Females of carotenoid-supplemented males are more faithful and produce higher quality offspring

Reproduction is known to increase the basal metabolic rate and generate oxidative stress, a possible proximate cost of reproduction. Carotenoids have been shown to be in vitro antioxidant molecules and, in a number of instances, to contribute in vivo to the antioxidant protection of the organism against the deleterious effects of free radicals and oxidative stress. These compounds are also involved in the up- and downregulation of the immune system. Thus, carotenoids may improve a male's health status and condition during breeding and enhance his attractiveness through, for example, a higher investment into mating activities. The differential allocation hypothesis predicts that females should invest more in reproduction when mated to more attractive partners. Therefore, a supplementary dose of carotenoids during breeding should increase male attractiveness and translate into higher reproductive success via a higher reproductive effort by their mate. We tested this hypothesis in great tits by supplementing males with carotenoids during their female's fertile period. We subsequently transferred entire clutches into unmanipulated foster nests. Thus, any effect of our carotenoid supplementation to males on their reproductive success must be due to female differential reproductive investment. Offspring sired by carotenoid-supplemented males were found to grow bigger and heavier and to fledge more successfully. Carotenoid-supplemented males also lost less paternity. Our results illustrate the fitness benefits males can accrue from carotenoids and underline the selective pressure imposed on males to optimize carotenoid acquisitio

Analysis of genetic parentage in the tawny owl ( Strix aluco ) reveals extra-pair paternity is low

We have investigated genetic parentage in a Swiss population of tawny owls (Strix aluco). To this end, we performed genetic analysis for six polymorphic loci of 49 avian microsatellite loci tested for cross-species amplification. We found one extra-pair young out of 137 (0.7%) nestlings in 37 families (2.7%). There was no intra-specific brood parasitism. Our results are in accordance with previous findings for other raptors and owls that genetic monogamy is the rule. Female tawny owls cannot raise offspring without a substantial contribution by their mates. Hence one favoured hypothesis is that high paternal investment in reproduction selects for behaviour that prevents cuckoldr

Molecular mechanisms of Eda-mediated adaptation to freshwater in threespine stickleback.

A main goal of evolutionary biology is to understand the genetic basis of adaptive evolution. Although the genes that underlie some adaptive phenotypes are now known, the molecular pathways and regulatory mechanisms mediating the phenotypic effects of those genes often remain a black box. Unveiling this black box is necessary to fully understand the genetic basis of adaptive phenotypes, and to understand why particular genes might be used during phenotypic evolution. Here, we investigated which genes and regulatory mechanisms are mediating the phenotypic effects of the Eda haplotype, a locus responsible for the loss of lateral plates and changes in the sensory lateral line of freshwater threespine stickleback (Gasterosteus aculeatus) populations. Using a combination of RNAseq and a cross design that isolated the Eda haplotype on a fixed genomic background, we found that the Eda haplotype affects both gene expression and alternative splicing of genes related to bone development, neuronal development and immunity. These include genes in conserved pathways, like the BMP, netrin and bradykinin signalling pathways, known to play a role in these biological processes. Furthermore, we found that differentially expressed and differentially spliced genes had different levels of connectivity and expression, suggesting that these factors might influence which regulatory mechanisms are used during phenotypic evolution. Taken together, these results provide a better understanding of the mechanisms mediating the effects of an important adaptive locus in stickleback and suggest that alternative splicing could be an important regulatory mechanism mediating adaptive phenotypes

Low but contrasting neutral genetic differentiation shaped by winter temperature in European great tits

Gene flow is usually thought to reduce genetic divergence and impede local adaptation by homogenising gene pools between populations. However, evidence for local adaptation and phenotypic differentiation in highly mobile species, experiencing high levels of gene flow, is emerging. Assessing population genetic structure at different spatial scales is thus a crucial step towards understanding mechanisms underlying intraspecific differentiation and diversification. Here, we studied the population genetic structure of a highly mobile species – the great tit Parus major – at different spatial scales. We analysed 884 individuals from 30 sites across Europe including 10 close-by sites (< 50 km), using 22 microsatellite markers. Overall we found a low but significant genetic differentiation among sites (FST = 0.008). Genetic differentiation was higher, and genetic diversity lower, in south-western Europe. These regional differences were statistically best explained by winter temperature. Overall, our results suggest that great tits form a single patchy metapopulation across Europe, in which genetic differentiation is independent of geographical distance and gene flow may be regulated by environmental factors via movements related to winter severity. This might have important implications for the evolutionary trajectories of sub-populations, especially in the context of climate change, and calls for future investigations of local differences in costs and benefits of philopatry at large scales

