migratory and sedentary blackcaps Sylvia atricapilla wintering in southern Iberia: a morphological and biogeochemical approach

In migratory species, the way in which conspecifics from different breeding populations 3 are distributed during the non-breeding period is important from and ecological, 4 evolutionary and conservation perspective, but such knowledge is still limited for most 5 species. Migratory and sedentary blackcaps Sylvia atricapilla wintering in southern Spain 6 can occupy two habitat types: forests and shrublands. According to earlier studies, 7 blackcaps prefer forests over shrublands, and residents remain nearly restricted to forests. 8 However, whether migrants with different breeding origin occupy the two habitats 9 differently is unknown. We used morphological and biogeochemical data (hydrogen isotope ratios measured on feathers: δ2 10 Hf), which show variation along the breeding range 11 of the species, to answer this question. Isotope analyses supported the reliability of 12 morphology as a method for distinguishing between migratory and sedentary blackcaps in 13 sympatry, showing that sedentary individuals are rare in shrublands while migratory ones are abundant in both habitat types. However, migratory blackcaps scored similar δ2 14 Hf 15 values in forests and shrublands, and neither did vary in structural size or flight 16 morphology between habitats. Our study suggests that migrants from a wide range of 17 breeding origins end up mixing between forests and shrublands, which may explain the 18 patterns of variation in space and time in the abundance of blackcaps in this area, and 19 supports the view that inequalities may arise among migrants with the same origin but 20 wintering in different habitats. Such inequalities might carry over into other stages of 21 blackcaps’ life cycle contributing to the regulation of its migratory population

Conservación de poblaciones singulares ante el cambio climático: el caso de las currucas capirotadas ibéricas

Depto. de Biodiversidad, Ecología y EvoluciónFac. de Ciencias BiológicasTRUEpu

Feather traits in four southern populations of the Eurasian blackcap Sylvia atricapilla: do altitudinal movements explain the differences?

Moult of birds is shaped by environmental and genetic drivers whose relative contribution to the structure of feathers may differ within and between populations. In this study, we compare some traits of tail feathers (growth bars, mass, rachis width and barb length) between four populations of the Eurasian blackcap Sylvia atricapilla breeding at different elevations within the southwestern Palaearctic. We tested if these traits were related to the primary productivity of habitats (a surrogate of food availability) or were better explained as an adaptation to altitudinal movements. The distribution of primary productivity was positively related to blackcap abundance suggesting that the species tracked the most productive areas to breed. In this environmental setting, wing morphology (wing length, concavity and pointedness) suggested that lowland blackcaps were sedentary while blackcaps from highland areas were involved in altitudinal movements. The feathers of blackcaps inhabiting the highlands showed wider growth bars and rachis than those of the most productive lowland areas but did not differ in feather mass and barb length. Fast feather growth has been related to time constraints to moult and wider rachis to improve flight efficiency in migratory birds. Our results therefore suggest that differences in feather characteristics between southern populations of the Eurasian blackcap are better interpreted as an adaptive response to altitudinal migration than as a consequence of regional food availability

El análisis de isótopos estables revela sesgos en el funcionamiento de un método morfológico para diferenciar el comportamiento migratorio de los petirrojos Erithacus rubecula

Morphological methods to distinguish between avian groups of research interest (e.g. different sexes, populations or cryptic species) need to be externally validated to ensure reliable performance across situations. In this study, we used stable hydrogen isotope ratios of feathers (δ2Hf) to test the validity of morphological classification functions (MCFs) previously designed to assess the migratory behaviour of European Robins Erithacus rubecula wintering in southern Iberia. Our results show that a great number of migrants (mostly females and juveniles) were erroneously assigned as sedentary, which could compromise the reliability of previous ecological studies that made use of these MCFs. The development of improved MCFs or the use of alternative differentiation methods (δ2Hf) could help us to gain a more realistic insight into the habitat distribution and ecological interactions of sympatric migratory and sedentary robins overwintering in southern Iberia.Los métodos morfológicos para distinguir grupos de aves con interés de investigación (e.g. distinción de sexos, poblaciones o especies crípticas) requieren de validación independiente para asegurar su funcionamiento adecuado de forma consistente. En este estudio, usamos la relación de isótopos estables del hidrógeno en las plumas (δ2Hf) para comprobar la validez de las funciones de clasificación morfológicas (MCFs) diseñadas con anterioridad para identificar el comportamiento migratorio de los petirrojos Erithacus rubecula invernantes en el sur ibérico. Los resultados revelaron que un gran número de migrantes (sobre todo hembras y jóvenes) fueron clasificados erróneamente como sedentarios, lo que podría comprometer la fiabilidad de los estudios ecológicos previos que han hecho uso de estas MCFs. El desarrollo de MCFs mejoradas o el uso de métodos de diferenciación alternativos (δ2Hf) podrían ayudarnos a obtener una idea más realista acerca de la distribución entre hábitats e interacciones ecológicas de los petirrojos migratorios y sedentarios que invernan en simpatría en el sur ibérico

