| 1. |
- Balbontin, Javier, et al.
(författare)
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Age-related change in breeding performance in early life is associated with an increase in competence in the migratory barn swallow Hirundo rustica
- 2007
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Ingår i: Journal of Animal Ecology. - : Wiley. - 1365-2656 .- 0021-8790. ; 76:5, s. 915-925
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Tidskriftsartikel (refereegranskat)abstract
- 1. We investigated age-related changes in two reproductive traits (laying date and annual fecundity) in barn swallows Hirundo rustica L. using a mixed model approach to di-stinguish among between- and within-individual changes in breeding performance with age. 2. We tested predictions of age-related improvements of competence (i.e. constraint hypothesis) and age-related progressive disappearance of poor-quality breeders (i.e. selection hypothesis) to explain age-related increase in breeding performance in early life. 3. Reproductive success increased in early life, reaching a plateau at middle age (e.g. at 3 years of age) and decreasing at older age (> 4 years). Age-related changes in breeding success were due mainly to an effect of female age. 4. Age of both female and male affected timing of reproduction. Final linear mixed effect models (LME) for laying date included main and quadratic terms for female and male age, suggesting a deterioration in reproductive performance at older age for both males and females. 5. We found evidence supporting the constraints hypothesis that increases in competence within individuals, with ageing being the most probable cause of the observed increase in breeding performance with age in early life. Two mechanisms were implicated: (1) advance in male arrival date with age provided middle-aged males with better access to mates. Yearling males arrived later to the breeding grounds and therefore had limited access to high-quality mates. (2) Breeding pairs maintaining bonds for 2 consecutive years (experienced pairs) had higher fecundity than newly formed inexperienced breeding pairs. 6. There was no support for the selection hypothesis because breeding performance was not correlated with life span. 7. We found a within-individual deterioration in breeding and migratory performance (arrival date) in the oldest age-classes consistent with senescence in these reproductive and migratory traits.
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| 2. |
- Bensch, Staffan, et al.
(författare)
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The use of molecular methods in studies of avian haemosporidians
- 2020
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Ingår i: Avian Malaria and Related Parasites in the Tropics : Ecology, Evolution and Systematics - Ecology, Evolution and Systematics. - Cham : Springer International Publishing. - 9783030516321 - 9783030516338 ; , s. 113-135
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Bokkapitel (refereegranskat)abstract
- During the last two decades, molecular methods to study mitochondrial DNA sequence variation have become an important part in the studies of avian haemosporidians. Up until recently, these methods have primarily been used for identification of the parasites and for tentative phylogenetic reconstructions, allowing researchers not trained in traditional parasitology to compare data across the globe. However, with the introduction of genome and transcriptome sequencing, studies are emerging that go deeper into the genetics and molecular biology of the parasites. In this chapter, we describe and summarize the common methods used for genetic barcoding of the parasites and give an introduction of what to take into account when designing a molecular study of avian haemosporidians. This chapter further discusses why nuclear genetic data are needed in order to answer several important ecological and evolutionary questions and which methods to use in order to overcome the obstacles of obtaining nuclear data of the parasites. Finally, this chapter highlights the challenges and opportunities that come with the use of molecular methods, such as how to study and interpret prevalence, the challenge of aborted developments, and how to obtain data for more robust phylogenies and population structure studies of the parasites.
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| 3. |
- Ferraguti, Martina, et al.
