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Anders Pape Moller – 1st expert on this subject based on the ideXlab platform
Host escape behavior and Blood Parasite infections in birdsBehavioral Ecology, 2014Co-Authors: Luz García-longoria, László Zsolt Garamszegi, Anders Pape MollerAbstract:
Active and risk-taking behavior may bring animals into contact with predators but can also result in frequent encounters with Parasites and vectors via the exploration of risky or diverse habitats. Therefore, we predicted that antipredator behavior, here measured as escape behavior when captured by a human, would correlate with risk of Parasite infection at the interspecific level with bolder species having more Parasites than risk-averse species. Here we tested whether species with more active escape behavior also tended to have high prevalence of Blood Parasites, specifically hemosporidian Parasites. Focusing on effect sizes we found that escape behavior was intermediately and positively related to prevalence of infection with Haemoproteus and Leucocytozoon, whereas that was not the case for the more virulent Plasmodium. Species that were habitat generalists and hence encountered a greater diversity of habitats had higher prevalence of Blood Parasites than specialists. In addition, some components of escape behavior were correlated at an intermediate magnitude with habitat exploration, as reflected by the relative frequency of feeding innovations, and coloniality. We failed to find considerable patterns of correlations between most of the behavioral variables and flight initiation distance, another commonly used antipredator behavior. Therefore, behavioral responses to an approaching predator and to being caught by a human likely represent 2 independent axes of antipredator behavior that do not evolve in concert. These findings are consistent with the hypothesis that escape behavior is related to risk of infection with Blood Parasites partially mediated by the effect of habitat generalism.
host ecology and life history traits associated with Blood Parasite species richness in birdsJournal of Evolutionary Biology, 2008Co-Authors: Elena Arriero, Anders Pape MollerAbstract:
Identifying host traits associated with the number of different Parasite species or strains harboured by a particular host species can have important implications for understanding the impact of parasitism on hosts. We investigated associations between host ecology and life history, and Parasite richness and prevalence of the four major avian Blood Parasite genera. We used an extensive data on Blood Parasite infections and host ecology in 263 bird species from the Western Palearctic, combining species-specific data with a comparative approach to control for similarity in phenotype among host species due to the effects of common phylogenetic descent. Adult survival rate negatively correlated with the number of Parasite species infecting a host species when controlling for similarity due to common descent and body mass. In addition, the prevalence of Haemoproteus, Plasmodium and Leucocytozoon was higher in species harbouring a richer Parasite assemblage. These results suggest that the impact on host fitness caused by avian haematozoa may be underestimated in natural populations if the exacerbated virulence associated with exposure to multiple Parasites is not taken into account.
malarial Parasites decrease reproductive success an experimental study in a passerine birdOecologia, 2005Co-Authors: Alfonso Marzal, Carlos Navarro, Florentino De Lope, Anders Pape MollerAbstract:
Malarial Parasites are supposed to have strong negative fitness consequences for their hosts, but relatively little evidence supports this claim due to the difficulty of experimentally testing this. We experimentally reduced levels of infection with the Blood Parasite Haemoproteus prognei in its host the house martin Delichon urbica, by randomly treating adults with primaquine or a control treatment. Treated birds had significantly fewer Parasites than controls. The primaquine treatment increased clutch size by 18%; hatching was 39% higher and fledging 42% higher. There were no effects of treatment on quality of offspring, measured in terms of tarsus length, body mass, haematocrit or T-cell-mediated immune response. These findings demonstrate that malarial Parasites can have dramatic effects on clutch size and other demographic variables, potentially influencing the evolution of clutch size, but also the population dynamics of heavily infected populations of birds.
Juan Moreno – 2nd expert on this subject based on the ideXlab platform
the Blood Parasite haemoproteus reduces survival in a wild bird a medication experimentBiology Letters, 2010Co-Authors: Josue Martinezde La Puente, Juan Moreno, Santiago Merino, Elisa Lobato, Judith Morales, Gustavo Tomas, Sonia Garciafraile, Eduardo J BeldaAbstract:
While avian chronic haemoParasite infections induce reproductive costs, infection has not previously been shown to affect survival. Here, we experimentally reduced, through medication, the intensit…
Carotenoid-based plumage colouration is associated with Blood Parasite richness and stress protein levels in blue tits (Cyanistes caeruleus)Oecologia, 2010Co-Authors: Sara Cerro, Santiago Merino, Josué Martínez-de La Puente, Elisa Lobato, Rafael Ruiz-de-castañeda, Juan Rivero-de Aguilar, Javier Martínez, Judith Morales, Gustavo Tomas, Juan MorenoAbstract:
Carotenoids are molecules that birds are not able to synthesize and therefore, must be acquired through their diet. These pigments, besides their function of giving birds red and yellow colouration when deposited in feathers, seem to act as immune-stimulators and antioxidants in the organism. Hence, only the healthiest individuals would be able to express carotenoid-based ornaments to a larger extent without compromising the physiological functions of carotenoids. Various studies have reported that birds infected by Parasites are paler than those uninfected, but, to our knowledge, none of them has assessed the possible effect of multiple infections by Blood Parasites on plumage colour. By comparing the yellow colour in the breast plumage of blue tits, Cyanistes caeruleus , between birds infected by different numbers of Blood Parasite genera, we found that those birds infected by more than one genus were paler than those parasitized just by one. In addition, we examined the potential role of carotenoid-based plumage colour of blue tits as a long-term indicator of other parameters of health status, such as body condition and immunoglobulin and heat shock protein (HSP) levels. Our results indicate that more brightly coloured birds had lower HSP70 levels than paler birds, but we did not find any significant association between colour and body condition or immunoglobulin levels. In addition, we found a positive significant association between Haemoproteus density of infection and HSP60 levels. Overall, these results support the role of carotenoid-based colours as indicators of health status in blue tits and show detrimental effects of parasitism on this character.
