The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Jesus M Aviles - One of the best experts on this subject based on the ideXlab platform.
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male spotless Starlings adjust feeding effort based on egg spots revealing ectoparasite load
Animal Behaviour, 2009Co-Authors: Tomas Perezcontreras, Jesus M Aviles, Carlos Navarro, Juan Jose SolerAbstract:Parents may vary their parental behaviour and investment in reproduction in response to parasite-induced changes in the fitness prospects of their offspring. Thus, parents may use the physical condition of their offspring, or any other trait related to parasite load, to adjust parental effort. The immaculate eggs of the spotless Starling, Sturnus unicolor, often become densely spotted owing to the activity of the ectoparasite carnid fly Carnus hemapterus. Spot density anticipates the intensity of fly infestation suffered by nestlings and, therefore, may serve as a cue for parents to adjust reproductive investment. By cleaning spots produced by C. hemapterus on eggs of spotless Starlings, we manipulated the parasite's traces revealing its presence in broods of Starlings, without modifying the level of infestation, to test whether parents use these signals to adjust reproductive effort. We found support for the hypothetical negative effect of Carnus flies since nestlings raised in nests with a higher fly load had lower body mass. The experimental egg cleaning during incubation did not change the intensity of carnid fly infestation during nestling development. However, it had a significant positive influence on paternal but not maternal effort. Our experimental results support the idea that spotless Starling males adjust their effort in response to their perception of the fitness prospects of their nestlings as indirectly estimated by traces of parasites on the eggshells. As far as we know, this is the first evidence of the use of parasite traces to infer risk of parasitic infestation by animal hosts.
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is the relation between colour and immune response mediated by nutritional condition in spotless Starling nestlings
Animal Behaviour, 2007Co-Authors: Juan Jose Soler, Jesus M Aviles, Jose Javier Cuervo, Tomas PerezcontrerasAbstract:The hypothesis that nestling coloration is important for parenteoffspring communication, because it influences parental feeding decisions, has received strong experimental support. In European Starlings, Sturnus vulgaris, and Alpine swifts, Apus melba, manipulation of ultraviolet reflectance of nestlings’ mouth and skin affected the amount of food parents provided, and skin brightness of Starling nestlings predicted their T-cell-mediated immune response. Therefore, a link between nestling coloration and immunity, mediated by parental effort, was suggested. We explored this hypothesis by experimentally feeding some spotless Starling, Sturnus unicolor, nestlings while leaving others in the same nest as a control. First, we found a significant effect of food supplementation on nestlings’ immune response, which is a requirement for the hypothesis. Second, we confirmed in spotless Starlings the association between skin brightness and ability to raise an immune response. However, this correlation disappeared when we controlled for between-nest variation. These results suggest that parental feeding preference is not the only factor explaining nestling immunity, and that covariation between mean brood nestling coloration and parental quality, and/or intrinsic (i.e. genetic) quality of nestlings, may explain the association between immunity and coloration of nestlings. Finally, within-nest variation in nestling coloration partially explained immune responses because food supplementation had more effect on nestlings with brighter skin. We discuss these results as possible evidence of nestling coloration partially reflecting intrinsic characteristics that affect both ability to produce efficient immune responses and parental feeding preferences.
Juan Jose Soler - One of the best experts on this subject based on the ideXlab platform.