(författare)
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Environmental, geographical and time-related impacts on avian malaria infections in native and introduced populations of house sparrows (Passer domesticus), a globally invasive species
- 2023
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Ingår i: Global Ecology and Biogeography. - : Wiley. - 1466-822X .- 1466-8238. ; 32:5, s. 809-823
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Tidskriftsartikel (refereegranskat)abstract
- Aim: The increasing spread of vector-borne diseases has resulted in severe health concerns for humans, domestic animals and wildlife, with changes in land use and the introduction of invasive species being among the main possible causes for this increase. We explored several ecological drivers potentially affecting the local prevalence and richness of avian malaria parasite lineages in native and introduced house sparrows (Passer domesticus) populations. Location: Global. Time period: 2002–2019. Major taxa studied: Avian Plasmodium parasites in house sparrows. Methods: We analysed data from 2,220 samples from 69 localities across all continents, except Antarctica. The influence of environment (urbanization index and human density), geography (altitude, latitude, hemisphere) and time (bird breeding season and years since introduction) were analysed using generalized additive mixed models (GAMMs) and random forests. Results: Overall, 670 sparrows (30.2%) were infected with 22 Plasmodium lineages. In native populations, parasite prevalence was positively related to urbanization index, with the highest prevalence values in areas with intermediate urbanization levels. Likewise, in introduced populations, prevalence was positively associated with urbanization index; however, higher infection occurred in areas with either extreme high or low levels of urbanization. In introduced populations, the number of parasite lineages increased with altitude and with the years elapsed since the establishment of sparrows in a new locality. Here, after a decline in the number of parasite lineages in the first 30 years, an increase from 40 years onwards was detected. Main conclusions: Urbanization was related to parasite prevalence in both native and introduced bird populations. In invaded areas, altitude and time since bird introduction were related to the number of Plasmodium lineages found to be infecting sparrows.
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| 4. |
- Ferraguti, Martina, et al.
(författare)
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From Africa to Europe : evidence of transmission of a tropical Plasmodium lineage in Spanish populations of house sparrows
- 2019
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Ingår i: Parasites & Vectors. - : Springer Science and Business Media LLC. - 1756-3305. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Avian malaria parasites are a highly diverse group that commonly infect birds and have deleterious effects on their hosts. Some parasite lineages are geographically widespread and infect many host species in many regions. Bird migration, natural dispersal, invasive species and human-mediated introductions into areas where competent insect vectors are present, are probably the main drivers of the current distribution of avian malaria parasites. METHODS: A total of 412 and 2588 wild house sparrows (Passer domesticus) were captured in 2012 and 2013 in two areas of the Iberian Peninsula (central and southern Spain, respectively). Genomic DNA was extracted from blood samples; parasite lineages were sequenced and identified by comparing with GenBank and/or MalAvi databases. RESULTS: Thirteen Plasmodium lineages were identified in house sparrows corresponding to three major clades. Five individuals were infected by the African Plasmodium lineage PAGRI02, which has been proposed to actively circulate only in Africa. CONCLUSIONS: Despite the low prevalence of PAGRI02 in sparrows in Spain, our results suggest that the area of transmission of this parasite is more widespread than previously thought and covers both Africa and Europe. Further studies of the global distribution of Plasmodium lineages infecting wild birds are required to identify the current transmission areas of these parasites. This is vital given the current scenario of global change that is providing new opportunities for avian malaria transmission into areas where parasites were previously absent.
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| 5. |
- Garcia-Longoria, Luz, et al.
(författare)
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Detecting transmission areas of malaria parasites in a migratory bird species.
- 2015
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Ingår i: Parasitology. - 1469-8161. ; 142:9, s. 1215-1220
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Tidskriftsartikel (refereegranskat)abstract
- The identification of the regions where vector-borne diseases are transmitted is essential to study transmission patterns and to recognize future changes in environmental conditions that may potentially influence the transmission areas. SGS1, one of the lineages of Plasmodium relictum, is known to have active transmission in tropical Africa and temperate regions of Europe. Nuclear sequence data from isolates infected with SGS1 (based on merozoite surface protein 1 (MSP1) allelic diversity) have provided new insights on the distribution and transmission areas of these allelic variants. For example, MSP1 alleles transmitted in Africa differ from those transmitted in Europe, suggesting the existence of two populations of SGS1 lineages. However, no study has analysed the distribution of African and European transmitted alleles in Afro-Palearctic migratory birds. With this aim, we used a highly variable molecular marker to investigate whether juvenile house martins become infected in Europe before their first migration to Africa. We explored the MSP1 allelic diversity of P. relictum in adult and juvenile house martins. We found that juveniles were infected with SGS1 during their first weeks of life, confirming active transmission of SGS1 to house martins in Europe. Moreover, we found that all the juveniles and most of adults were infected with one European transmitted MSP1 allele, whereas two adult birds were infected with two African transmitted MSP1 alleles. These findings suggest that house martins are exposed to different strains of P. relictum in their winter and breeding quarters.
