Early developmental conditions affect stress response in juvenile but not in adult house sparrows (Passer domesticus).

6 pages; International audience; The short- and long-term consequences of developmental conditions on fitness have received growing attention because the environmental conditions during early life may influence growth, condition at independence, recruitment, reproductive success or survival. We tested here, in a natural house sparrow population, if early conditions during nestling stage affected the stress response of the birds (i) shortly after fledging and (ii) next year, during their first breeding. We experimentally manipulated brood size to mimic different rearing conditions, creating reduced (-2 chicks) and enlarged broods (+2 chicks), while in a third group brood size was not manipul…

Predictions of avian Plasmodium expansion under climate change.

International audience; Vector-borne diseases are particularly responsive to changing environmental conditions. Diurnal temperature variation has been identified as a particularly important factor for the development of malaria parasites within vectors. Here, we conducted a survey across France, screening populations of the house sparrow (Passer domesticus) for malaria (Plasmodium relictum). We investigated whether variation in remotely-sensed environmental variables accounted for the spatial variation observed in prevalence and parasitemia. While prevalence was highly correlated to diurnal temperature range and other measures of temperature variation, environmental conditions could not pre…

Endocrine correlates of the breeding asynchrony between two Corsican populations of Blue tits (Parus caeruleus)

International audience; Analyses of the development of the reproductive system in seasonally breeding birds in the framework of long-term ecological studies are rare. Here, we present the Wrst results of such a study in two Corsican populations of a European passerine bird, the blue tit (Parus caeruleus). The two study populations occupy diVerent oak habitats and are separated by only 25km. Despite their close proximity, they show a one-month diVerence in onset of egg laying, even after controlling for altitude. This micro-geographic diVerence in breeding date appears adaptive because both study populations raise chicks when food is most plentiful. In our study, males reached their maximum …

Trans-equatorial migration routes, staging sites and wintering areas of a High-Arctic avian predator: the Long-tailed Skua (Stercorarius longicaudus).

The Long-tailed Skua, a small (,300 g) Arctic-breeding predator and seabird, is a functionally very important component of the Arctic vertebrate communities in summer, but little is known about its migration and winter distribution. We used lightlevel geolocators to track the annual movements of eight adult birds breeding in north-east Greenland (n = 3) and Svalbard (n = 5). All birds wintered in the Southern Hemisphere (mean arrival-departure dates on wintering grounds: 24 October-21 March): five along the south-west coast of Africa (0–40uS, 0–15uE), in the productive Benguela upwelling, and three further south (30–40uS, 0–50uE), in an area extending into the south-west Indian Ocean. Diffe…

Demographic responses to oxidative stress and inflammation in the wandering albatross (Diomedea exulans).

12 pages; International audience; One of the major challenges in ecological research is the elucidation of physiological mechanisms that underlie the demographic traits of wild animals. We have assessed whether a marker of plasma oxidative stress (TBARS) and plasma haptoglobin (protein of the acute inflammatory phase response) measured at time t predict five demographic parameters (survival rate, return rate to the breeding colony, breeding probability, hatching and fledging success) in sexually mature wandering albatrosses over the next four years (Diomedea exulans) using a five-year individual-based dataset. Non-breeder males, but not females, having higher TBARS at time t had reduced fut…

Accumulation and effects of Cd, Pb and Zn in blackbirds (Turdus merula) along a heavy metal pollution gradient.

Diversifying selection on MHC class I in the house sparrow (Passer domesticus).

10 pages; International audience; Genes of the major histocompatibility complex (MHC) are the most polymorphic loci known in vertebrates. Two main hypotheses have been put forward to explain the maintenance of MHC diversity: pathogen-mediated selection and MHC-based mate choice. Host-parasite interactions can maintain MHC diversity via frequency-dependent selection, heterozygote advantage, and diversifying selection (spatially and/or temporally heterogeneous selection). In this study, we wished to investigate the nature of selection acting on the MHC class I across spatially structured populations of house sparrows (Passer domesticus) in France. To infer the nature of the selection, we comp…

Competition for resources modulates cell-mediated immunity and stress hormone level in nestling collared doves (Streptopelia decaocto)

International audience; Competitive stress imposed by hatching asynchrony may affect developmental trajectories of offsprings by regulating resource allocation between growth and other fitness-related traits. For instance, the down-regulation of immunity is a commonly observed phenomenon under stressful conditions. However, physiological mechanisms that regulate resources allocation to growth and immune functions in response to competition for resources, as well as inter-sexual differences in physiological strategies, are still poorly investigated. To partially fill this gap, we first conducted a descriptive study on chicks of the collared dove (Streptopelia decaocto), a species producing t…

Biodisponibilité et transfert d'éléments traces métalliques dans les réseaux trophiques terrestres.

