| 1. |
- Perez-Rodriguez, Anton, et al.
(författare)
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Evolution of seasonal transmission patterns in avian blood-borne parasites
- 2015
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Ingår i: International Journal for Parasitology. - : Elsevier BV. - 0020-7519. ; 45:9-10, s. 605-611
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Tidskriftsartikel (refereegranskat)abstract
- In temperate regions, many vector-borne parasites maximise their transmission prospects by adjusting reproduction to seasonal cycles of host susceptibility and vector availability. Nevertheless, in these regions there are areas where environmental conditions are favourable throughout the year, so that parasites could benefit from a year-round transmission strategy. We analysed how different transmission strategies (strict summer transmission, extended summer transmission - including spring and autumn, and year round transmission) have evolved among the different genetic lineages of Haemoproteus parabelopolskyi, an avian blood-borne parasite shared by three sibling species of passerine hosts. Our results indicate that the ancestral state of this clade of parasites had a strict summer transmission with the blackcap (Sylvia atricapilla) as the host. Other transmission strategies and switches to the other host species (Sylvia abyssinica and Sylvia born) evolved recently, several times, independently. This suggests that, although year-round transmission is ecologically successful at present, seasonal transmission may have become more stable over evolutionary time. Switches from strict summer to an extended or year-round transmission strategy could have ecological consequences, if they promote the spread of parasites into more distant regions, transported by the migrating bird hosts. Therefore, a deeper knowledge of how different parasite transmission strategies are structured among birds in temperate areas is essential for understanding how disease emergence risks may develop in the future. (C) 2015 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.
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| 2. |
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| 3. |
- Bensch, Staffan, et al.
(författare)
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Linkage between nuclear and mitochondrial DNA sequences in avian malaria parasites: Multiple cases of cryptic speciation?
- 2004
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Ingår i: Evolution. - : Wiley. - 1558-5646 .- 0014-3820. ; 58:7, s. 1617-1621
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Tidskriftsartikel (refereegranskat)abstract
- Analyses of mitochondrial cytochrome b diversity among avian blood parasites of the genera Haemoproteus and Plasmodium suggest that there might be as many lineages of parasites as there are species of birds. This is in sharp contrast to the approximately 175 parasite species described by traditional methods based on morphology using light microscopy. Until now it has not been clear to what extent parasite mitochondrial DNA lineage diversity reflects intra- or interspecific variation. We have sequenced part of a fast-evolving nuclear gene, dihydrofolate reductase-thymidylate synthase (DHFR-TS), and demonstrate that most of the parasite mitochondrial DNA lineages are associated with unique gene copies at this locus. Although these parasite lineages sometimes coexist in the same host individual, they apparently do not recombine and could therefore be considered as functionally distinct evolutionary entities, with independent evolutionary potential. Studies examining parasite virulence and host immune systems must consider this remarkable diversity of avian malaria parasites.
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| 4. |
- Bensch, Staffan, et al.
(författare)
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MalAvi : A public database of malaria parasites and related haemosporidians in avian hosts based on mitochondrial cytochrome b lineages
- 2009
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Ingår i: Molecular Ecology Resources. - : Wiley. - 1755-098X .- 1755-0998. ; 9:5, s. 1353-1358
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Tidskriftsartikel (refereegranskat)abstract
- Research in avian blood parasites has seen a remarkable increase since the introduction of polymerase chain reaction-based methods for parasite identification. New data are revealing complex multihost-multiparasite systems which are difficult to understand without good knowledge of the host range and geographical distribution of the parasite lineages. However, such information is currently difficult to obtain from the literature, or from general repositories such as GenBank, mainly because (i) different research groups use different parasite lineage names, (ii) GenBank entries frequently refer only to the first host and locality at which each parasite was sampled, and (iii) different researchers use different gene fragments to identify parasite lineages. We propose a unified database of avian blood parasites of the genera Plasmodium, Haemoproteus and Leucocytozoon identified by a partial region of their cytochrome b sequences. The database uses a standardized nomenclature to remove synonymy, and concentrates all available information about each parasite in a public reference site, thereby facilitating access to all researchers. Initial data include a list of host species and localities, as well as genetic markers that can be used for phylogenetical analyses. The database is free to download and will be regularly updated by the authors. Prior to publication of new lineages, we encourage researchers to assign names to match the existing database. We anticipate that the value of the database as a source for determining host range and geographical distribution of the parasites will grow with its size and substantially enhance the understanding of this remarkably diverse group of parasites.