Treatment with tocilizumab or corticosteroids for COVID-19 patients with hyperinflammatory state: a multicentre cohort study (SAM-COVID-19)

Objectives: The objective of this study was to estimate the association between tocilizumab or corticosteroids and the risk of intubation or death in patients with coronavirus disease 19 (COVID-19) with a hyperinflammatory state according to clinical and laboratory parameters. Methods: A cohort study was performed in 60 Spanish hospitals including 778 patients with COVID-19 and clinical and laboratory data indicative of a hyperinflammatory state. Treatment was mainly with tocilizumab, an intermediate-high dose of corticosteroids (IHDC), a pulse dose of corticosteroids (PDC), combination therapy, or no treatment. Primary outcome was intubation or death; follow-up was 21 days. Propensity score-adjusted estimations using Cox regression (logistic regression if needed) were calculated. Propensity scores were used as confounders, matching variables and for the inverse probability of treatment weights (IPTWs). Results: In all, 88, 117, 78 and 151 patients treated with tocilizumab, IHDC, PDC, and combination therapy, respectively, were compared with 344 untreated patients. The primary endpoint occurred in 10 (11.4%), 27 (23.1%), 12 (15.4%), 40 (25.6%) and 69 (21.1%), respectively. The IPTW-based hazard ratios (odds ratio for combination therapy) for the primary endpoint were 0.32 (95%CI 0.22-0.47; p < 0.001) for tocilizumab, 0.82 (0.71-1.30; p 0.82) for IHDC, 0.61 (0.43-0.86; p 0.006) for PDC, and 1.17 (0.86-1.58; p 0.30) for combination therapy. Other applications of the propensity score provided similar results, but were not significant for PDC. Tocilizumab was also associated with lower hazard of death alone in IPTW analysis (0.07; 0.02-0.17; p < 0.001). Conclusions: Tocilizumab might be useful in COVID-19 patients with a hyperinflammatory state and should be prioritized for randomized trials in this situatio

Role of age and comorbidities in mortality of patients with infective endocarditis

[Purpose]: The aim of this study was to analyse the characteristics of patients with IE in three groups of age and to assess the ability of age and the Charlson Comorbidity Index (CCI) to predict mortality. [Methods]: Prospective cohort study of all patients with IE included in the GAMES Spanish database between 2008 and 2015.Patients were stratified into three age groups:<65 years,65 to 80 years,and ≥ 80 years.The area under the receiver-operating characteristic (AUROC) curve was calculated to quantify the diagnostic accuracy of the CCI to predict mortality risk. [Results]: A total of 3120 patients with IE (1327 < 65 years;1291 65-80 years;502 ≥ 80 years) were enrolled.Fever and heart failure were the most common presentations of IE, with no differences among age groups.Patients ≥80 years who underwent surgery were significantly lower compared with other age groups (14.3%,65 years; 20.5%,65-79 years; 31.3%,≥80 years). In-hospital mortality was lower in the <65-year group (20.3%,<65 years;30.1%,65-79 years;34.7%,≥80 years;p < 0.001) as well as 1-year mortality (3.2%, <65 years; 5.5%, 65-80 years;7.6%,≥80 years; p = 0.003).Independent predictors of mortality were age ≥ 80 years (hazard ratio [HR]:2.78;95% confidence interval [CI]:2.32–3.34), CCI ≥ 3 (HR:1.62; 95% CI:1.39–1.88),and non-performed surgery (HR:1.64;95% CI:11.16–1.58).When the three age groups were compared,the AUROC curve for CCI was significantly larger for patients aged <65 years(p < 0.001) for both in-hospital and 1-year mortality. [Conclusion]: There were no differences in the clinical presentation of IE between the groups. Age ≥ 80 years, high comorbidity (measured by CCI),and non-performance of surgery were independent predictors of mortality in patients with IE.CCI could help to identify those patients with IE and surgical indication who present a lower risk of in-hospital and 1-year mortality after surgery, especially in the <65-year group

