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Reciprocal positive effects on parasitemia between coinfecting haemosporidian parasites in house sparrows. BMC Ecol Evol 2022; 22:73. [PMID: 35655150 PMCID: PMC9164529 DOI: 10.1186/s12862-022-02026-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 05/23/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Hosts are often simultaneously infected with several parasite species. These co-infections can lead to within-host interactions of parasites, including mutualism and competition, which may affect both virulence and transmission. Birds are frequently co-infected with different haemosporidian parasites, but very little is known about if and how these parasites interact in natural host populations and what consequences there are for the infected hosts. We therefore set out to study Plasmodium and Haemoproteus parasites in house sparrows Passer domesticus with naturally acquired infections using a protocol where the parasitemia (infection intensity) is quantified by qPCR separately for the two parasites. We analysed infection status (presence/absence of the parasite) and parasitemia of parasites in the blood of both adult and juvenile house sparrows repeatedly over the season. RESULTS Haemoproteus passeris and Plasmodium relictum were the two dominating parasite species, found in 99% of the analyzed Sanger sequences. All birds were infected with both Plasmodium and Haemoproteus parasites during the study period. Seasonality explained infection status for both parasites in the adults: H. passeris was completely absent in the winter while P. relictum was present all year round. Among adults infected with H. passeris there was a positive effect of P. relictum parasitemia on H. passeris parasitemia and likewise among adults infected with P. relictum there was a positive effect of H. passeris parasitemia on P. relictum parasitemia. No such associations on parasitemia were seen in juvenile house sparrows. CONCLUSIONS The reciprocal positive relationships in parasitemia between P. relictum and H. passeris in adult house sparrows suggests either mutualistic interactions between these frequently occurring parasites or that there is variation in immune responses among house sparrow individuals, hence some individuals suppress the parasitemia of both parasites whereas other individuals suppress neither. Our detailed screening of haemosporidian parasites over the season shows that co-infections are very frequent in both juvenile and adult house sparrows, and since co-infections often have stronger negative effects on host fitness than the single infection, it is imperative to use screening systems with the ability to detect multiple parasites in ecological studies of host-parasite interactions.
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Albery GF, Morris A, Morris S, Kenyon F, Nussey DH, Pemberton JM. Fitness Costs of Parasites Explain Multiple Life-History Trade-Offs in a Wild Mammal. Am Nat 2021; 197:324-335. [PMID: 33625970 DOI: 10.1086/712633] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractReproduction in wild animals can divert limited resources away from immune defense, resulting in increased parasite burdens. A long-standing prediction of life-history theory states that these parasites can harm the reproductive individual, reducing its subsequent survival and fecundity, producing reproduction-fitness trade-offs. Here, we examined associations among reproductive allocation, immunity, parasitism, and subsequent survival and fecundity in a wild population of individually identified red deer (Cervus elaphus). Using path analysis, we investigated whether costs of lactation in terms of downstream survival and fecundity were mediated by changes in strongyle nematode count and mucosal antibody levels. Lactating females exhibited increased parasite counts, which were in turn associated with substantially decreased fitness in the following year in terms of overwinter survival, fecundity, subsequent calf weight, and parturition date. This study offers observational evidence for parasite regulation of multiple life-history trade-offs, supporting the role of parasites as an important mediating factor in wild mammal populations.
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Holveck MJ, Guerreiro R, Perret P, Doutrelant C, Grégoire A. Eggshell coloration indicates female condition during egg-laying: a field experiment in blue tits. Biol J Linn Soc Lond 2019. [DOI: 10.1093/biolinnean/blz082] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractSeveral selection pressures may explain the evolution of avian eggshell coloration patterns. In cavity-nesting species, there are two main non-exclusive hypotheses. The sexually selected eggshell colour hypothesis proposes that eggshell coloration is a sexually selected signal of female and offspring quality used by males that influences paternal care or future re-mating decisions. The structural function hypothesis proposes that pigments help strengthen the eggshell and are present at higher levels and at the blunt end of the egg when females face calcium shortages. We tested whether eggshell coloration (brown spots on a white ground colour) in blue tits (Cyanistes caeruleus) could reliably indicate female condition at laying by forcing females to produce two consecutive clutches, thus increasing their reproductive costs. Three measures of eggshell coloration – the area covered by spots as well as white ground UV-chroma and brightness – changed between clutches; the fourth measure, spot distribution, did not. The changes were more dramatic in young and lower-quality females. All the measures varied with female quality (i.e. body condition and/or laying date). Overall, higher-quality females produced more colourful (larger, more concentrated spotted surface area; higher UV-chroma) and less bright (i.e. putatively more pigmented) eggshells, a result that is generally in line with past research. We found a clear empirical link between eggshell coloration and female condition in blue tits, an important step in determining whether eggshell coloration is a sexual signal, but which does not exclude a potential concomitant structural function.
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Affiliation(s)
- Marie-Jeanne Holveck
- CEFE UMR 5175, Univ Montpellier, CNRS, Univ Paul Valéry Montpellier 3, EPHE, IRD, Montpellier, France
| | - Romain Guerreiro
- CEFE UMR 5175, Univ Montpellier, CNRS, Univ Paul Valéry Montpellier 3, EPHE, IRD, Montpellier, France
| | - Philippe Perret
- CEFE UMR 5175, CNRS, Univ Montpellier, Univ Paul Valéry Montpellier 3, EPHE, IRD, Montpellier, France
| | - Claire Doutrelant
- CEFE UMR 5175, CNRS, Univ Montpellier, Univ Paul Valéry Montpellier 3, EPHE, IRD, Montpellier, France
| | - Arnaud Grégoire
- CEFE UMR 5175, Univ Montpellier, CNRS, Univ Paul Valéry Montpellier 3, EPHE, IRD, Montpellier, France
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Pigeault R, Cozzarolo CS, Choquet R, Strehler M, Jenkins T, Delhaye J, Bovet L, Wassef J, Glaizot O, Christe P. Haemosporidian infection and co-infection affect host survival and reproduction in wild populations of great tits. Int J Parasitol 2018; 48:1079-1087. [PMID: 30391229 DOI: 10.1016/j.ijpara.2018.06.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 06/06/2018] [Accepted: 06/19/2018] [Indexed: 12/20/2022]
Abstract
Theoretical studies predict that parasitic infection may impact host longevity and ultimately modify the trade-off between reproduction and survival. Indeed, a host may adjust its energy allocation in current reproduction to balance the negative effects of parasitism on its survival prospects. However, very few empirical studies tested this prediction. Avian haemosporidian parasites provide an excellent opportunity to assess the influence of parasitic infection on both host survival and reproduction. They are represented by three main genera (Plasmodium, Haemoproteus and Leucocytozoon) and are highly prevalent in many bird populations. Here we provide the first known long-term field study (12 years) to explore the effects of haemosporidian parasite infection and co-infection on fitness in two populations of great tits (Parus major), using a multistate modeling framework. We found that while co-infection decreased survival probability, both infection and co-infection increased reproductive success. This study provides evidence that co-infections can be more virulent than single infections. It also provides support for the life-history theory which predicts that reproductive effort can be adjusted to balance one's fitness when survival prospects are challenged.