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| 6. |
- Garcia-Longoria, Luz, et al.
(författare)
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Diversity and host assemblage of avian haemosporidians in different terrestrial ecoregions of Peru
- 2022
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Ingår i: Current Zoology. - : Oxford University Press (OUP). - 1674-5507 .- 2396-9814. ; 68:1, s. 27-40
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Tidskriftsartikel (refereegranskat)abstract
- Characterizing the diversity and structure of host-parasite communities is crucial to understanding their eco-evolutionary dynamics. Malaria and related haemosporidian parasites are responsible for fitness loss and mortality in bird species worldwide. However, despite exhibiting the greatest ornithological biodiversity, avian haemosporidians from Neotropical regions are quite unexplored. Here, we analyze the genetic diversity of bird haemosporidian parasites (Plasmodium and Haemoproteus) in 1,336 individuals belonging to 206 bird species to explore for differences in diversity of parasite lineages and bird species across 5 well-differentiated Peruvian ecoregions. We detected 70 different haemosporidian lineages infecting 74 bird species. We showed that 25 out of the 70 haplotypes had not been previously recorded. Moreover, we also identified 81 new host-parasite interactions representing new host records for these haemosporidian parasites. Our outcomes revealed that the effective diversity (as well as the richness, abundance, and Shannon-Weaver index) for both birds and parasite lineages was higher in Amazon basin ecoregions. Furthermore, we also showed that ecoregions with greater diversity of bird species also had high parasite richness, hence suggesting that host community is crucial in explaining parasite richness. Generalist parasites were found in ecoregions with lower bird diversity, implying that the abundance and richness of hosts may shape the exploitation strategy followed by haemosporidian parasites. These outcomes reveal that Neotropical region is a major reservoir of unidentified haemosporidian lineages. Further studies analyzing host distribution and specificity of these parasites in the tropics will provide important knowledge about phylogenetic relationships, phylogeography, and patterns of evolution and distribution of haemosporidian parasites.
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| 7. |
- Garcia-Longoria, Luz, et al.
(författare)
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Host-parasite interaction explains variation in the prevalence of avian haemosporidians at the community level
- 2019
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 14:3
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Tidskriftsartikel (refereegranskat)abstract
- Parasites are a selective force that shape host community structure and dynamics, but host communities can also influence parasitism. Understanding the dual nature from host-parasite interactions can be facilitated by quantifying the variation in parasite prevalence among host species and then comparing that variation to other ecological factors that are known to also shape host communities. Avian haemosporidian parasites (e.g. Plasmodium and Haemoproteus) are abundant and widespread representing an excellent model for the study of host-parasite interactions. Several geographic and environmental factors have been suggested to determine prevalence of avian haemosporidians in bird communities. However, it remains unknown whether host and parasite traits, represented by phylogenetic distances among species and degree of specialization in host-parasite relationships, can influence infection status. The aims of this study were to analyze factors affecting infection status in a bird community and to test whether the degree of parasite specialization on their hosts is determined by host traits. Our statistical analyses suggest that infection status is mainly determined by the interaction between host species and parasite lineages where tolerance and/or susceptibility to parasites plays an essential role. Additionally, we found that although some of the parasite lineages infected a low number of bird individuals, the species they infected were distantly related and therefore the parasites themselves should not be considered typical host specialists. Infection status was higher for generalist than for specialist parasites in some, but not all, host species. These results suggest that detected prevalence in a species mainly results from the interaction between host immune defences and parasite exploitation strategies wherein the result of an association between particular parasite lineages and particular host species is idiosyncratic.
