Age-related change in melanin-based coloration of Barn owls (Tyto alba): females that become more female-like and males that become more male-like perform better

Ornament expression fluctuates with age in many organisms. Whether these changes are adaptively plastic is poorly known. In order to understand the ultimate function of melanin-based ornaments, we studied their within-individual fluctuations and their covariation with fitness-related traits. In barn owls (Tyto alba), individuals vary from reddish-brown pheomelanic to white and from immaculate to marked with black eumelanic spots, males being less reddish and less spotted than females. During the first molt, both sexes became less pheomelanic, females displayed larger spots and males fewer spots, but the extent of these changes was not associated with reproduction. At subsequent molts, intra-individual changes in melanin-based traits covaried with simultaneous reproduction changes. Adult females bred earlier in the season and laid larger eggs when they became scattered with larger spots, while adults of both sexes produced larger broods when they became whiter. These results suggest that the production of melanin pigments and fitness-related life history traits are concomitantly regulated in a sex-specific way.

Interactions of dietary whole-grain intake with fasting glucose- and insulin-related genetic loci in individuals of European descent: a meta-analysis of 14 cohort studies.

Whole-grain foods are touted for multiple health benefits, including enhancing insulin sensitivity and reducing type 2 diabetes risk. Recent genome-wide association studies (GWAS) have identified several single nucleotide polymorphisms (SNPs) associated with fasting glucose and insulin concentrations in individuals free of diabetes. We tested the hypothesis that whole-grain food intake and genetic variation interact to influence concentrations of fasting glucose and insulin. Via meta-analysis of data from 14 cohorts comprising ∼ 48,000 participants of European descent, we studied interactions of whole-grain intake with loci previously associated in GWAS with fasting glucose (16 loci) and/or insulin (2 loci) concentrations. For tests of interaction, we considered a P value <0.0028 (0.05 of 18 tests) as statistically significant. Greater whole-grain food intake was associated with lower fasting glucose and insulin concentrations independent of demographics, other dietary and lifestyle factors, and BMI (β [95% CI] per 1-serving-greater whole-grain intake: -0.009 mmol/l glucose [-0.013 to -0.005], P < 0.0001 and -0.011 pmol/l [ln] insulin [-0.015 to -0.007], P = 0.0003). No interactions met our multiple testing-adjusted statistical significance threshold. The strongest SNP interaction with whole-grain intake was rs780094 (GCKR) for fasting insulin (P = 0.006), where greater whole-grain intake was associated with a smaller reduction in fasting insulin concentrations in those with the insulin-raising allele. Our results support the favorable association of whole-grain intake with fasting glucose and insulin and suggest a potential interaction between variation in GCKR and whole-grain intake in influencing fasting insulin concentrations.

Traditional local medicines in the republic of Palau and non-communicable diseases (NCD), signs of effectiveness.

ETHNOPHARMACOLOGICAL RELEVANCE: The aim of this survey was to describe which traditional medicines (TM) are most commonly used for non-communicable diseases (NCD - diabetes, hypertension related to excess weight and obesity) in Pacific islands and with what perceived effectiveness. NCD, especially prevalent in the Pacific, have been subject to many public health interventions, often with rather disappointing results. Innovative interventions are required; one hypothesis is that some local, traditional approaches may have been overlooked. MATERIALS AND METHODS: The method used was a retrospective treatment-outcome study in a nation-wide representative sample of the adult population (about 15,000 individuals) of the Republic of Palau, an archipelago of Micronesia. RESULTS: From 188 respondents (61% female, age 16-87, median 48,), 30 different plants were used, mostly self-prepared (69%), or from a traditional healer (18%). For excess weight, when comparing the two most frequent plants, Morinda citrifolia L. was associated with more adequate outcome than Phaleria nishidae Kaneh. (P=0.05). In case of diabetes, when comparing Phaleria nishidae (=Phaleria nisidai) and Morinda citrifolia, the former was statistically more often associated with the reported outcome "lower blood sugar" (P=0.01). CONCLUSIONS: Statistical association between a plant used and reported outcome is not a proof of effectiveness or safety, but it can help select plants of interest for further studies, e.g. through a reverse pharmacology process, in search of local products which may have a positive impact on population health.

Statistical hypothesis testing and common misinterpretations: should we abandon p-value in forensic science applications?

Many people regard the concept of hypothesis testing as fundamental to inferential statistics. Various schools of thought, in particular frequentist and Bayesian, have promoted radically different solutions for taking a decision about the plausibility of competing hypotheses. Comprehensive philosophical comparisons about their advantages and drawbacks are widely available and continue to span over large debates in the literature. More recently, controversial discussion was initiated by an editorial decision of a scientific journal [1] to refuse any paper submitted for publication containing null hypothesis testing procedures. Since the large majority of papers published in forensic journals propose the evaluation of statistical evidence based on the so called p-values, it is of interest to expose the discussion of this journal's decision within the forensic science community. This paper aims to provide forensic science researchers with a primer on the main concepts and their implications for making informed methodological choices.

Sex- and melanism-specific variations in the oxidative status of adult tawny owls in response to manipulated reproductive effort.

Oxidative stress, determined by the balance between the production of damaging reactive oxygen species (ROS) and antioxidant defences, is hypothesized to play an important role in shaping the cost of reproduction and life history trade-offs. To test this hypothesis, we manipulated reproductive effort in 94 breeding pairs of tawny owls (Strix aluco) to investigate the sex- and melanism-specific effects on markers of oxidative stress in red blood cells (RBCs). This colour polymorphic bird species shows sex-specific division of labour and melanism-specific history strategies. Brood sizes at hatching were experimentally enlarged or reduced to increase or decrease reproductive effort, respectively. We obtained an integrative measure of the oxidative balance by measuring ROS production by RBCs, intracellular antioxidant glutathione levels and membrane resistance to ROS. We found that light melanic males (the sex undertaking offspring food provisioning) produced more ROS than darker conspecifics, but only when rearing an enlarged brood. In both sexes, light melanic individuals had also a larger pool of intracellular antioxidant glutathione than darker owls under relaxed reproductive conditions (i.e. reduced brood), but not when investing substantial effort in current reproduction (enlarged brood). Finally, resistance to oxidative stress was differently affected by the brood size manipulation experiment in males and females independently of their plumage coloration. Altogether, our results support the hypothesis that reproductive effort can alter the oxidative balance in a sex- and colour-specific way. This further emphasizes the close link between melanin-based coloration and life history strategies.