Comportamiento migratorio y estrategias de muda en paseriformes

En las aves, las presiones temporales que implica la migración han conducido a una reducción de la duración del proceso de sustitución del plumaje (muda). Sin embargo, esta aceleración de la muda está asociada con la producción de plumas de menor masa y menor complejidad estructural, lo que puede afectar a su funcionalidad. Dado que un plumaje de baja calidad reduciría la eficacia biológica de las aves, y especialmente la de aquellas que deben afrontar los exigentes desplazamientos migratorios, las aves migratorias han desarrollado diversos mecanismos de compensación. Por un lado, algunas especies migratorias transaharianas han optado por modificar la ubicación temporal de la muda. De esta forma, han trasladado el proceso de muda al periodo invernal para evitar las limitaciones temporales que supone mudar en verano. A su vez, esto les permite obtener plumas más complejas y pesadas. Por otro lado, en las especies en las que un cambio fenológico de la muda no parece viable, las aves han optado por otras soluciones menos perceptibles. En primer lugar, y suponiendo que las aves migratorias pueden optimizar el uso de los recursos disponibles para la síntesis del plumaje, asignan más material a los tractos del plumaje que tienen mayor relevancia funcional (por ejemplo, las plumas primarias del ala). En segundo lugar, a igualdad de inversión de material en las plumas, las aves migratorias parecen capaces de obtener plumas con mejores propiedades mecánicas que sus equivalentes sedentarias. Esta Tesis señala la importancia de la migración, y sus costes asociados, en la variación de las estrategias de muda de las aves, sugiriendo la existencia de una compleja serie de ajustes de la muda que han podido evolucionar integrados con otro tipo de rasgos morfológicos, fisiológicos y del comportamiento en las aves migratorias

Evolution of seasonal transmission patterns in avian blood-borne parasites

In temperate regions, many vector-borne parasites maximise their transmission prospects by adjusting reproduction to seasonal cycles of host susceptibility and vector availability. Nevertheless, in these regions there are areas where environmental conditions are favourable throughout the year, so that parasites could benefit from a year-round transmission strategy. We analysed how different transmission strategies (strict summer transmission, extended summer transmission – including spring and autumn, and year round transmission) have evolved among the different genetic lineages of Haemoproteus parabelopolskyi, an avian blood-borne parasite shared by three sibling species of passerine hosts. Our results indicate that the ancestral state of this clade of parasites had a strict summer transmission with the blackcap (Sylvia atricapilla) as the host. Other transmission strategies and switches to the other host species (Sylvia abyssinica and Sylviaborin) evolved recently, several times, independently. This suggests that, although year-round transmission is ecologically successful at present, seasonal transmission may have become more stable over evolutionary time. Switches from strict summer to an extended or year-round transmission strategy could have ecological consequences, if they promote the spread of parasites into more distant regions, transported by the migrating bird hosts. Therefore, a deeper knowledge of how different parasite transmission strategies are structured among birds in temperate areas is essential for understanding how disease emergence risks may develop in the future

High diversity and low genetic structure of feather mites associated with a phenotypically variable bird host

Obligate symbionts may be genetically structured among host individuals and among phenotypically distinct host populations. Such processes may in turn determine within-host genetic diversity of symbionts, which is relevant for understanding symbiont population dynamics. We analysed the population genetic structure of two species of feather mites (Proctophyllodes sylviae and Trouessartia bifurcata) in migratory and resident blackcaps Sylvia atricapilla that winter sympatrically. Resident and migratory hosts may provide mites with habitats of different qualities, what might promote specialization of mite populations. We found high genetic diversity of within-host populations for both mite species, but no sign of genetic structure of mites between migratory and resident hosts. Our results suggest that, although dispersal mechanisms between hosts during the non-breeding season are unclear, mite populations are not limited by transmission bottlenecks that would reduce genetic diversity among individuals that share a host. Additionally, there is no evidence that host phenotypic divergence (associated with the evolution of migration and residency) has promoted the evolution of host-specialist mite populations. Unrestricted dispersal among host types may allow symbiotic organisms to avoid inbreeding and to persist in the face of habitat heterogeneity in phenotypically diverse host populations