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| 8. |
- Garcia-Longoria, Luz, et al.
(författare)
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Reciprocal positive effects on parasitemia between coinfecting haemosporidian parasites in house sparrows
- 2022
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Ingår i: BMC Ecology and Evolution. - : Springer Science and Business Media LLC. - 2730-7182. ; 22:1
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Tidskriftsartikel (refereegranskat)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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| 9. |
- Hellgren, Olof, et al.
(författare)
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Global phylogeography of the avian malaria pathogen Plasmodium relictum based on MSP1 allelic diversity
- 2015
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Ingår i: Ecography. - : Wiley. - 1600-0587 .- 0906-7590. ; 38:8, s. 842-850
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Tidskriftsartikel (refereegranskat)abstract
- Knowing the genetic variation that occurs in pathogen populations and how it is distributed across geographical areas is essential to understand parasite epidemiology, local patterns of virulence, and evolution of host-resistance. In addition, it is important to identify populations of pathogens that are evolutionarily independent and thus free' to adapt to hosts and environments. Here, we investigated genetic variation in the globally distributed, highly invasive avian malaria parasite Plasmodium relictum, which has several distinctive mitochondrial haplotyps (cyt b lineages, SGS1, GRW11 and GRW4). The phylogeography of P. relictum was accessed using the highly variable nuclear gene merozoite surface protein 1 (MSP1), a gene linked to the invasion biology of the parasite. We show that the lineage GRW4 is evolutionarily independent of GRW11 and SGS1 whereas GRW11 and SGS1 share MSP1 alleles and thus suggesting the presence of two distinct species (GRW4 versus SGS1 and GRW11). Further, there were significant differences in the global distribution of MSP1 alleles with differences between GRW4 alleles in the New and the Old World. For SGS1, a lineage formerly believed to have both tropical and temperate transmission, there were clear differences in MSP1 alleles transmitted in tropical Africa compared to the temperate regions of Europe and Asia. Further, we highlight the occurrence of multiple MSP1 alleles in GRW4 isolates from the Hawaiian Islands, where the parasite has contributed to declines and extinctions of endemic forest birds since it was introduced. This study stresses the importance of multiple independent loci for understanding patterns of transmission and evolutionary independence across avian malaria parasites.
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| 10. |
- Hermansen, Jo S., et al.
(författare)
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Hybrid speciation through sorting of parental incompatibilities in Italian sparrows
- 2014
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Ingår i: Molecular Ecology. - : Wiley. - 0962-1083. ; 23, s. 5831-5842
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Tidskriftsartikel (refereegranskat)abstract
- Speciation by hybridization is emerging as a significant contributor to biological diversification. Yet, little is known about the relative contributions of (i) evolutionary novelty and (ii) sorting of pre-existing parental incompatibilities to the build-up of reproductive isolation under this mode of speciation. Few studies have addressed empirically whether hybrid animal taxa are intrinsically isolated from their parents, and no study has so far investigated by which of the two aforementioned routes intrinsic barriers evolve. Here, we show that sorting of pre-existing parental incompatibilities contributes to intrinsic isolation of a hybrid animal taxon. Using a genomic cline framework, we demonstrate that the sex-linked and mitonuclear incompatibilities isolating the homoploid hybrid Italian sparrow at its two geographically separated hybrid–parent boundaries represent a subset of those contributing to reproductive isolation between its parent species, house and Spanish sparrows. Should such a sorting mechanism prove to be pervasive, the circumstances promoting homoploid hybrid speciation may be broader than currently thought, and indeed, there may be many cryptic hybrid taxa separated from their parent species by sorted, inherited incompatibilities.
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