Are avian Blood Parasites pathogenic in the wild? A medication experiment in blue tits (Parus caeruleus).Proceedings of The Royal Society B: Biological Sciences, 2000Co-Authors: Santiago Merino, Juan Moreno, Juan José Sanz, Elena ArrieroAbstract:
The Hamilton and Zuk hypothesis on haemoParasite-mediated sexual selection and certain studies of reproductive costs are based on the assumption that avian Blood Parasite infections are detrimental to their hosts. However, there is no experimental evidence demonstrating harmful effects of Blood Parasites on fitness in wild populations, it even having been suggested that they may be non-pathogenic. Only an experimental manipulation of natural Blood Parasite loads may reveal their harmful effects. In this field experiment we reduced through medication the intensity of infection by Haemoproteus majoris and the prevalence of infection by Leucocytoazoon majoris in blue tits (Parus caeruleus), and demonstrated detrimental effects of natural levels of infection by these common Parasite species on host reproductive success and condition. The fact that some of the costs of infection were paid by offspring indicates that Blood Parasites reduce parental working capacity while feeding nestlings. Medicated females may be able to devote more resources to parental care through being released from the drain imposed upon them by Parasites and/or through a reduced allocation to an immune response. Therefore, this work adds support to previous findings relating hosts’ life-history traits and haematozoan infections.
Orsolya Molnár – 3rd expert on this subject based on the ideXlab platform
Effects of energy and thermoregulation time on physiological state and sexual signal in a lizardJournal of Experimental Zoology, 2020Co-Authors: Boglárka Mészáros, Gábor Herczeg, Katalin Bajer, János Török, Orsolya MolnárAbstract:
: Theory of sexual selection states that males often develop showy signals, which reduce their survival but increase their reproductive success. During mate choice, these conspicuous signals can be honest indicators of individual quality conveying information about the signaler’s physiological state. Sexually selected signals are influenced by many environmental factors; however, whether signals and physiological state are affected together is rarely studied. The ultraviolet-blue throat color of male Lacerta viridis is an intra- and intersexually selected signal connected to Blood Parasite infection and influenced by environmental factors. The aim of this study was to experimentally investigate how ecologically relevant environmental factors affect color signal intensity and key physiological traits parallel. During the mating season, we exposed 40 adult male lizards infected with Blood Parasites to food and basking time treatments in a full factorial design. We measured color, amount of reactive oxygen metabolites (ROMs), hematocrit, immunocompetence, and Blood Parasite intensity before and after treatments. High basking time resulted in elevated immunocompetence coupled with increased ROMs. The high food treatment increased nuptial color brightness, but also increased ROMs and decreased immunocompetence. In summary, our study provides experimental evidence about environmentally induced parallel changes in an honest sexual signal and several quality-indicator physiological traits. We showed that available energy and time for high metabolism have independent and sometimes opposite effects on individual state.
Negative correlation between nuptial throat colour and Blood Parasite load in male European green lizards supports the Hamilton–Zuk hypothesisNaturwissenschaften, 2013Co-Authors: Orsolya Molnár, Boglárka Mészáros, Katalin Bajer, János Török, Gábor HerczegAbstract:
During female mate choice, conspicuous male sexual signals are used to infer male quality and choose the best sire for the offspring. The theory of Parasite-mediated sexual selection (Hamilton–Zuk hypothesis) presumes that Parasite infection can influence the elaboration of sexual signals: resistant individuals can invest more energy into signal expression and thus advertise their individual quality through signal intensity. By preferring these males, females can provide resistance genes for their offspring. Previous research showed that nuptial throat colour of male European green lizard, Lacerta viridis , plays a role in both inter- and intrasexual selections as a condition-dependent multiple signalling system. The aim of this study was to test the predictions of the Hamilton–Zuk hypothesis on male European green lizards. By Blood sampling 30 adult males during the reproductive season, we found members of the Haemogregarinidae family in all but one individual (prevalence = 96 %). The infection intensity showed strong negative correlation with the throat and belly colour brightness in line with the predictions of the Hamilton–Zuk hypothesis. In addition, we found other correlations between infection intensity and other fitness-related traits, suggesting that Parasite load has a remarkable effect on individual fitness. This study shows that throat patch colour of the European green lizards not only is a multiple signalling system but also possibly acts as an honest sexual signal of health state in accordance with the Hamilton–Zuk hypothesis.