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Affiliation(s)
- R Pigeault
- Département d'Ecologie & Evolution, Lausanne, Switzerland.
| | - C-S Cozzarolo
- Département d'Ecologie & Evolution, Lausanne, Switzerland
| | - R Choquet
- Centre d'Ecologie Fonctionnelle et Evolutive, UMR 5175, Montpellier, France
| | - M Strehler
- Département d'Ecologie & Evolution, Lausanne, Switzerland
| | - T Jenkins
- Département d'Ecologie & Evolution, Lausanne, Switzerland; Musée cantonal de zoologie, Lausanne, Switzerland
| | - J Delhaye
- Département d'Ecologie & Evolution, Lausanne, Switzerland; Evolution et Diversité Biologique, Université Toulouse 3, France
| | - L Bovet
- Département d'Ecologie & Evolution, Lausanne, Switzerland
| | - J Wassef
- Département d'Ecologie & Evolution, Lausanne, Switzerland
| | - O Glaizot
- Musée cantonal de zoologie, Lausanne, Switzerland
| | - P Christe
- Département d'Ecologie & Evolution, Lausanne, Switzerland
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Schoenle LA, Kernbach M, Haussmann MF, Bonier F, Moore IT. An experimental test of the physiological consequences of avian malaria infection. J Anim Ecol 2017; 86:1483-1496. [DOI: 10.1111/1365-2656.12753] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2017] [Accepted: 08/24/2017] [Indexed: 01/03/2023]
Affiliation(s)
| | - Meredith Kernbach
- Department of Biological Sciences Virginia Tech Blacksburg VA USA
- Department of Integrative Biology University of South Florida Tampa FL USA
| | | | - Frances Bonier
- Department of Biological Sciences Virginia Tech Blacksburg VA USA
- Biology Department Queen's University Kingston ON Canada
| | - Ignacio T. Moore
- Department of Biological Sciences Virginia Tech Blacksburg VA USA
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Andreasson F, Nord A, Nilsson JÅ. Brood size constrains the development of endothermy in blue tits. ACTA ACUST UNITED AC 2017; 219:2212-9. [PMID: 27445402 DOI: 10.1242/jeb.135350] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 05/02/2016] [Indexed: 11/20/2022]
Abstract
Altricial birds are unable to maintain body temperature when exposed to low ambient temperatures during the first days after hatching. Thermoregulatory capacity begins to form as postnatal development progresses, and eventually nestlings become homeothermic. Several factors may influence this development at both the level of the individual and the level of the whole brood, but to our knowledge no studies have focused on the effect of brood size per se on the development of endothermy in individual nestlings. We performed cooling experiments on blue tit (Cyanistes caeruleus) nestlings in the field, to study how different experimental brood sizes affected the development of endothermy in individual nestlings and the thermal environment experienced by the whole brood in the nest. Nestlings from all experimental brood sizes showed a decrease in cooling rate as they grew older, but birds from reduced broods showed an earlier onset of endothermy compared with nestlings from enlarged and control broods. This difference manifested during early development and gradually disappeared as nestlings grew older. The thermal environment in the nests differed between treatments during nestling development, such that nest temperature in reduced broods was lower than that in enlarged broods during all days and during nights at the end of the experimental period. We suggest that the development of endothermy in blue tit nestlings is not ontogenetically fixed, but instead may vary according to differences in developmental, nutritional and thermal conditions as determined by brood size.
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Affiliation(s)
- Fredrik Andreasson
- Department of Biology, Section for Evolutionary Ecology, Lund University, Ecology Building, Lund S-223 62, Sweden
| | - Andreas Nord
- Department of Biology, Section for Evolutionary Ecology, Lund University, Ecology Building, Lund S-223 62, Sweden
| | - Jan-Åke Nilsson
- Department of Biology, Section for Evolutionary Ecology, Lund University, Ecology Building, Lund S-223 62, Sweden
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Body Mass, Wing Length, and Condition of Wintering Ducks Relative to Hematozoa Infection. JOURNAL OF FISH AND WILDLIFE MANAGEMENT 2017. [DOI: 10.3996/082016-jfwm-063] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Abstract
Waterfowl managers lack information regarding factors that may be reducing the positive response of waterfowl body condition to habitat improvements. Protozoan blood parasites (i.e., hematozoa) are commonly found in birds and have been related to reduced body mass, wing length, and body condition. We studied relationships between 12 measures of hematozoa infection and body mass, wing length, and body mass divided by wing length (i.e., body condition index) of the five most common duck species (northern pintail [Anas acuta], mallard [A. platyrhynchos], green-winged teal [A. crecca], American wigeon [A. americana], northern shoveler [A. clypeata]) wintering in the Central Valley of California during October 2006–January 2007. After accounting for variation due to species, age–sex cohort, Central Valley region, and month, wing length, body mass, and body condition index were found to be negatively related to infection by Leucocytozoon and by “any hematozoa” but not related to infection by only Plasmodium or Haemoproteus, or coinfections of greater than one genus or parasite haplotype (albeit few ducks had Plasmodium or Haemoproteus infection or coinfections). Evidence of a negative relationship with infection was stronger for body mass and body condition index than for wing length and indicated that the relationships varied among species, age–sex cohorts, regions, and months. Compared with uninfected ducks, hematozoa-infected duck body mass, wing length, and body condition index was −1.63% (85% CI = −2.79% to −0.47%), −0.12% (−0.41% to 0.17%), and −1.38% (−2.49% to −0.26%), respectively. Although seemingly small, the −1.63% difference in body mass represents a large percentage (e.g., 38% for northern pintail) of the observed increase in wintering duck body mass associated with Central Valley habitat improvements. Because infection prevalence and relationship to body condition might change over time because of climate or other factors, tracking hematozoa infection prevalence might be important to inform and accurately assess the effect of conservation programs designed to improve waterfowl body condition.
