The objective of the current study was to estimate genetic and phenotypic correlations among feather pecking (FP) behavior and stress response, immune response, and egg quality parameters. These traits have been measured in an F2 cross, coming from a cross between a high and a low FP line of laying hens. Heritabilities (h2) of stress response (32 wk), primary immune response to keyhole limpet h...

Eggs obtained from 46 and 42 weeks old meat (Hybro) and layer (Leghorn) breeders flocks, respectively were used to examine the effects of genetic type of birds and egg size (small, medium and large) on variables of eggshell characteristics and hatchability traits. The variables measured were egg weight (EW), egg surface area (ESA) and eggshell characteristics (shell conductance (EC), per cent s...

Within the Brassicaceae, wild as well crop species are challenged by specialist herbivores including cabbage white butterflies ( Pieris spp.). The crucifer Brassica nigra responds to oviposition synergistic expression of two egg-killing traits. Genotypes that express a hypersensitive response (HR)-like necrosis (direct egg-killing) also emit oviposition-induced plant volatiles (OIPVs) attractin...

the purpose of this study was to investigate the relationship of maternal breeding values of the weight of day-old chick chicks in a commercial broiler line with egg traits including yolk fatty acids. maternal breeding values of 63 hens of known pedigree were estimated through an animal model, containing direct additive genetic effect, maternal additive genetic effect, maternal common environme...

Inbreeding rate and effects on production (body weight, age at first egg, egg weight), and reproduction (per cent of eggs fertilized, per cent of eggs hatched as related to eggs set) traits were evaluated in 9194 layers belonging to two strains. The individual inbreeding coefficients were calculated using Wright’s formula from available performance records across nine generations. The inbreedin...

Although, beetles of the genus Tribolium first evolved as saprophylic insects, they have adapted to the stored products environment for several thousand years. In this study reproductive strategies are described for eight species of Tribolium that are known to occur in this environment. Experiments were conducted under the same conditions for every species, and several life history traits, incl...

Coevolution between male and female traits can result from correlated responses to selection or correlated selection on genetically independent traits. This study examines the possibility that traits involved in precopulatory sexual selection may influence the evolution of traits involved in postcopulatory sexual selection due to the existence of correlated selection or correlated responses to ...

The evolution of elaborate forms of parental care is an important topic in behavioral ecology, yet the factors shaping the evolution of complex suites of parental and offspring traits are poorly understood. Here, we use a multivariate quantitative genetic approach to study phenotypic and genetic correlations between parental and offspring traits in the burying beetle Nicrophorus vespilloides. T...