Drinking to ease the burden: a cross-sectional study on trauma, alcohol abuse and psychopathology in a post-conflict context

Ertl V, Saile R, Neuner F, Catani C. Drinking to ease the burden: a cross-sectional study on trauma, alcohol abuse and psychopathology in a post-conflict context. BMC Psychiatry. 2016;16(1): 202.Background It is likely that alcohol use and abuse increase during and after violent conflicts. The most prominent explanation of this phenomenon has been referred to as self-medication hypothesis. It predicts that psychotropic substances are consumed to deal with conflict-related psychic strains and trauma. In northern Uganda, a region that has been affected by a devastating civil war and is characterized by high levels of alcohol abuse we examined the associations between war-trauma, childhood maltreatment and problems related to alcohol use. Deducing from the self-medication hypothesis we assumed alcohol consumption moderates the relationship between trauma-exposure and psychopathology. Methods A cross-sectional epidemiological survey targeting war-affected families in post-conflict northern Uganda included data of male (n = 304) and female (n = 365) guardians. We used standardized questionnaires in an interview format to collect data on the guardians’ socio-demography, trauma-exposure, alcohol consumption and symptoms of alcohol abuse, PTSD and depression. Results Symptoms of current alcohol use disorders were present in 46 % of the male and 1 % of the female respondents. A multiple regression model revealed the unique contributions of emotional abuse in the families of origin and trauma experienced outside the family-context in the prediction of men’s alcohol-related symptoms. We found that alcohol consumption moderated the dose-effect relationship between trauma-exposure and symptoms of depression and PTSD. Significant interactions indicated that men who reported more alcohol-related problems experienced less increase in symptoms of PTSD and depression with increasing trauma-exposure. Conclusions The gradual attenuation of the dose-effect the more alcohol-related problems were reported is consistent with the self-medication hypothesis. Hence, the functionality of alcohol consumption has to be considered when designing and implementing addiction treatment in post-conflict contexts

Body measures and heterozygosity levels

This data set includes nestling body measures and heterozygosity levels of nestlings and rearing parents. Nest_ID: Nest of rearing, Chick_ID: Individual nestling's code, Brood_manipul: Brood size manipulation treatment, Infestation: Flea infestation, Original_brood: Brood size before manipulation treatment, HetHLm(f)_f: Functional heterozygosity of foster male (female), HetHLm(f)_n: Neutral heterozygosity of foster male (female), HetHL_f: Nestling functional heterozygosity, HetHL_n: Nestling neutral heterozygosity, Sex: Nestling sex, Weight_d15: Nestling weight 15 days after hatching, Fledged: 1=nestling successfully fledged, 0= nestling died, LPS_response: Difference in thickness measure before and after LPS-Injection, Rank: Nestling hatching rank, Body_cond: Nestling body conditio

Data from: Heterozygosity is linked to the costs of immunity in nestling great tits (Parus major)

There is growing evidence that heterozygosity–fitness correlations (HFCs) are more pronounced under harsh conditions. Empirical evidence suggests a mediating effect of parasite infestation on the occurrence of HFCs. Parasites have the potential to mediate HFCs not only by generally causing high stress levels but also by inducing resource allocation tradeoffs between the necessary investments in immunity and other costly functions. To investigate the relative importance of these two mechanisms, we manipulated growth conditions of great tit nestlings by brood size manipulation, which modifies nestling competition, and simultaneously infested broods with ectoparasites. We investigated under which treatment conditions HFCs arise and, second, whether heterozygosity is linked to tradeoff decisions between immunity and growth. We classified microsatellites as neutral or presumed functional and analyzed these effects separately. Neutral heterozygosity was positively related to the immune response to a novel antigen in parasite-free nests, but not in infested nests. For nestlings with lower heterozygosity levels, the investments in immunity under parasite pressure came at the expenses of reduced feather growth, survival, and female body condition. Functional heterozygosity was negatively related to nestling immune response regardless of the growth conditions. These contrasting effects of functional and neutral markers might indicate different underlying mechanisms causing the HFCs. Our results confirm the importance of considering marker functionality in HFC studies and indicate that parasites mediate HFCs by influencing the costs of immune defense rather than by a general increase in environmental harshness levels

Single locus heterozygosity

Single locus heterozygosity for all individual nestlings. 0=homozygous, 1=heterozygous