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Fryxell RTT, Lewis TT, Peace H, Hendricks BBM, Paulsen D. Identification of Avian Malaria (PlasmodiumSp.) and Canine Heartworm (Dirofilaria immitis) in the Mosquitoes of Tennessee. J Parasitol 2014; 100:455-62. [DOI: 10.1645/13-443.1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Hegemann A, Matson KD, Flinks H, Tieleman BI. Offspring pay sooner, parents pay later: experimental manipulation of body mass reveals trade-offs between immune function, reproduction and survival. Front Zool 2013; 10:77. [PMID: 24344978 PMCID: PMC3878409 DOI: 10.1186/1742-9994-10-77] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 12/13/2013] [Indexed: 11/10/2022] Open
Abstract
INTRODUCTION Life-history theory predicts that organisms trade off survival against reproduction. However, the time scales on which various consequences become evident and the physiology mediating the cost of reproduction remain poorly understood. Yet, explaining not only which mechanisms mediate this trade-off, but also how fast or slow the mechanisms act, is crucial for an improved understanding of life-history evolution. We investigated three time scales on which an experimental increase in body mass could affect this trade-off: within broods, within season and between years. We handicapped adult skylarks (Alauda arvensis) by attaching extra weight during first broods to both adults of a pair. We measured body mass, immune function and return rates in these birds. We also measured nest success, feeding rates, diet composition, nestling size, nestling immune function and recruitment rates. RESULTS When nestlings of first broods fledged, parent body condition had not changed, but experimental birds experienced higher nest failure. Depending on the year, immune parameters of nestlings from experimental parents were either higher or lower than of control nestlings. Later, when parents were feeding their second brood, the balance between self-maintenance and nest success had shifted. Control and experimental adults differed in immune function, while mass and immune function of their nestlings did not differ. Although weights were removed after breeding, immune measurements during the second brood had the capacity to predict return rates to the next breeding season. Among birds that returned the next year, body condition and reproductive performance a year after the experiment did not differ between treatment groups. CONCLUSIONS We conclude that the balance between current reproduction and survival shifts from affecting nestlings to affecting parents as the reproductive season progresses. Furthermore, immune function is apparently one physiological mechanism involved in this trade-off. By unravelling a physiological mechanism underlying the trade-offs between current and future reproduction and by demonstrating the different time scales on which it acts, our study represents an important step in understanding a central theory of life-history evolution.
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Affiliation(s)
- Arne Hegemann
- Animal Ecology Group, Centre for Ecological and Evolutionary Studies, University of Groningen, P,O, Box 11103, 9700, CC Groningen, The Netherlands.
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10
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Integrated plumage colour variation in relation to body condition, reproductive investment and laying date in the collared flycatcher. Naturwissenschaften 2013; 100:983-91. [DOI: 10.1007/s00114-013-1099-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 08/30/2013] [Accepted: 09/02/2013] [Indexed: 10/26/2022]
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Murdock CC, Foufopoulos J, Simon CP. A transmission model for the ecology of an avian blood parasite in a temperate ecosystem. PLoS One 2013; 8:e76126. [PMID: 24073288 PMCID: PMC3779181 DOI: 10.1371/journal.pone.0076126] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Accepted: 08/27/2013] [Indexed: 11/18/2022] Open
Abstract
Most of our knowledge about avian haemosporidian parasites comes from the Hawaiian archipelago, where recently introduced Plasmodiumrelictum has contributed to the extinction of many endemic avian species. While the ecology of invasive malaria is reasonably understood, the ecology of endemic haemosporidian infection in mainland systems is poorly understood, even though it is the rule rather than the exception. We develop a mathematical model to explore and identify the ecological factors that most influence transmission of the common avian parasite, Leucocytozoonfringillinarum (Apicomplexa). The model was parameterized from White-crowned Sparrow (Zonotrichialeucophrys) and S. silvestre / craigi black fly populations breeding in an alpine ecosystem. We identify and examine the importance of altricial nestlings, the seasonal relapse of infected birds for parasite persistence across breeding seasons, and potential impacts of seasonal changes in black fly emergence on parasite prevalence in a high elevation temperate system. We also use the model to identify and estimate the parameters most influencing transmission dynamics. Our analysis found that relapse of adult birds and young of the year birds were crucial for parasite persistence across multiple seasons. However, distinguishing between nude nestlings and feathered young of the year was unnecessary. Finally, due to model sensitivity to many black fly parameters, parasite prevalence and sparrow recruitment may be most affected by seasonal changes in environmental temperature driving shifts in black fly emergence and gonotrophic cycles.
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Affiliation(s)
- Courtney C. Murdock
- School of Natural Resources & Program in the Environment, University of Michigan, Ann Arbor, Michigan, United States of America
- Center for Infectious Disease Dynamics, Department of Entomology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Johannes Foufopoulos
- School of Natural Resources & Program in the Environment, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Carl P. Simon
- Ford School of Public Policy & Center for the Study of Complex Systems, Department of Mathematics, University of Michigan, Ann Arbor, Michigan, United States of America
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Westerdahl H, Stjernman M, Råberg L, Lannefors M, Nilsson JÅ. MHC-I affects infection intensity but not infection status with a frequent avian malaria parasite in blue tits. PLoS One 2013; 8:e72647. [PMID: 24023631 PMCID: PMC3758318 DOI: 10.1371/journal.pone.0072647] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 07/12/2013] [Indexed: 12/23/2022] Open
Abstract
Host resistance against parasites depends on three aspects: the ability to prevent, control and clear infections. In vertebrates the immune system consists of innate and adaptive immunity. Innate immunity is particularly important for preventing infection and eradicating established infections at an early stage while adaptive immunity is slow, but powerful, and essential for controlling infection intensities and eventually clearing infections. Major Histocompatibility Complex (MHC) molecules are central in adaptive immunity, and studies on parasite resistance and MHC in wild animals have found effects on both infection intensity (parasite load) and infection status (infected or not). It seems MHC can affect both the ability to control infection intensities and the ability to clear infections. However, these two aspects have rarely been considered simultaneously, and their relative importance in natural populations is therefore unclear. Here we investigate if MHC class I genotype affects infection intensity and infection status with a frequent avian malaria infection Haemoproteus majoris in a natural population of blue tits Cyanistes caeruleus. We found a significant negative association between a single MHC allele and infection intensity but no association with infection status. Blue tits that carry a specific MHC allele seem able to suppress H. majoris infection intensity, while we have no evidence that this allele also has an effect on clearance of the H. majoris infection, a result that is in contrast with some previous studies of MHC and avian malaria. A likely explanation could be that the clearance rate of avian malaria parasites differs between avian malaria lineages and/or between avian hosts.