National audience

An experimental manipulation of life-history trajectories and resistance to oxidative stress

Optimal investment into life-history traits depends on the environmental conditions that organisms are likely to experience during their life. Evolutionary theory tells us that optimal investment in reproduction versus maintenance is likely to shape the pattern of age-associated decline in performance, also known as aging. The currency that is traded against different vital functions is, however, still debated. Here, we took advantage of a phenotypic manipulation of individual quality in early life to explore (1) long-term consequences on life-history trajectories, and (2) the possible physiological mechanism underlying the life-history adjustments. We manipulated phenotypic quality of a co…

Assessing the Cost of Mounting an Immune Response

International audience; The evolution of parasite resistance has often been assumed to be governed by antagonistic selection pressures. Defense against pathogens, by mounting an immune response, confers evident benefits but may also incur costs, so that the optimal level of defense is expected to depend on the balance between benefits and costs. Although the benefits of immune surveillance are well known, estimates of costs are still equivocal. Here we studied the behavioral and physiological modifications associated with exposure to a onreplicating antigen (lipopolysaccharide [LPS] of Escherichia coli) in a passerine species, the house sparrow (Passer domesticus).We further investigated wh…

Multispecies tracking reveals a major seabird hotspot in the North Atlantic

The conservation of migratory marine species, including pelagic seabirds, is challenging because their movements span vast distances frequently beyond national jurisdictions. Here, we aim to identify important aggregations of seabirds in the North Atlantic to inform ongoing regional conservation efforts. Using tracking, phenology, and population data, we mapped the abundance and diversity of 21 seabird species. This revealed a major hotspot associated with a discrete area of the subpolar frontal zone, used annually by 2.9–5 million seabirds from ≥56 colonies in the Atlantic: the first time this magnitude of seabird concentrations has been documented in the high seas. The hotspot is temporal…

Multiple aspects of plasticity in clutch size vary among populations of a globally-distributed songbird.

Plasticity in life-history characteristics can influence many ecological and evolutionary phenomena, including how invading organisms cope with novel conditions in new locations or how environmental change affects organisms in native locations. Variation in reaction norm attributes is a critical element to understanding plasticity in life history, yet we know relatively little about the ways in which reaction norms vary within and among populations. We amassed data on clutch size from marked females in eight populations of house sparrows (Passer domesticus) from North America and Europe. We exploited repeated measures of clutch size to assess both the extent of within-individual phenotypic …

Plasmodium relictum infection and MHC diversity in the house sparrow (Passer domesticus).

Antagonistic coevolution between hosts and parasites has been proposed as a mechanism maintaining genetic diversity in both host and parasite populations. In particular, the high level of genetic diversity usually observed at the major histocompatibility complex (MHC) is generally thought to be maintained by parasite-driven selection. Among the possible ways through which parasites can maintain MHC diversity, diversifying selection has received relatively less attention. This hypothesis is based on the idea that parasites exert spatially variable selection pressures because of heterogeneity in parasite genetic structure, abundance or virulence. Variable selection pressures should select for…

Seabird migration strategies: Flight budgets, diel activity patterns and lunar influence

Every year, billions of birds undertake extensive migrations between breeding and nonbreeding areas, facing challenges that require behavioural adjustments, particularly to flight timing and duration. Such adjustments in daily activity patterns and the influence of extrinsic factors (e.g., environmental conditions, moonlight) have received much more research attention in terrestrial than marine migrants. Taking advantage of the widespread deployment in recent decades of combined light-level geolocator-immersion loggers, we investigated diel organisation and influence of the moon on flight activities during the non-breeding season of 21 migrant seabird species from a wide taxonomic range (6 …

Male bill colour and age are associated with parental abilities and breeding performance in blackbirds

