Silver-spoon upbringing improves early-life fitness but promotes reproductive ageing in a wild bird

Early-life conditions can have long-lasting effects and organisms that experience a poor start in life are often expected to age at a faster rate. Alternatively, individuals raised in high-quality environments can overinvest in early-reproduction resulting in rapid ageing. Here we use a long-term experimental manipulation of early-life conditions in a natural population of collared flycatchers (Ficedula albicollis), to show that females raised in a low-competition environment (artificially reduced broods) have higher early-life reproduction but lower late-life reproduction than females raised in high-competition environment (artificially increased broods). Reproductive success of high-competition females peaked in late-life, when low-competition females were already in steep reproductive decline and suffered from a higher mortality rate. Our results demonstrate that ‘silver-spoon’ natal conditions increase female early-life performance at the cost of faster reproductive ageing and increased late-life mortality. These findings demonstrate experimentally that natal environment shapes individual variation in reproductive and actuarial ageing in nature

Quantitative Genetics of the Aging of Reproductive Traits in the Houbara Bustard

International audienceDo all traits within an organism age for the same reason? Evolutionary theories of aging share a common assumption: the strength of natural selection declines with age. A corollary is that additive genetic variance should increase with age. However, not all senescent traits display such increases suggesting that other mechanisms may be at play. Using longitudinal data collected from more than 5400 houbara bustards (Chlamydotis undulata) with an exhaustive recorded pedigree, we investigated the genetics of aging in one female reproductive trait (egg production) and three male reproductive traits (courtship display rate, ejaculate size and sperm viability), that display senescence at the phenotypic level. Animal models revealed an increase in additive genetic variance with age for courtship display rate and egg production but an unexpected absence of increased additive genetic variance for ejaculate size and no additive genetic variance for sperm viability. Our results suggest that the mechanisms behind the senescence of some traits are linked with a change in genetic expression, whereas for some other traits, aging may result from the constraints associated with physiological wear and tear on the organism throughout the life of the individual

A global database for metacommunity ecology, integrating species, traits, environment and space

The use of functional information in the form of species traits plays an important role in explaining biodiversity patterns and responses to environmental changes. Although relationships between species composition, their traits, and the environment have been extensively studied on a case-by-case basis, results are variable, and it remains unclear how generalizable these relationships are across ecosystems, taxa and spatial scales. To address this gap, we collated 80 datasets from trait-based studies into a global database for metaCommunity Ecology: Species, Traits, Environment and Space; “CESTES”. Each dataset includes four matrices: species community abundances or presences/absences across multiple sites, species trait information, environmental variables and spatial coordinates of the sampling sites. The CESTES database is a live database: it will be maintained and expanded in the future as new datasets become available. By its harmonized structure, and the diversity of ecosystem types, taxonomic groups, and spatial scales it covers, the CESTES database provides an important opportunity for synthetic trait-based research in community ecology

Tachycardies atriales de l'enfant à coeur sain (à propos de douze cas)

TOURS-BU Médecine (372612103) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Identification of two major genes affecting prolificacy in the French Noire du Velay sheep

Identification of two major genes affecting prolificacy in the French Noire du Velay sheep. 36. Conference of the International Society for Animal Genetics (ISAG

Actuarial senescence can increase the risk of extinction of mammal populations

International audienceDespite recent acknowledgement that senescence can have negative impact on survival and fertility in natural environments across a wide range of animal species, we still do not know if it can reduce the viability of wild endangered populations. Focusing on actuarial senescence (i.e., the decline of survival probabilities at old ages), we use species-specific demographic information to project the extinction risk of wild populations of 58 species of mammals, accounting (or not) for senescence. Our projections reveal potential negative effects of aging on population viability, with an average decrease of 27% of the time to extinction and a potential deterioration of the population-level projected conservation status in 10% of the species. Senescence is associated with particularly strong increases of the extinction risk in species with low mortality rates and long intervals between litters, independently of their place in the phylogeny, indicating that the pace of life history can be used to forecast the detrimental effects of aging on the viability of species. The aim of the various existing systems of classification of threatened species is to set conservation priorities based on assessments of extinction risk. Our results indicate that the quantitative effects of senescence on extinction are highly heterogeneous, which can affect the ranking of species and populations when setting conservation priorities. In mammals, based on life history traits of a few species, generic patterns of senescence can be incorporated into projection population models to minimize these biases in viability assessments