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Affiliation(s)
| | | | - Lars Råberg
- Department of Biology, Lund University, Lund, Sweden
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13
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Bichet C, Sorci G, Robert A, Julliard R, Lendvai AZ, Chastel O, Garnier S, Loiseau C. Epidemiology of Plasmodium relictum infection in the house sparrow. J Parasitol 2013; 100:59-65. [PMID: 23987473 DOI: 10.1645/12-24.1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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 results suggest that inter-population variation in parasitemia depends on host intrinsic factors whereas variation in prevalence could be due to environmental differences between populations, such as climatic variables that might affect the abundance of vectors. This large-scale study gives us a better understanding of the key factors involved in the epidemiology of avian malaria.
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Affiliation(s)
- Coraline Bichet
- Biogéosciences, CNRS UMR 6282, Université de Bourgogne, 6 Boulevard Gabriel, 21000 Dijon, France
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14
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Astudillo VG, Hernández SM, Kistler WM, Boone SL, Lipp EK, Shrestha S, Yabsley MJ. Spatial, temporal, molecular, and intraspecific differences of haemoparasite infection and relevant selected physiological parameters of wild birds in Georgia, USA. INTERNATIONAL JOURNAL FOR PARASITOLOGY-PARASITES AND WILDLIFE 2013; 2:178-89. [PMID: 24533333 PMCID: PMC3862535 DOI: 10.1016/j.ijppaw.2013.04.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Revised: 04/26/2013] [Accepted: 04/30/2013] [Indexed: 11/30/2022]
Abstract
Variable prevalences of different haemoparasite species noted among passerine hosts. Different foraging guilds associated with different haemoparasite infections. Prevalence of Haemoproteus, Plasmodium, and Trypanosoma higher in breeding season. PCV differences noted between bird species but no effect of haemoparasites on PCV or polychromasia. Novel haplotypes detected and new geographic and host associations noted for seven haplotypes.
The prevalence of five avian haemoparasite groups was examined for effects on health and associations with extrinsic factors. Overall, 786 samples were examined from six sites in two Georgia (USA) watersheds, during breeding and non-breeding periods in 2010 and 2011. Among the four most commonly infected species, Haemoproteus prevalence was significantly higher in Northern Cardinals (Cardinalis cardinalis) compared to Indigo Buntings (Passerina cyanea) and Tufted Titmice (Baeolophus bicolor) while prevalence in White-throated Sparrows (Zonotrichia albicollis) was significantly higher than in Indigo Buntings. Higher prevalence of Plasmodium was noted in Tufted Titmice and Northern Cardinals. While Leucocytozoon prevalence was highest in White-throated Sparrows, Trypanosoma prevalence was highest in Tufted Titmice. Interesting differences in infection probabilities were noted between foraging guilds with Haemoproteus associated with low-middle level strata and birds in the middle-upper strata were more likely to be infected with Plasmodium and Trypanosoma. In contrast, ground-foraging birds were more likely to be infected with Leucocytozoon. Breeding season was correlated with higher polychromasia counts and higher prevalence of Haemoproteus, Plasmodium and Trypanosoma. In addition, prevalence of infection with certain haemoparasite genera and packed cell volume (PCV) were different among host species. Body mass index was inversely correlated with prevalence of microfilaria infection but positively related to Haemoproteus infection. However, we found no relationship between PCV or polychromasia levels with haemoparasite infection. Molecular characterization of 61 samples revealed 19 unique Haemoproteus (n = 7) and Plasmodium (n = 12) haplotypes with numerous new host records. No differences were noted in haplotype diversity among birds with different migratory behaviors or foraging heights, thus additional studies are needed that incorporate molecular analysis, host biology, and vector biology into comprehensive models on parasite ecology. Detailed morphological examination of these parasites is also necessary to determine if closely related haplotypes represent single species or morphologically distinct, but closely related, haplotypes.
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Affiliation(s)
- Viviana González Astudillo
- Daniel B. Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30602, USA
| | - Sonia M Hernández
- Daniel B. Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30602, USA ; Southeastern Cooperative Wildlife Disease Study, Department of Population Health, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
| | - Whitney M Kistler
- Daniel B. Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30602, USA ; Southeastern Cooperative Wildlife Disease Study, Department of Population Health, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
| | - Shaun L Boone
- Daniel B. Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30602, USA
| | - Erin K Lipp
- Department of Environmental Health Science, College of Public Health, University of Georgia, Athens, GA 30602, USA
| | - Sudip Shrestha
- Daniel B. Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30602, USA
| | - Michael J Yabsley
- Daniel B. Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30602, USA ; Southeastern Cooperative Wildlife Disease Study, Department of Population Health, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
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15
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Wutzler R, Foerster K, Kempenaers B. MHC class I variation in a natural blue tit population (Cyanistes caeruleus). Genetica 2012; 140:349-64. [PMID: 23073914 DOI: 10.1007/s10709-012-9679-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Accepted: 09/03/2012] [Indexed: 12/13/2022]
Abstract
The major histocompatibility complex (MHC) is central to the vertebrate immune system and its highly polymorphic genes are considered to influence several life-history traits of individuals. To characterize the MHC in a natural population of blue tits (Cyanistes caeruleus) we investigated the class I exon 3 diversity of more than 900 individuals. We designed two pairs of motif-specific primers that reliably amplify independent subsets of MHC alleles. Applying denaturing gradient gel electrophoresis (DGGE) we obtained 48 independently inherited units of unique band patterns (DGGE-haplogroups), which were validated in a segregation analysis within 105 families. In a second approach, we extensively sequenced 6 unrelated individuals to confirm that DGGE-haplogroup composition reflects individual allelic variation. The highest number of different DGGE-haplogroups in a single individual corresponded in 19 MHC exon 3 sequences, suggesting a minimum of 10 amplified MHC class I loci in the blue tit. In total, we identified 50 unique functional and 3 non-functional sequences. Functional sequences showed high levels of recombination and strong positive selection in the antigen binding region, whereas nucleotide diversity was comparatively low in the range of all passerine species. Finally, in a phylogenetic comparison of passerine MHC class I exon 3 sequences we discuss conflicting evolutionary signals possibly due to recent gene duplication, recombination events and concerted evolution. Our results indicate that the described method is suitable to effectively explore the MHC diversity and its ecological impacts in blue tits in future studies.
