Descriptions of the laying behaviours of obligate brood parasites such as the brown-headed cowbird, Molothrus ater, typically fall into one of two categories. These categories are ‘shotgun behaviour’, where females are predicted to distribute their eggs apparently at random between available host nests, or ‘host selection behaviour’, where females lay their eggs discriminately, placing them int...

Many organisms exhibit distinct breeding seasons tracking food availability. If conspecific populations inhabit areas that experience different temporal cycles in food availability spurred by variation in precipitation regimes, then they should display asynchronous breeding seasons. Thus, such populations might exhibit a temporal barrier to gene flow, which may potentially promote genetic diffe...

The low-light tolerance index was investigated in a set of 123 F2:3 lines during the seedling stage across 2 seasons, and the heredity of low-light tolerance was assessed via different ge-netic analysis methods. The results of the classical analysis showed that low-light tolerance is controlled by an additive-dominant poly-gene, and the polygenic inheritance rate of separate generations was >30...

Most of our knowledge about avian haemosporidian parasites comes from the Hawaiian archipelago, where recently introduced Plasmodiumrelictum has contributed to the extinction of many endemic avian species. While the ecology of invasive malaria is reasonably understood, the ecology of endemic haemosporidian infection in mainland systems is poorly understood, even though it is the rule rather tha...

Despite low levels of organochlorine contaminants (OCs) in Antarctic biota, some compounds may exceed the levels in equivalent Arctic species, and previous studies have found biochemical evidence of pollutant exposure in south polar skuas (Catharacta maccormicki), a common marine top predator in the region. In this study we examined relationships between fitness components (fecundity and adult ...

Reproductive traits of purebred and crossbred pigs produced in a four-breed diallel mating system using the Duroc, Landrace, Spotted and Yorkshire breeds were collected for five consecutive farrowing seasons (two farrowing seasons/year) beginning in fall 1976. Paternal half-sib heritabilities and genetic correlations for testicular traits (120 boars from 36 sires), serum testosterone (TE) and l...

In this study, conducted in two different seasons, we aimed to choose parents to obtain promising segregating populations for the extraction of black bean (Phaseolus vulgaris L.) lines that are superior in terms of disease resistance, plant architecture, and grain yield. Twelve parents were arranged in two groups to compose a partial diallel in a 5 x 7 scheme. Group 1 was composed of parents wi...

Density dependence in vital rates is key to population regulation. Rather than being constant, the strength of density dependence may vary throughout the year, but empirical evidence is limited. Based on 22 years of data of color-banded birds from a recovering population of Eurasian Spoonbills Platalea leucorodia leucorodia, we show, for the first time, seasonal variation in density dependence ...

Berry firmness is one of the most important quality traits in table grape production and, consequently, a key aspect for table grape breeding programs. To identify the genes determining the berry firmness in grapes, a progeny of Ruby Seedless × Sultanina (n = 137) was evaluated during three consecutive seasons. Results showed that even though the heritability was ~90%, season had an important e...