9 pages; International audience; In monogamous bird species, male parental investment may influence offspring fitness and females may gain advantages through mating with males providing extensive paternal care. However, paternal care is a benefit that can only be assessed indirectly because mate choice precedes paternal activities. Individual quality and age, both signalled by morphological characteristics, may reflect parental abilities. Because they may reflect individual foraging abilities, carotenoid-based colorations have been proposed to honestly signal parental quality. The blackbird (Turdus merula), a socially monogamous species, exhibits biparental care and males show bills that va…

Condition-dependent effects of corticosterone on a carotenoid-based begging signal in house sparrows

International audience; Begging is a complex display involving a variety of different visual and auditory signals. Parents are thought to use these signals to adjust their investment in food provisioning. The mechanisms that ensure the honesty of begging displays as indicators of need have been recently investigated. It has been shown that levels of corticosterone (Cort), the hormone released during the stress response, increase during food shortage and are associated with an increased begging rate. In a recent study in house sparrows, although exogenous Cort increased begging rate, parents did not accordingly adjust their provisioning rate. Here, we tested the hypothesis that Cort might af…

Simultaneous pituitary–gonadal recrudescence in two Corsican populations of male blue tits with asynchronous breeding dates

Animal populations living in geographically variable environments respond to different selection pressures. The adaptive character of the responses to environmental information determines the degree of synchrony of the breeding period with local optimal conditions. An example is provided by two populations of Mediterranean blue tits (Parus caeruleus) in Corsica, breeding in different habitats, with a 1-month difference in the onset of egg laying. This difference in the onset of lay is supposed to be adaptive because, although chicks from both populations are raised mostly on caterpillars, the timing of the appearance of caterpillars is earlier for populations of tits associated with deciduo…

EPIDEMIOLOGY OF PLASMODIUM RELICTUM INFECTION IN THE HOUSE SPARROW.

International audience; : Abstract In vertebrates, multiple host characteristics and environmental factors are known to influence infectious disease dynamics. Here, we investigated variability in prevalence and parasitemia of Plasmodium relictum in the house sparrow (Passer domesticus), across a large number of rural and urban populations (n = 16). We found that prevalence was not predicted by any of the host traits investigated (age, sex, body mass or wing length). However, parasitemia was significantly higher in females when compared to males and in 1-yr-olds as compared to older individuals. Neither prevalence nor parasitemia differed according to habitat type (urban vs. rural). These re…

The energetic cost of humoral immunity in the Collared Dove, Streptopelia decaocto : is the magnitude sufficient to force energy-based trade-offs?

International audience; 1. Energy saving is often suggested as the basis of a resource trade-off between immunocompetence and other fitness-relevant traits. This suggests that the energetic cost of an immune response is significant and sufficient to force trade-offs. To date, few studies have investigated the energetic cost of the humoral component of the immune system in birds and furthermore, existing results are contradictory. 2. We addressed this question through two experiments. In experiment 1, the basal metabolic rate (BMR) of Collared Doves, Streptopelia decaocto , challenged with sheep red blood cells (SRBC) was compared with the BMR of control birds. The energetic cost of immunity…

Testosterone and oxidative stress: the oxidation handicap hypothesis

Secondary sexual traits (SST) are usually thought to have evolved as honest signals of individual quality during mate choice. Honesty of SST is guaranteed by the cost of producing/maintaining them. In males, the expression of many SST is testosterone-dependent. The immunocompetence handicap hypothesis has been proposed as a possible mechanism ensuring honesty of SST on the basis that testosterone, in addition to its effect on sexual signals, also has an immunosuppressive effect. The immunocompetence handicap hypothesis has received mixed support. However, the cost of testosterone-based signalling is not limited to immunosuppression and might involve other physiological functions such as the…

Data from: Multiple aspects of plasticity in clutch size vary among populations of a globally distributed songbird

1. Plasticity in life-history characteristics can influence many ecological and evolutionary phenomena, including how invading organisms cope with novel conditions in new locations or how environmental change affects organisms in native locations. Variation in reaction norm attributes is a critical element to understanding plasticity in life history, yet we know relatively little about the ways in which reaction norms vary within and among populations. 2. We amassed data on clutch size from marked females in eight populations of house sparrows (Passer domesticus) from North America and Europe. We exploited repeated measures of clutch size to assess both the extent of within-individual pheno…