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Affiliation(s)
- R Wutzler
- Department of Behavioural Ecology and Evolutionary Genetics, Max Planck Institute for Ornithology, 82305 Seewiesen, Germany.
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16
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Baillie SM, Gudex-Cross D, Barraclough RK, Blanchard W, Brunton DH. Patterns in avian malaria at founder and source populations of an endemic New Zealand passerine. Parasitol Res 2012; 111:2077-89. [PMID: 22875394 DOI: 10.1007/s00436-012-3055-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Accepted: 07/16/2012] [Indexed: 11/25/2022]
Abstract
Significant progress in our understanding of disease transmission in the wild can be made by examining variation in host-parasite-vector interactions after founder events of the host. This study is the first to document patterns in avian malaria, Plasmodium spp., infecting an endemic New Zealand passerine, Anthornis melanura, at multiple-host subpopulations simultaneously. We assess the Beaudoin hypothesis of bimodal seasonality and use AIC model selection to determine host factors associated with disease prevalence. We had the rare opportunity to test the enemy release hypothesis (ERH) after a recent colonisation event of the bellbird host. Four Plasmodium species were found to infect bellbirds. Temporal patterns of three exotic parasite lineages, including GRW06 Plasmodium (Huffia) elongatum, SYAT05 Plasmodium (Novyella) vaughani and a Plasmodium (Haemamoeba) relictum, were sporadic with low prevalence year round. The fourth species was an endemic parasite, an unresolved Plasmodium (Novyella) sp. here called ANME01, which exhibited a strong winter peak at the source subpopulations possibly indicating greater immune stressors at the densely populated source site. At the colonies, we observed bimodal seasonality in the prevalence of ANME01 with autumn and spring peaks. These infection peaks were male-biased, and the amplitude of sex bias was more pronounced at the newer colony perhaps due to increased seasonal competition resulting from territory instability. We observed a decrease in parasite species diversity and increase in body condition from source to founder sites, but statistical differences in the direct relationship between body condition and malaria prevalence between source and colony were weak and significant only during winter. Though our data did not strongly support the ERH, we highlight the benefits of 'conspecific release' associated with decreased population density and food competition. Our findings contribute to the identification of ecological and environmental drivers of variability in malaria transmission, which is valuable for predicting the consequences of both natural range expansions, as well as host re-introductions resulting from intensive conservation practices.
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Affiliation(s)
- Shauna M Baillie
- Institute of Natural Sciences, Massey University, Private Bag 102-904 North Shore Mail Centre, Auckland 0745, New Zealand.
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17
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Nicolaus M, Michler SPM, Ubels R, van der Velde M, Bouwman KM, Both C, Tinbergen JM. Local sex ratio affects the cost of reproduction. J Anim Ecol 2011; 81:564-72. [DOI: 10.1111/j.1365-2656.2011.01933.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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18
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Doutrelant C, Grégoire A, Midamegbe A, Lambrechts M, Perret P. Female plumage coloration is sensitive to the cost of reproduction. An experiment in blue tits. J Anim Ecol 2011; 81:87-96. [PMID: 21819397 DOI: 10.1111/j.1365-2656.2011.01889.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
1. A growing number of studies suggest that female ornaments are linked to maternal quality and influence male mate choice. These findings challenge the traditional male-biased view of sexual selection and the hypothesis that female ornaments are the outcome of a genetic correlation with male ornaments. To further test the hypothesis that female traits have a function, it is now essential to investigate their honesty and to determine how signalling and reproduction interact in females. If female traits are honest indicators of quality, then they are likely to have a specific signalling function. 2. We investigated whether carry-over effects of reproduction might ensure the honesty of plumage colour signalling of a bird species with conspicuous UV-blue and yellow coloration, the blue tit Cyanistes caeruleus. Reproductive effort was manipulated by removing clutches, thereby forcing both sexes to reproduce twice and to raise chicks later in the breeding season when food is less abundant. In the year following this manipulation, we investigated the change in plumage in experimental and control males and females. The change was measured in the two putative feather ornaments, the UV-blue cap and the yellow breast, and another feather trait probably less likely to be sexually selected: the wing length. We also tested whether higher-quality females had their coloration less affected by the experiment. 3. We found that control but not manipulated males and females increased their signal towards UV. In addition, in the manipulated group, females that were able to lay more eggs had their UV-blue coloration less affected by the treatment. For yellow coloration, we found that manipulated yearlings but not manipulated adults decreased their yellow chroma in comparison with control. Lastly, our results show that the condition of the manipulated females tended to be positively correlated with yellow chroma. 4. These results show that the trade-offs between reproduction and signalling can ensure the honesty of conspicuous plumage traits in female and male blue tits. In addition, they suggest that female traits have the potential to evolve under sexual selection in this and other bird species.
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Karell P, Ahola K, Karstinen T, Kolunen H, Siitari H, Brommer JE. Blood parasites mediate morph-specific maintenance costs in a colour polymorphic wild bird. J Evol Biol 2011; 24:1783-92. [PMID: 21599778 DOI: 10.1111/j.1420-9101.2011.02308.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Parasites can mediate profound negative effects on host fitness. Colour polymorphism has been suggested to covary genetically with intrinsic physiological properties. Tawny owl colour polymorphism is highly heritable with two main morphs, grey and brown. We show that experimental medication acts to reduce blood parasites and that medicated grey females maintain body mass during breeding, whereas medicated brown females decline in body mass similar to control females of both morphs. We find no effect of medication on general immunoglobulin levels, antigen-specific humoral response or H/L ratio. In the descriptive data, both morphs have similar blood parasite infection rates, but blood parasite infection is associated with decreased body mass in brown but not in grey females. We conclude that blood parasite infection primarily has somatic costs, which differ between the two highly heritable tawny owl colour morphs with more pronounced costs in the grey (little pigmented) morph than in the brown (heavily pigmented) morph. Because our descriptive results imply the opposite pattern, our findings highlight the need of experimental manipulation when studying heritable variation in hosts' response to parasitism.