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| 5. |
- Bonneaud, C, et al.
(författare)
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Major histocompatibility alleles associated with local resistance to malaria in a passerine
- 2006
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Ingår i: Evolution. - 1558-5646. ; 60:2, s. 383-389
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Tidskriftsartikel (refereegranskat)abstract
- Malaria parasites are a major cause of human mortality in tropical countries and a potential threat for wildlife, as witnessed by the malaria-induced extinction of naive Hawaiian avifauna. Identifying resistance mechanisms is therefore crucial both for human health and wildlife conservation. Patterns of malaria resistance are known to be highly polygenic in both humans and mice, with marked contributions attributed to major histocompatibility (Mhc) genes. Here we show that specific Mhc variants are linked to both increased resistance and susceptibility to malaria infection in a wild passerine species, the house sparrow (Passer domesticus). In addition, links between host immunogenctics and resistance to malaria involved population-specific alleles, suggesting local adaptation in this host-parasite interaction. This is the first evidence for a population-specific genetic control of resistance to malaria in a wild species.
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| 6. |
- de la Hera, Ivan, et al.
(författare)
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How much variation in the molt duration of passerines can be explained by the growth rate of tail feathers?
- 2011
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Ingår i: The Auk. - : Oxford University Press (OUP). - 0004-8038 .- 1938-4254. ; 128:2, s. 321-329
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Tidskriftsartikel (refereegranskat)abstract
- In birds, molt duration is an important trait that can affect plumage functionality and, consequently, the fitness of individuals. However, knowledge about the factors that affect variation in molt speed is sparse, mostly because of the methodological difficulties of studying avian molt. We used a ptilochronology-based approach to estimate the rate at which tail feathers were produced during molt to shed light on the relationship between molt duration and feather growth rate. For that purpose, we used three data sets. First, we tested whether the average molt durations of 22 passerine species were correlated with the mean growth rates of their feathers, using both conventional and phylogenetically corrected statistical procedures. Second, we explored this same association among captive Great Tits (Pants major). And third, we took advantage of the biannual complete molt of Willow Warblers (Phylloscopus trochilus) to examine whether the feathers synthesized during their short summer molt grew faster than those produced during their long winter molt. Feather growth rates were negatively correlated with molt duration in all analyses, revealing that molt duration can be estimated from the growth rate of a single feather. However, predictive power was limited by the fact that molt duration is modulated mainly by molt intensity, which seems to be correlated with ecological constraints in our interspecific approach. We also discuss the implications of our results for the evolution of molt duration, and the potential application of ptilochronology in its study. Received 2 August 2010, accepted 21 December 2010.
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| 7. |
- de la Hera, Ivan, et al.
(författare)
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Structural and Mechanical Differences between Original and Replaced Feathers in Blackcaps Sylvia Atricapilla
- 2010
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Ingår i: Ardeola. - 0570-7358. ; 57:2, s. 431-436
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Tidskriftsartikel (refereegranskat)abstract
- Many bird species are able to replace accidentally lost feathers out of the normal moulting periods, but whether such replaced feathers are able to restore the original mechanical properties of the plumage has not been evaluated before. In this study we analysed the structure and mechanical behaviour of the original and replaced feathers of 12 blackcaps Sylvia atricapilla. Replaced feathers showed wider rachis and greater density of barbs, but were lighter, shorter and less stiff than original feathers. These results suggest that replaced feathers are not able to fully restore the original functionality of feathers.
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| 8. |
- de la Hera, Ivan, et al.
(författare)
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Variation in the mechanical properties of flight feathers of the blackcap Sylvia atricapilla in relation to migration
- 2010
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Ingår i: Journal of Avian Biology. - 0908-8857. ; 41:3, s. 342-347
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Tidskriftsartikel (refereegranskat)abstract
- Migration causes temporal and energetic constraints during plumage development, which can compromise feather structure and function. In turn, given the importance of a good quality of flight feathers in migratory movements, selection may have favoured the synthesis of feathers with better mechanical properties than expected from a feather production constrained by migration necessities. However, no study has assessed whether migratory behaviour affects the relationship between the mechanical properties of feathers and their structural characteristics. We analysed bending stiffness (a feather mechanical property which is relevant to birds' flight), rachis width and mass (two main determinants of variation in bending stiffness) of wing and tail feathers in migratory and sedentary blackcaps Sylvia atricapilla. Migratory blackcaps produced feathers with a narrower rachis in both wing and tail, but their feathers were not significantly lighter; in addition, bending stiffness was higher in migratory blackcaps than in sedentary blackcaps. Such unexpected result for bending stiffness remained when we statistically controlled for individual variation in rachis width and feather mass, which suggests the existence of specific mechanisms that help migratory blackcaps to improve the mechanical behaviour of their feathers under migration constraints.