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male spotless Starlings adjust feeding effort based on egg spots revealing ectoparasite load
Animal Behaviour, 2009Co-Authors: Tomas Perezcontreras, Jesus M Aviles, Carlos Navarro, Juan Jose SolerAbstract:Parents may vary their parental behaviour and investment in reproduction in response to parasite-induced changes in the fitness prospects of their offspring. Thus, parents may use the physical condition of their offspring, or any other trait related to parasite load, to adjust parental effort. The immaculate eggs of the spotless Starling, Sturnus unicolor, often become densely spotted owing to the activity of the ectoparasite carnid fly Carnus hemapterus. Spot density anticipates the intensity of fly infestation suffered by nestlings and, therefore, may serve as a cue for parents to adjust reproductive investment. By cleaning spots produced by C. hemapterus on eggs of spotless Starlings, we manipulated the parasite's traces revealing its presence in broods of Starlings, without modifying the level of infestation, to test whether parents use these signals to adjust reproductive effort. We found support for the hypothetical negative effect of Carnus flies since nestlings raised in nests with a higher fly load had lower body mass. The experimental egg cleaning during incubation did not change the intensity of carnid fly infestation during nestling development. However, it had a significant positive influence on paternal but not maternal effort. Our experimental results support the idea that spotless Starling males adjust their effort in response to their perception of the fitness prospects of their nestlings as indirectly estimated by traces of parasites on the eggshells. As far as we know, this is the first evidence of the use of parasite traces to infer risk of parasitic infestation by animal hosts.
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is the relation between colour and immune response mediated by nutritional condition in spotless Starling nestlings
Animal Behaviour, 2007Co-Authors: Juan Jose Soler, Jesus M Aviles, Jose Javier Cuervo, Tomas PerezcontrerasAbstract:The hypothesis that nestling coloration is important for parenteoffspring communication, because it influences parental feeding decisions, has received strong experimental support. In European Starlings, Sturnus vulgaris, and Alpine swifts, Apus melba, manipulation of ultraviolet reflectance of nestlings’ mouth and skin affected the amount of food parents provided, and skin brightness of Starling nestlings predicted their T-cell-mediated immune response. Therefore, a link between nestling coloration and immunity, mediated by parental effort, was suggested. We explored this hypothesis by experimentally feeding some spotless Starling, Sturnus unicolor, nestlings while leaving others in the same nest as a control. First, we found a significant effect of food supplementation on nestlings’ immune response, which is a requirement for the hypothesis. Second, we confirmed in spotless Starlings the association between skin brightness and ability to raise an immune response. However, this correlation disappeared when we controlled for between-nest variation. These results suggest that parental feeding preference is not the only factor explaining nestling immunity, and that covariation between mean brood nestling coloration and parental quality, and/or intrinsic (i.e. genetic) quality of nestlings, may explain the association between immunity and coloration of nestlings. Finally, within-nest variation in nestling coloration partially explained immune responses because food supplementation had more effect on nestlings with brighter skin. We discuss these results as possible evidence of nestling coloration partially reflecting intrinsic characteristics that affect both ability to produce efficient immune responses and parental feeding preferences.
Tomas Perezcontreras - One of the best experts on this subject based on the ideXlab platform.
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male spotless Starlings adjust feeding effort based on egg spots revealing ectoparasite load
Animal Behaviour, 2009Co-Authors: Tomas Perezcontreras, Jesus M Aviles, Carlos Navarro, Juan Jose SolerAbstract:Parents may vary their parental behaviour and investment in reproduction in response to parasite-induced changes in the fitness prospects of their offspring. Thus, parents may use the physical condition of their offspring, or any other trait related to parasite load, to adjust parental effort. The immaculate eggs of the spotless Starling, Sturnus unicolor, often become densely spotted owing to the activity of the ectoparasite carnid fly Carnus hemapterus. Spot density anticipates the intensity of fly infestation suffered by nestlings and, therefore, may serve as a cue for parents to adjust reproductive investment. By cleaning spots produced by C. hemapterus on eggs of spotless Starlings, we manipulated the parasite's traces revealing its presence in broods of Starlings, without modifying the level of infestation, to test whether parents use these signals to adjust reproductive effort. We found support for the hypothetical negative effect of Carnus flies since nestlings raised in nests with a higher fly load had lower body mass. The experimental egg cleaning during incubation did not change the intensity of carnid fly infestation during nestling development. However, it had a significant positive influence on paternal but not maternal effort. Our experimental results support the idea that spotless Starling males adjust their effort in response to their perception of the fitness prospects of their nestlings as indirectly estimated by traces of parasites on the eggshells. As far as we know, this is the first evidence of the use of parasite traces to infer risk of parasitic infestation by animal hosts.