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Affiliation(s)
- P Karell
- Bird Ecology Unit, Department of Biosciences, University of Helsinki, Helsinki, Finland.
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20
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Knowles SCL, Wood MJ, Sheldon BC. Context-dependent effects of parental effort on malaria infection in a wild bird population, and their role in reproductive trade-offs. Oecologia 2010; 164:87-97. [PMID: 20625768 DOI: 10.1007/s00442-010-1706-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2009] [Accepted: 06/17/2010] [Indexed: 11/28/2022]
Abstract
Although trade-offs between reproductive effort and other fitness components are frequently documented in wild populations, the underlying physiological mechanisms remain poorly understood. Parasitism has been suggested to mediate reproductive trade-offs, yet only a limited number of parasite taxa have been studied, and reproductive effort-induced changes in parasitism are rarely linked to trade-offs observed in the same population. We conducted a brood size manipulation experiment in blue tits (Cyanistes caeruleus) infected with malaria (Plasmodium) parasites, and used quantitative PCR to measure changes in parasitaemia. In one of two years investigated, parasitaemia increased as a result of brood enlargement, and was also positively associated with two other indicators of reproductive effort: clutch size and single parenthood. These associations between both experimental and naturally varying reproductive effort and parasitaemia suggest that immune control of chronic malaria infections can be compromised when parents are working hard. Brood size manipulation significantly affected the number of independent offspring produced, which was maximised when brood size was unchanged. Moreover, when parents were infected with one of two common Plasmodium species, the shape of this trade-off curve was more pronounced, suggesting that parasitic infection may exacerbate the trade-off between quantity and quality of offspring. Although the involvement of parasites in survival costs of reproduction has received much attention, these results suggest their role in other commonly documented reproductive trade-offs, such as that between number and quality of offspring, warrants further study.
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Affiliation(s)
- Sarah C L Knowles
- Department of Zoology, Edward Grey Institute, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK.
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la Puente JMD, Merino S, Tomás G, Moreno J, Morales J, Lobato E, García-Fraile S, Belda EJ. The blood parasite Haemoproteus reduces survival in a wild bird: a medication experiment. Biol Lett 2010; 6:663-5. [PMID: 20181556 DOI: 10.1098/rsbl.2010.0046] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
While avian chronic haemoparasite infections induce reproductive costs, infection has not previously been shown to affect survival. Here, we experimentally reduced, through medication, the intensity of infection by Haemoproteus parasites in wild-breeding female blue tits Cyanistes caeruleus. However, this treatment did not reduce the intensity of infection in males or the intensity of infection by Leucocytozoon. Medicated females, but not males, showed increased local survival until the next breeding season compared with control birds. To our knowledge, this is the first empirical evidence showing long-term direct survival costs of chronic Haemoproteus infections in wild birds.
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Bourgeon S, Le Maho Y, Raclot T. Proximate and ultimate mechanisms underlying immunosuppression during the incubation fast in female eiders: roles of triiodothyronine and corticosterone. Gen Comp Endocrinol 2009; 163:77-82. [PMID: 19063892 DOI: 10.1016/j.ygcen.2008.11.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2008] [Revised: 11/18/2008] [Accepted: 11/19/2008] [Indexed: 11/24/2022]
Abstract
Available resources being limited, life-history theory predicts that natural selection favours the evolution of physiological mechanisms that ensure their optimal allocation between competing activities. Accordingly, to maximize their selective value, long-lived species face a trade-off between survival and reproduction. Immunity is hypothesized to share limited resources with other physiological functions and this may partly account for the fitness costs of reproduction. However, both ultimate and proximate factors underlying the observed trade-off between reproductive effort and immunocompetence remain poorly documented. Using female common eiders (Somateria mollissima) as a model, it was earlier shown that acquired immunity is negatively affected during the incubation fast, while its activation has a negative impact on females' fitness. The current paper reports data on corticosterone and triiodothyronine manipulations designed to shed more light onto both ultimate and proximate mechanisms involved in the control of immunosuppression in breeding female eiders. It was found that corticosterone is not the main proximate factor responsible for immunosuppression and that the immunosuppressive effects of both hormones may be mediated by their negative effects on body mass. These observations are consistent with the proposed link between the immune system and body fat reserves and, with the resource-limitation hypothesis for stress-induced immunosuppression. However the alternative hypothesis, the immunopathology-avoidance hypothesis cannot be discarded and the two hypotheses are not mutually exclusive in breeding female eiders.
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Affiliation(s)
- Sophie Bourgeon
- Norwegian Institute for Nature Research, The Polar Environmental Centre, NO-9296 Tromsø, Norway.
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Tsuda Y, Matsui S, Saito A, Akatani K, Sato Y, Takagi M, Murata K. Ecological study of avian malaria vectors on the island of Minami-Daito, Japan. JOURNAL OF THE AMERICAN MOSQUITO CONTROL ASSOCIATION 2009; 25:279-284. [PMID: 19852217 DOI: 10.2987/08-5841.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The seasonal prevalence and spatial distribution of mosquitoes were examined as part of an avian malaria study on the oceanic island of Minami-Daito Island, Japan. Because dry ice was not available in this study, yeast-generated CO2 was used to attract biting mosquitoes. Adult mosquitoes were collected biweekly using battery-operated traps enhanced with yeast-generated CO2 and a gravid trap from March 2006 to February 2007. The CO2-baited traps were distributed in 4 different habitats: sugar cane field, forest and vegetation ring, residential area, and swamp area. At 3 collection sites beside sugar cane fields, traps were fixed at 2 different heights (3 and 6 m above the ground). A total of 1,437 mosquitoes of the following 9 species were collected: Culex quinquefasciatus, Aedes albopictus, Coquillettidia sp., Mansonia uniformis, Culex rubithoracis, Armigeres subalbatus, Lutzia fuscanus, Aedes daitensis, and Aedes togoi. Among them, Cx. quinquefasciatus, Ae. albopictus, and Coquillettidia sp. were dominant. The high density and wide distribution of Cx. quinquefasciatus throughout the island suggested the importance of this species as a principal vector of avian malaria on the island.
