Effects of Experimental Brood Size Manipulation and Gender on Carotenoid Levels of Eurasian Kestrels Falco tinnunculus

Animals use carotenoid-pigments for coloration, as antioxidants and as enhancers of the immune system. Carotenoid-dependent colours can thus signal individual quality and carotenoids have also been suggested to mediate life-history trade-offs.

Evolutionary aspects of population structure for molecular and quantitative traits in the freshwater snail Radix balthica.

Detecting the action of selection in natural populations can be achieved using the QST-FST comparison that relies on the estimation of FST with neutral markers, and QST using quantitative traits potentially under selection. QST higher than FST suggests the action of directional selection and thus potential local adaptation. In this article, we apply the QST-FST comparison to four populations of the hermaphroditic freshwater snail Radix balthica located in a floodplain habitat. In contrast to most studies published so far, we did not detect evidence of directional selection for local optima for any of the traits we measured: QST calculated using three different methods was never higher than FST. A strong inbreeding depression was also detected, indicating that outcrossing is probably predominant over selfing in the studied populations. Our results suggest that in this floodplain habitat, local adaptation of R. balthica populations may be hindered by genetic drift, and possibly altered by uneven gene flow linked to flood frequency

Landscape homogenization due to agricultural intensification disrupts the relationship between reproductive success and main prey abundance in an avian predator

Selecting high-quality habitat and the optimal time to reproduce can increase individual fitness and is a strong evolutionary factor shaping animal populations. However, few studies have investigated the interplay between land cover heterogeneity, limitation in food resources, individual quality and spatial variation in fitness parameters. Here, we explore how individuals of different quality respond to possible mismatches between a cue for prey availability (land cover heterogeneity) and the actual fluctuating prey abundance.Peer reviewe

Haematozoan infections in the Eurasian kestrel:Effects of fluctuating food supply and experimental manipulation of parental effort

The influence of parental effort on susceptibility to parasitism was investigated experimentally in the Eurasian kestrel (Falco tinnunculus) in Finland. Parental effort was manipulated by either enlarging or reducing broods by 1-2 young, while unmanipulated broods served as controls. This was done during 3 breeding seasons, during which the densities of the major prey of kestrels (voles) were relatively low, high and intermediate, respectively. Two, taxon specific, methods were applied for determining the prevalence (per cent individuals infected) of extracellular Trypanosoma spp. and intracellular Haemoproteus spp. infection. Blood samples were taken from females during the incubation phase, and from both parents during the mid-nestling phase. Trypanosoma was more prevalent when food was less available. Furthermore, the increase in the prevalence of Trypanosoma among females was most pronounced during the poor vole year. In contrast, Haemoproteus infection seemed not closely related to annual supply of main prey. Manipulations of parental effort were related to parental infection, but the effect differed between genders. The prevalence of Trypanosoma in males (main provider of young) increased with experimental brood size, and there was an interaction between food supply and brood size manipulation so that the difference in prevalences between reduced and enlarged broods increased with decreasing food supply. Among females, no such an interaction was found. Instead, the effect of brood enlargement on Trypanosoma prevalence of females was apparent in the pear of relatively high vole densities only. Manipulation of brood size did not have clear effects on Haemoproteus infection in either gender. These results support the idea that increased parental effort may make hosts susceptible to haematozoan infection, and are the first to suggest that resource levels (food supply) can modify the susceptibility, indicating that the magnitude of reproductive costs can be attributed to Variation in environmental conditions

Resource levels, reproduction and resistance to haematozoan infections

Compromise of immune function during reproduction may form a link between parental effort and the cost of reproduction, but the role of environmental variation in structuring intra-individual life-history trade-offs has been poorly investigated. We manipulated the need for parental effort in Eurasian kestrels, Falco tinnunculus, by food-supplementing broods for three nestling periods, during which the natural main food supply (voles) varied, and found that parental parasitaemia was inversely related to yearly vole densities. The level of parasitaemia in females was, however, reduced by food supplements. No effect on males was expected, as earlier work has shown that only females responded to the supplements by changing their behaviour. We show directly that the likelihood of female parasitaemia was diminished by spending less time in flight-hunting, which was related to reproduction during a good vole year, to our supplementary feeding, and to being mated to a male with high parental effort. Our results represent a novel direct benefit for females in resource - providing species, linked to female, as well as offspring, well-being, and they provide insight into why the appearance of reproductive costs may be linked to gender or environmental conditions

Adherence to the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist in articles published in EAACI Journals: A bibliographic study

Research data derived from observational studies are accumulating quickly in the field of allergy and immunology and a large amount of observational studies are published every year. The aim of the present study was to evaluate the adherence to the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist by papers published in the three European Academy of Allergy and Clinical Immunology journals, during the period 2009–2018. To this end, we conducted a bibliographic study of up to eight randomly selected papers per year per Journal. Our literature search resulted in 223 papers. Amongst those, 80, 80 and 63 records were from Paediatric Allergy and Immunology, Allergy and Clinical and Translational Allergy, respectively; the latter was published only from 2011 on. Prospective, case control and cross-sectional designs were described in 88, 43 and 92 papers, respectively. Full reporting of all STROBE items was present in 47.4%, 45.6% and 41.2% for the cohort, cross-sectional and case-control studies, respectively. Generally, no time trend in adherence of reporting STROBE items was observed, apart from reporting funding, which increased from 60% in 2009/2010 to more than 90% in 2018. We identified a cluster of STROBE items with low proportions of full reporting constituted by the items on reporting study design in the title and methods, variables types along with their measurement/assessment, bias and confounding, study size, and grouping of variables. It appears that the STROBE checklist is a suitable tool in observational allergy epidemiology. However, adherence to the STROBE checklist appeared suboptimal

Kinetics of stepwise nitrogen adsorption by size-selected iron cluster cations: Evidence for size-dependent nitrogen phobia

We present a study of stepwise cryogenic N2 adsorption on size-selected Fen+ (n = 8–20) clusters within a hexapole collision cell held at T = 21–28 K. The stoichiometries of the observed adsorption limits and the kinetic fits of stepwise N2 uptake reveal cluster size-dependent variations that characterize four structural regions. Exploratory density functional theory studies support tentative structural assignment in terms of icosahedral, hexagonal antiprismatic, and closely packed structural motifs. There are three particularly noteworthy cases, Fe13+ with a peculiar metastable adsorption limit, Fe17+ with unprecedented nitrogen phobia (inefficient N2 adsorption), and Fe18+ with an isomeric mixture that undergoes relaxation upon considerable N2 uptake

Condition-dependent expression of melanin-based coloration in the Eurasian kestrel.

Melanin is the most common pigment in animal integuments and is responsible for some of the most striking ornaments. A central tenet of sexual selection theory states that melanin-based traits can signal absolute individual quality in any environment only if their expression is condition-dependent. Significant costs imposed by an ornament would ensure that only the highest quality individuals display the most exaggerated forms of the signal. Firm evidence that melanin-based traits can be condition-dependent is still rare in birds. In an experimental test of this central assumption, we report condition-dependent expression of a melanin-based trait in the Eurasian kestrel (Falco tinnunculus). We manipulated nestling body condition by reducing or increasing the number of nestlings soon after hatching. A few days before fledging, we measured the width of sub-terminal black bands on the tail feathers. Compared to nestlings from enlarged broods, individuals raised in reduced broods were in better condition and thereby developed larger sub-terminal bands. Furthermore, in 2 years, first-born nestlings also developed larger sub-terminal bands than their younger siblings that are in poorer condition. This demonstrates that expression of melanin-based traits can be condition-dependent