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is the relation between colour and immune response mediated by nutritional condition in spotless Starling nestlings
Animal Behaviour, 2007Co-Authors: Juan Jose Soler, Jesus M Aviles, Jose Javier Cuervo, Tomas PerezcontrerasAbstract:The hypothesis that nestling coloration is important for parenteoffspring communication, because it influences parental feeding decisions, has received strong experimental support. In European Starlings, Sturnus vulgaris, and Alpine swifts, Apus melba, manipulation of ultraviolet reflectance of nestlings’ mouth and skin affected the amount of food parents provided, and skin brightness of Starling nestlings predicted their T-cell-mediated immune response. Therefore, a link between nestling coloration and immunity, mediated by parental effort, was suggested. We explored this hypothesis by experimentally feeding some spotless Starling, Sturnus unicolor, nestlings while leaving others in the same nest as a control. First, we found a significant effect of food supplementation on nestlings’ immune response, which is a requirement for the hypothesis. Second, we confirmed in spotless Starlings the association between skin brightness and ability to raise an immune response. However, this correlation disappeared when we controlled for between-nest variation. These results suggest that parental feeding preference is not the only factor explaining nestling immunity, and that covariation between mean brood nestling coloration and parental quality, and/or intrinsic (i.e. genetic) quality of nestlings, may explain the association between immunity and coloration of nestlings. Finally, within-nest variation in nestling coloration partially explained immune responses because food supplementation had more effect on nestlings with brighter skin. We discuss these results as possible evidence of nestling coloration partially reflecting intrinsic characteristics that affect both ability to produce efficient immune responses and parental feeding preferences.
Martin C J Maiden - One of the best experts on this subject based on the ideXlab platform.
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dynamics of campylobacter colonization of a natural host sturnus vulgaris european Starling
Environmental Microbiology, 2009Co-Authors: Frances M Colles, Noel D Mccarthy, J C Howe, C L Devereux, Andrew G Gosler, Martin C J MaidenAbstract:Wild European Starlings (Sturnus vulgaris) shed Campylobacter at high rates, suggesting that they may be a source of human and farm animal infection. A survey of Campylobacter shedding of 957 wild Starlings was undertaken by culture of faecal specimens and genetic analysis of the campylobacters isolated: shedding rates were 30.6% for Campylobacter jejuni, 0.6% for C. coli and 6.3% for C. lari. Genotyping by multilocus sequence typing (MLST) and antigen sequence typing established that these bacteria were distinct from poultry or human disease isolates with the ST-177 and ST-682 clonal complexes possibly representing Starling-adapted genotypes. There was seasonal variation in both shedding rate and genotypic diversity, both exhibiting a maximum during the late spring/early summer. Host age also affected Campylobacter shedding, which was higher in younger birds, and turnover was rapid with no evidence of cross-immunity among Campylobacter species or genotypes. In nestlings, C. jejuni shedding was evident from 9 days of age but siblings were not readily co-infected. The dynamics of Campylobacter infection of Starlings differed from that observed in commercial poultry and consequently there was no evidence that wild Starlings represent a major source of Campylobacter infections of food animals or humans.