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Affiliation(s)
- Yoshio Tsuda
- Department of Medical Entomology, National Institute of Infectious Diseases, Toyama, Tokyo, Japan
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Hansson B, Ljungqvist M, Dawson DA, Mueller JC, Olano-Marin J, Ellegren H, Nilsson JÅ. Avian genome evolution: insights from a linkage map of the blue tit (Cyanistes caeruleus). Heredity (Edinb) 2009; 104:67-78. [DOI: 10.1038/hdy.2009.107] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
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Knowles SCL, Nakagawa S, Sheldon BC. Elevated reproductive effort increases blood parasitaemia and decreases immune function in birds: a meta-regression approach. Funct Ecol 2009. [DOI: 10.1111/j.1365-2435.2008.01507.x] [Citation(s) in RCA: 154] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Bears H, Martin K, White GC. Breeding in high-elevation habitat results in shift to slower life-history strategy within a single species. J Anim Ecol 2009; 78:365-75. [DOI: 10.1111/j.1365-2656.2008.01491.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Stjernman M, Råberg L, Nilsson JÅ. Long-term effects of nestling condition on blood parasite resistance in blue tits (Cyanistes caeruleus). CAN J ZOOL 2008. [DOI: 10.1139/z08-071] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Little is know about whether the conditions experienced during ontogeny affect resistance to parasites later in life in wild animals. Here, we used a population of blue tits ( Cyanistes caeruleus (L., 1758)) to investigate to what extent conditions experienced during the nestling stage could explain the ability to control blood parasite ( Haemoproteus majoris (Laveran, 1902)) infections 1 year later. Although short-term effects may be expected based on the well-known sensitivity of the immune system to current conditions, it is less known whether this translates into a permanent alteration of parasite resistance. By relating nestling condition (measured as body mass or size-corrected body mass) at the beginning and end of the nestling stage to parasite intensity of individual recruiting birds 1 year later, we indeed found significant positive effects of both early and late nestling condition on the long-term ability to control parasites. These results indicate that parasites may be important as a mechanistic explanation for the trade-off between number and quality of offspring. It further points to the potential relevance for maternal effects in host–parasite interactions.
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Affiliation(s)
- M. Stjernman
- Department of Animal Ecology, Lund University, Ecology Building, SE-223 62 Lund, Sweden
| | - L. Råberg
- Department of Animal Ecology, Lund University, Ecology Building, SE-223 62 Lund, Sweden
| | - J.-Å. Nilsson
- Department of Animal Ecology, Lund University, Ecology Building, SE-223 62 Lund, Sweden
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Stjernman M, Råberg L, Nilsson JA. Maximum host survival at intermediate parasite infection intensities. PLoS One 2008; 3:e2463. [PMID: 18560544 PMCID: PMC2413421 DOI: 10.1371/journal.pone.0002463] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2008] [Accepted: 05/11/2008] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Although parasitism has been acknowledged as an important selective force in the evolution of host life histories, studies of fitness effects of parasites in wild populations have yielded mixed results. One reason for this may be that most studies only test for a linear relationship between infection intensity and host fitness. If resistance to parasites is costly, however, fitness may be reduced both for hosts with low infection intensities (cost of resistance) and high infection intensities (cost of parasitism), such that individuals with intermediate infection intensities have highest fitness. Under this scenario one would expect a non-linear relationship between infection intensity and fitness. METHODOLOGY/PRINCIPAL FINDINGS Using data from blue tits (Cyanistes caeruleus) in southern Sweden, we investigated the relationship between the intensity of infection of its blood parasite (Haemoproteus majoris) and host survival to the following winter. Presence and intensity of parasite infections were determined by microscopy and confirmed using PCR of a 480 bp section of the cytochrome-b-gene. While a linear model suggested no relationship between parasite intensity and survival (F = 0.01, p = 0.94), a non-linear model showed a significant negative quadratic effect (quadratic parasite intensity: F = 4.65, p = 0.032; linear parasite intensity F = 4.47, p = 0.035). Visualization using the cubic spline technique showed maximum survival at intermediate parasite intensities. CONCLUSIONS/SIGNIFICANCE Our results indicate that failing to recognize the potential for a non-linear relationship between parasite infection intensity and host fitness may lead to the potentially erroneous conclusion that the parasite is harmless to its host. Here we show that high parasite intensities indeed reduced survival, but this effect was masked by reduced survival for birds heavily suppressing their parasite intensities. Reduced survival among hosts with low parasite intensities suggests costs of controlling parasite infections; however, the nature of such costs remains to be elucidated.
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Ishak HD, Dumbacher JP, Anderson NL, Keane JJ, Valkiūnas G, Haig SM, Tell LA, Sehgal RNM. Blood parasites in owls with conservation implications for the Spotted Owl (Strix occidentalis). PLoS One 2008; 3:e2304. [PMID: 18509541 PMCID: PMC2387065 DOI: 10.1371/journal.pone.0002304] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2008] [Accepted: 04/20/2008] [Indexed: 11/19/2022] Open
Abstract
The three subspecies of Spotted Owl (Northern, Strix occidentalis caurina; California, S. o. occidentalis; and Mexican, S. o. lucida) are all threatened by habitat loss and range expansion of the Barred Owl (S. varia). An unaddressed threat is whether Barred Owls could be a source of novel strains of disease such as avian malaria (Plasmodium spp.) or other blood parasites potentially harmful for Spotted Owls. Although Barred Owls commonly harbor Plasmodium infections, these parasites have not been documented in the Spotted Owl. We screened 111 Spotted Owls, 44 Barred Owls, and 387 owls of nine other species for haemosporidian parasites (Leucocytozoon, Plasmodium, and Haemoproteus spp.). California Spotted Owls had the greatest number of simultaneous multi-species infections (44%). Additionally, sequencing results revealed that the Northern and California Spotted Owl subspecies together had the highest number of Leucocytozoon parasite lineages (n = 17) and unique lineages (n = 12). This high level of sequence diversity is significant because only one Leucocytozoon species (L. danilewskyi) has been accepted as valid among all owls, suggesting that L. danilewskyi is a cryptic species. Furthermore, a Plasmodium parasite was documented in a Northern Spotted Owl for the first time. West Coast Barred Owls had a lower prevalence of infection (15%) when compared to sympatric Spotted Owls (S. o. caurina 52%, S. o. occidentalis 79%) and Barred Owls from the historic range (61%). Consequently, Barred Owls on the West Coast may have a competitive advantage over the potentially immune compromised Spotted Owls.