Relationship between circulating AMH and puberty, fertility and prolificacy of small ruminants

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Inter-annual and inter-individual variations in survival exhibit strong seasonality in a hibernating rodent

International audienceMost research on the demography of wild animal populations has focused on characterizing the variation in the mortality of organisms as a function of intrinsic and environmental characteristics. However, such variation in mortality is difficult to relate to functional life history components (e.g. reproduction, dispersal, hibernation) due to the difficulty in monitoring biological processes at a sufficiently fine timescale. In this study, we used a 10-year individual-based data set with an infra-annual timescale to investigate both intra- and inter-annual survival patterns according to intrinsic and environmental covariates in an introduced population of a small hibernating rodent, the Siberian chipmunk. We compared three distinct periods related to particular life history events: spring reproduction, summer reproduction and hibernation. Our results revealed strong interactions between intrinsic and temporal effects. First, survival of male chipmunks strongly decreases during the reproduction periods, while survival is high and equal between sexes during hibernation. Second, the season of birth affects the survival of juveniles during their first hibernation, which does not have long-lasting consequences at the adult stage. Third, at an inter-annual scale, we found that high food resource availability before hibernation and low chipmunk densities specifically favour subsequent winter survival. Overall, our results confirm that the well-known patterns of yearly and inter-individual variation of mortality observed in animals are themselves strongly variable within a given year, suggesting that they are associated with various functional components of the animals’ life history

Age-related variation and temporal patterns in the survival of a long-lived scavenger

International audienceAlthough senescence has been described for various fi tness components in a wide range of animal species, few studies havestudied senescence in long-lived species, and little is known about its interactions with varying environmental conditions.Using a 32 year capture – mark – recapture dataset on the griff on vulture Gyps fulvus , we examined the demographic patternsof actuarial senescence and the patterns of year-to-year variation in survival rates. We found a signifi cant, surprisingly late,decrease of annual survival probabilities from the age of 28 years onward and divided individual lifetimes into to threecategories (juvenile, mid-age and senescent birds). In agreement with the environmental canalization hypothesis, our analysesuncovered 1) higher temporal variation of annual survival probabilities in both the juvenile and senescent age classescompared to the mid-age class and 2) low sensitivity of the population growth rate to the survival of both the juvenile andsenescent age classes. Our results further suggested that the temporal variation in the survival of senescent birds might berelated to intra-annual changes in air temperature amplitudes. Finally, using population dynamics modeling, we revealedcontrasting eff ects of the inclusion of the senescent age class on predicted population growth, depending on how survivalrates were modeled. Altogether, our results demonstrate the existence of a class of senescent birds that exhibit distinctdemographic properties compared to juvenile and mid-age classes

Presence of causative mutations affecting prolificacy in the Noire du Velay and Mouton Vendéen sheep breeds

For many decades, prolificacy has been selected in meat sheep breeds as a polygenic trait but with limited genetic gain. However, the discovery of major genes affecting prolificacy has changed the way of selection for some ovine breeds implementing gene-assisted selection as in the French Lacaune and Grivette meat breeds, or in the Spanish Rasa Aragonesa breed. Based on statistical analysis of litter size parameters from 34 French meat sheep populations, we suspected the segregation of a mutation in a major gene affecting prolificacy in the Noire du Velay and in the Mouton Vendeen breeds exhibiting a very high variability of the litter size. After the genotyping of mutations known to be present in French sheep breeds, we discovered the segregation of the FecL(L) mutation at the B4GALNT2 locus and the FecX(Gr) mutation at the BMP15 locus in Noire du Velay and Mouton Vendeen, respectively. The frequency of ewes carrying FecL(L) in the Noire du Velay population was estimated at 21.2% and the Mouton Vendeen ewes carrying FecX(Gr) at 10.3%. The estimated mutated allele effect of FecL(L) and FecX(Gr) on litter size at + 0.4 and + 0.3 lamb per lambing in Noire du Velay and Mouton Vendeen, respectively. Due to the fairly high frequency and the rather strong effect of the FecL(L) and FecX(Gr) prolific alleles, specific management programmes including genotyping should be implemented for a breeding objective of prolificacy adapted to each of these breeds