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dynamics of campylobacter colonization of a natural host sturnus vulgaris european Starling
Environmental Microbiology, 2009Co-Authors: Frances M Colles, Noel D Mccarthy, J C Howe, C L Devereux, Andrew G Gosler, Martin C J MaidenAbstract:Wild European Starlings (Sturnus vulgaris) shed Campylobacter at high rates, suggesting that they may be a source of human and farm animal infection. A survey of Campylobacter shedding of 957 wild Starlings was undertaken by culture of faecal specimens and genetic analysis of the campylobacters isolated: shedding rates were 30.6% for Campylobacter jejuni, 0.6% for C. coli and 6.3% for C. lari. Genotyping by multilocus sequence typing (MLST) and antigen sequence typing established that these bacteria were distinct from poultry or human disease isolates with the ST-177 and ST-682 clonal complexes possibly representing Starling-adapted genotypes. There was seasonal variation in both shedding rate and genotypic diversity, both exhibiting a maximum during the late spring/early summer. Host age also affected Campylobacter shedding, which was higher in younger birds, and turnover was rapid with no evidence of cross-immunity among Campylobacter species or genotypes. In nestlings, C. jejuni shedding was evident from 9 days of age but siblings were not readily co-infected. The dynamics of Campylobacter infection of Starlings differed from that observed in commercial poultry and consequently there was no evidence that wild Starlings represent a major source of Campylobacter infections of food animals or humans.
C. Charles Michel - One of the best experts on this subject based on the ideXlab platform.
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Understanding and extending the Starling principle
Acta anaesthesiologica Scandinavica, 2020Co-Authors: C. Charles Michel, Thomas E. Woodcock, Fitz Roy E CurryAbstract:The Starling Principle states that fluid movements between blood and tissues are determined by differences in hydrostatic and colloid osmotic (oncotic) pressures between plasma inside microvessels and fluid outside them. The Revised Starling Principle recognizes that, because microvessels are permeable to macromolecules, a balance of pressures cannot halt fluid exchange. In most tissues, steady oncotic pressure differences between plasma and interstitial fluid depend on low levels of steady filtration from plasma to tissues for which the Revised Principle provides the theory. Plasma volume is normally maintained by fluid losses from filtration being matched by fluid gains from lymph. Steady state fluid uptake into plasma only occurs in tissues such as intestinal mucosa and renal peri-tubular capillaries where a protein-free secretion of adjacent epithelia contributes significantly to interstitial fluid volume and keeps interstitial oncotic pressure low. Steady filtration rates in different tissues are disturbed locally by reflex changes in capillary pressure and perfusion. The rapid overall decline in capillary pressure after acute blood loss initiates rapid fluid uptake from tissue to plasma, that is, autotransfusion. Fluid uptake is transient, being rapid at first then attenuating but low levels may continue for more than an hour. The Revised Principle highlights the role of oncotic pressure of small volumes of interstitial fluid within a sub-compartment surrounding the microvessels rather than the tissue's mean interstitial fluid oncotic pressure. This maximizes oncotic pressure differences when capillary pressure are high and enhances initial absorption rates when pressures are low, accelerating short-term regulation of plasma volume.
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Microvascular fluid exchange and the revised Starling principle
Cardiovascular Research, 2010Co-Authors: J. Rodney Levick, C. Charles MichelAbstract:Microvascular fluid exchange (flow J(v)) underlies plasma/interstitial fluid (ISF) balance and oedematous swelling. The traditional form of Starling's principle has to be modified in light of insights into the role of ISF pressures and the recognition of the glycocalyx as the semipermeable layer of endothelium. Sum-of-forces evidence and direct observations show that microvascular absorption is transient in most tissues; slight filtration prevails in the steady state, even in venules. This is due in part to the inverse relation between filtration rate and ISF plasma protein concentration; ISF colloid osmotic pressure (COP) rises as J(v) falls. In some specialized regions (e.g. kidney, intestinal mucosa), fluid absorption is sustained by local epithelial secretions, which flush interstitial plasma proteins into the lymphatic system. The low rate of filtration and lymph formation in most tissues can be explained by standing plasma protein gradients within the intercellular cleft of continuous capillaries (glycocalyx model) and around fenestrations. Narrow breaks in the junctional strands of the cleft create high local outward fluid velocities, which cause a disequilibrium between the subglycocalyx space COP and ISF COP. Recent experiments confirm that the effect of ISF COP on J(v) is much less than predicted by the conventional Starling principle, in agreement with modern models. Using a two-pore system model, we also explore how relatively small increases in large pore numbers dramatically increase J(v) during acute inflammation.