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Affiliation(s)
- Heather D Ishak
- Department of Biology, San Francisco State University, San Francisco, California, United States of America.
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BOURGEON S, VIERA VM, RACLOT T, GROSCOLAS R. Hormones and immunoglobulin levels in king penguins during moulting and breeding fasts. ECOSCIENCE 2007. [DOI: 10.2980/1195-6860(2007)14[519:hailik]2.0.co;2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Bunbury N, Barton E, Jones CG, Greenwood AG, Tyler KM, Bell DJ. Avian blood parasites in an endangered columbid: Leucocytozoon marchouxi in the Mauritian Pink Pigeon Columba mayeri. Parasitology 2007; 134:797-804. [PMID: 17201998 DOI: 10.1017/s0031182006002149] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
There is increasing evidence that pathogens can play a significant role in species decline. This study of a complete free-living species reveals a cost of blood parasitism to an endangered host, the Pink Pigeon Columba mayeri, endemic to Mauritius. We investigated the prevalence and effect of infection of the blood parasite, Leucocytozoon marchouxi, in the free-living Pink Pigeon population. Overall, L. marchouxi infection prevalence detected was 18.3%. Juveniles were more likely to be infected than older birds and there was geographical variation in infection prevalence. Survival of birds infected with L. marchouxi was lower than that of uninfected birds to 90 days post-sampling. This study suggests that while common haematozoa are well tolerated in healthy adults, these parasites may have greater pathogenic potential in susceptible juveniles. The study is unusual given its completeness of species sampling (96%) within a short time-period, the accurate host age data, and its focus on blood parasites in a threatened bird species. Species for which long-term life-history data are available for every individual serve as valuable models for dissecting the contribution of particular pathogens to species decline.
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Affiliation(s)
- N Bunbury
- Centre for Ecology, Evolution and Conservation, University of East Anglia, UK.
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Bensch S, Waldenström J, Jonzén N, Westerdahl H, Hansson B, Sejberg D, Hasselquist D. Temporal dynamics and diversity of avian malaria parasites in a single host species. J Anim Ecol 2007; 76:112-22. [PMID: 17184359 DOI: 10.1111/j.1365-2656.2006.01176.x] [Citation(s) in RCA: 156] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
1. We have used molecular methods to unravel a remarkable diversity of parasite lineages in a long-term population study of great reed warblers Acrocephalus arundinaceus that was not foreseen from traditional microscopic examination of blood smears. This diversity includes eight Haemoproteus and 10 Plasmodium lineages of which most probably represent good biological species. 2. Contrary to expectation, the relative frequency of parasite lineages seemed not to change over the 17-year study period and we found no effects of the parasites on a male secondary sexual ornament (song repertoire size) and two measures of fitness (adult survival and production of recruited offspring). 3. We discuss whether the absence of fitness consequences of the parasites might relate to the fact that we have studied the host at the breeding sites in Europe, whereas the transmission seems to take place at the wintering sites in Africa, where the naïve birds encounter the parasites for the first time and the resulting primary infections likely make them sicker than during the chronic phase of the infection. 4. The prevalence of the three most common lineages appeared to fluctuate in parallel with a periodicity of approximately 3-4 years. Theoretical models based on intrinsic interactions between parasite antigen and host immune genes cannot explain such dynamics, suggesting that knowledge of extrinsic parameters such as vector distribution and alternative hosts are required to understand these patterns.
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Affiliation(s)
- Staffan Bensch
- Department of Animal Ecology, Ecology Building, Lund University, S-223 62 Lund Sweden.
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Gasparini J, Roulin A, Gill VA, Hatch SA, Boulinier T. Kittiwakes strategically reduce investment in replacement clutches. Proc Biol Sci 2006; 273:1551-4. [PMID: 16777751 PMCID: PMC1560326 DOI: 10.1098/rspb.2005.3457] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Many life-history traits are expressed interactively in life, but to a varying extent on different occasions. Changes in trait expression can be accounted for by differences in the quality of the environment ('environmental constraint' hypothesis) or by strategic adjustments, if the relative contribution of the trait to fitness varies with time ('strategic allocation' hypothesis). In birds, egg production is lower in replacement clutches than in first clutches, but it is unknown whether this reduction results from an environmental constraint (e.g. food being less available at the time when the replacement clutch is produced) or from a strategic allocation of resources between the two breeding attempts. To distinguish between these two hypotheses, we performed an experiment with black-legged kittiwakes (Rissa tridactyla). Pairs were either food-supplemented or not before the first clutch was laid onwards and we induced them to produce a replacement clutch by removing eggs once when the first clutch was complete. As predicted by the 'strategic allocation' hypothesis, egg production of food-supplemented and non-food-supplemented birds decreased between first and replacement clutches. This suggests that kittiwakes strategically reduce investment in egg production for their replacement clutches compared to first clutches.
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Affiliation(s)
- Julien Gasparini
- Université de Lausanne, Département d'Ecologie Evolution, 1015 Lausanne, Switzerland.
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Kilgas P, Tilgar V, Mand R. Hematological health state indices predict local survival in a small passerine bird, the great tit (Parus major). Physiol Biochem Zool 2006; 79:565-72. [PMID: 16691522 DOI: 10.1086/502817] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/11/2005] [Indexed: 11/03/2022]
Abstract
In birds, it has been shown that reproductive effort may impair parental condition, while the relation of different condition indices to subsequent survival is still poorly understood. In this study, we measured body mass and various hematological condition indices in breeding great tits in relation to local survival. Number and quality of nestlings and the occurrence of second broods, potentially reflecting parents' breeding effort, were also considered in analyses. The great tits, both male and female, that returned the following year had had a higher albumin/globulin ratio, lower plasma globulin concentration, and a lower heterophile/lymphocyte ratio during breeding in the preceding year, compared to those who did not return. Surviving males (but not females) also had had a higher level of circulating lymphocytes, compared to nonsurvivors. There was no correlation between breeding effort and survival. We conclude that better immunological state and lower stress in great tits during breeding were positively related to their survival probability.
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Affiliation(s)
- Priit Kilgas
- Institute of Zoology and Hydrobiology, University of Tartu, Estonia.
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