The hypothesis that eggshell colouration is a sexually selected trait of female birds is based on the fact that biliverdin, the pigment responsible for blue-green colours of the eggshell, is a potent antioxidant and that only females with high antioxidant capacity can deposit higher concentrations of biliverdin as eggshell pigment. Antioxidants (e.g. carotenoids, vitamins) are also abundant in ...

The effects of L-carnitine supplementation (50-500 mg/kg diet) of a practical layer diet, based on maize, soyabean and wheat, on the performance of laying hens and some indices of egg quality were studied for 8 weeks, using 65-week-old hens kept in cages. Albumen quality (albumen height and Haugh (1937) unit score) was improved, while yolk index and yolk colour score were not affected by dietar...

We investigated potential effects of parent-of-origin specific quantitative trait loci (QTL) in chicken. Two divergent egg-layer lines differing in egg quality were reciprocally crossed to produce 305 F2 hens. Searching the genome using models with uni-parental expression, we identified four genome-wide significant QTL with parent-of-origin effects and three highly suggestive QTL affecting age ...

Parasitoid wasps are taxonomically and biologically extremely diverse. A conceptual framework has recently been developed for understanding life-history evolution and diversification in these animals, and it has confirmed that each of two linked life-history traits - the mode of larval development and the temporal pattern of egg maturation - acts as an organiser of life-history. The framework h...

BACKGROUND Trait polymorphism can evolve as a consequence of frequency-dependent selection. Coevolutionary interactions between hosts and parasites may lead to selection on both to evolve extreme phenotypes deviating from the norm, through disruptive selection. METHODOLOGY/PRINCIPAL FINDING Here, we show through detailed field studies and experimental procedures that the ashy-throated parrotb...

In this paper, we provide the first observations of maternal care for the harvestman family Cranaidae. Adult females of two species, Santinezia serratobialis Roewer 1932, which belongs to the group curvipes, and Santinezia sp., which is probably a new species of the group gigantea, were found in association with egg clutches. Since the microhabitats used for oviposition by these species are ver...

Question: Does nest predation influence egg colour appearance among North American and European passerine birds? Analyses of species that lay their eggs directly on the ground provide support for such a contention, but it is less obvious in shrub and canopy nesters. We hypothesized that if predators locate nests by egg colour, nest predation could select for eggs with a less conspicuous backgro...

Abstract The research is devoted to the study of genetic parameters a less studied trait - intensity egg laying on first day female silkworm butterflies. Based experiments conducted in promising lines Line 27 and 28, it was found that variability this Cv = 15,0-15,3%, heritability coefficient h2 0,321-0,340. Also, for time, close positive correlation established between leading reproductive sig...