Search results for " selection"
showing 10 items of 1271 documents
Color Signals in the Black Grouse (Tetrao tetrix): Signal Properties and Their Condition Dependency
2009
Recent progress in techniques of quantifying between-individual differences of color-based ornaments has revealed undiscovered possibilities for research in sexual selection. We present how the color spectra data can be comprehensively used for studying the importance of sexual ornaments in the black grouse and how these ornaments are related to a male condition. For this, we used both correlative field and experimental data. Field data indicated that older males had more chromatic coloration than yearlings. Blue chroma of males was correlated with male mating success. We experimentally manipulated yearling birds with testosterone implants and found that testosterone-implanted males had imp…
Parental effects on offspring longevity--evidence from 17th to 19th century reproductive histories.
2004
Family studies provide support for a modest genetic influence on offspring life span, although the magnitude of these correlations is small.The study aimed to clarify the relative contributions of parental age at birth and overall parental longevity on offspring lifespan, and to identify the biological and cultural mechanisms.Information was derived from two village genealogies (1650-1927) encompassing 9979 births (5315 males, 4664 females). Data selection was guided by the inclusion of information about parental age at birth and lifespan, offspring lifespan and cohort-specific life expectancy.Parental age at reproduction displayed a negative association with offspring survivability, which …
Female control of paternity in the sexually cannibalistic spider Argiope keyserlingi.
2000
Sexual conflict theory predicts an antagonistic coevolution, with each sex evolving adaptations and counter-adaptations to overcome a temporary dominance of the other sex over the control of paternity. Polyandry allows sexual selection to operate after mating has commenced, with male and female interests competing for control of fertilization. There are numerous examples of male control of paternity, but few studies have unambiguously revealed female control. Attributing variance in paternity to females is often difficult since male and female influences cannot be separated unambiguously. However, we show that polyandrous female orb-web spiders Argiope keserlingi (Arancidae) control the pat…
Functional annulus remodelling using a prosthetic ring in tricuspid aortic valve repair: mid-term results
2013
OBJECTIVES: The functional aortic valve annulus (FAVA) is a complex unit with proximal (aorto-ventricular junction) and distal (sinotubular junction) components. The aim of our study was to evaluate the impact of the total FAVA remodelling, using a prosthetic ring, on mid-term clinical and echocardiographic-RESULTS:-after aortic valve repair. METHODS: Since February 2003, 250 patients with tricuspid aortic valve insufficiency (AI) underwent aortic valve repair. FAVA dilatation was treated by prosthetic ring in 52 patients, by isolated subcommissural plasty in 62, by subcommissural plasty plus ascending aortic replacement in 57 and by David's reimplantation procedure in 79. Survival rate and…
Polyandry enhances offspring survival in an infanticidal species
2009
The adaptive significance of polyandry is an intensely debated subject in sexual selection. For species with male infanticidal behaviour, it has been hypothesized that polyandry evolved as female counterstrategy to offspring loss: by mating with multiple males, females may conceal paternity and so prevent males from killing putative offspring. Here we present, to our knowledge, the first empirical test of this hypothesis in a combined laboratory and field study, and show that multiple mating seems to reduce the risk of infanticide in female bank voles Myodes glareolus . Our findings thus indicate that females of species with non-resource based mating systems, in which males provide nothing…
Immune activation rapidly mirrored in a secondary sexual trait.
2003
A crucial assumption underlying most models of sexual selection is that sexual advertisements honestly reflect the phenotypic and/or genetic quality of their bearers ([1][1]). Here we show that experimental activation of the immune system is rapidly mirrored in the expression of a carotenoid-based
MALE COURTSHIP SONG AND FEMALE PREFERENCE VARIATION BETWEEN PHYLOGEOGRAPHICALLY DISTINCT POPULATIONS OF DROSOPHILA MONTANA
2007
Understanding the variation within and between populations in important male mating traits and female preferences is crucial to theories concerning the origin of sexual isolation by coevolution or other processes. There have been surprisingly few studies on the extent of variation and covariation within and between populations, especially where the evolutionary relationships between populations are understood. Here we examine variation in female preferences and a sexually selected male song trait, the carrier frequency of the song, within and between populations from different phylogeographic clusters of Drosophila montana. Song is obligatory for successful mating in this species, and both …
Clinical outcomes of fractional flow reserve by computed tomographic angiography-guided diagnostic strategies vs. usual care in patients with suspect…
2015
International audience; AIMS: In symptomatic patients with suspected coronary artery disease (CAD), computed tomographic angiography (CTA) improves patient selection for invasive coronary angiography (ICA) compared with functional testing. The impact of measuring fractional flow reserve by CTA (FFRCT) is unknown. METHODS AND RESULTS: At 11 sites, 584 patients with new onset chest pain were prospectively assigned to receive either usual testing (n = 287) or CTA/FFR(CT) (n = 297). Test interpretation and care decisions were made by the clinical care team. The primary endpoint was the percentage of those with planned ICA in whom no significant obstructive CAD (no stenosis \textgreater/=50% by …
Comparative selection signature analyses identify genomic footprints in Reggiana cattle, the traditional breed of the Parmigiano-Reggiano cheese prod…
2020
Reggiana is an autochthonous cattle breed reared mainly in the province of Reggio Emilia, located in the North of Italy. Reggiana cattle (originally a triple-purpose population largely diffused in the North of Italy) are characterised by a typical solid red coat colour. About 2500 cows of this breed are currently registered to its herd book. Reggiana is now considered a dual-purpose breed even if it is almost completely dedicated to the production of a mono-breed branded Protected Designation of Origin Parmigiano-Reggiano cheese, which is the main driver of the sustainable conservation of this local genetic resource. In this study, we provided the first overview of genomic footprints that c…
Cuticular hydrocarbons of Drosophila montana: geographic variation, sexual dimorphism and potential roles as pheromones.
2014
Abstract Sexual selection within populations can play an important role in speciation when divergence in mating signals and their corresponding preferences occur along different coevolutionary trajectories in different populations. In insects, one potential target of sexual selection is the blend of cuticular hydrocarbons (CHCs), which often show intra- and interspecific variation, sexual dimorphism and may act as pheromones. In Drosophila montana, a cold-adapted, circumboreal member of the Drosophila virilis species group, flies from different populations have been found to show significant premating isolation as well as variation in male mating signal (song) and female preference. While t…