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| 9. |
- Diaz, JA, et al.
(författare)
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Reproductive investment of a lacertid lizard in fragmented habitat
- 2005
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Ingår i: Conservation Biology. - : Wiley. - 0888-8892 .- 1523-1739. ; 19:5, s. 1578-1585
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Tidskriftsartikel (refereegranskat)abstract
- We studied the effect of habitat fragmentation on female reproductive investment in a widespread lacertid lizard (Psammodromus algirus) in a mixed-forest archipelago of deciduous and evergreen oak woods in northern Spain. We captured gravid females in fragments (<= 10 ha) and forests (>= 200 ha) and brought them to the laboratory, where they laid their eggs. We incubated the eggs and released the first cohort of juveniles into the wild to monitor their survival. Females from fragments produced a smaller clutch mass and laid fewer eggs (relative to mean egg mass) than females of similar body size from forests. Lizards did not trade larger clutches for larger offspring, however, because females from fragments did not lay larger eggs (relative to their number) than females from forests. Among the first cohort of juveniles, larger egg mass and body size increased the probability of recapture the next year Thus, fragmentation decreased the relative fecundity of lizards without increasing the quality of their offspring. Reduced energy availability, increased predation risk, and demographic stochasticity could decrease the fitness of lizards in fragmented habitats, which could contribute to the regional scarcity of this species in agricultural areas sprinkled with small patches of otherwise suitable forest. Our results show that predictable reduction of reproductive output with decreasing size of habitat patches can be added to the already known processes that cause inverse density dependence at low population numbers.
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| 10. |
- Ewen, John G., et al.
(författare)
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Establishment of exotic parasites: the origins and characteristics of an avian malaria community in an isolated island avifauna
- 2012
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Ingår i: Ecology Letters. - : Wiley. - 1461-023X. ; 15:10, s. 1112-1119
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Tidskriftsartikel (refereegranskat)abstract
- Knowledge of the processes favouring the establishment of exotic parasites is poor. Herein, we test the characteristics of successful exotic parasites that have co-established in the remote island archipelago of New Zealand, due to the introduction of numerous avian host species. Our results show that avian malaria parasites (AM; parasites of the genus Plasmodium) that successfully invaded are more globally generalist (both geographically widespread and with a broad taxonomic range of hosts) than AM parasites not co-introduced to New Zealand. Furthermore, the successful AM parasites are presently more prevalent in their native range than AM parasites found in the same native range but not co-introduced to New Zealand. This has resulted in an increased number and greater taxonomic diversity of AM parasites now in New Zealand.
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| 11. |
- 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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| 12. |
- Fuller, Trevon, et al.
(författare)
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The Ecology of Emerging Infectious Diseases in Migratory Birds: An Assessment of the Role of Climate Change and Priorities for Future Research
- 2012
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Ingår i: EcoHealth. - : Springer Science and Business Media LLC. - 1612-9202 .- 1612-9210. ; 9:1, s. 80-88
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Forskningsöversikt (refereegranskat)abstract
- Pathogens that are maintained by wild birds occasionally jump to human hosts, causing considerable loss of life and disruption to global commerce. Preliminary evidence suggests that climate change and human movements and commerce may have played a role in recent range expansions of avian pathogens. Since the magnitude of climate change in the coming decades is predicted to exceed climatic changes in the recent past, there is an urgent need to determine the extent to which climate change may drive the spread of disease by avian migrants. In this review, we recommend actions intended to mitigate the impact of emergent pathogens of migratory birds on biodiversity and public health. Increased surveillance that builds upon existing bird banding networks is required to conclusively establish a link between climate and avian pathogens and to prevent pathogens with migratory bird reservoirs from spilling over to humans.
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| 13. |
- Hellgren, Olof, et al.
(författare)
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A jack-of-all-trades and still a master of some: prevalence and host range in avian malaria and related blood parasites
- 2009
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Ingår i: Ecology. - : Wiley. - 0012-9658. ; 90:10, s. 2840-2849
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Tidskriftsartikel (refereegranskat)abstract
- A parasite's ability to be a specialist vs. a generalist may have consequences for its prevalence within one or more if its host species. In this study we investigated the relationship between host specialization and prevalence in the highly species diverse avian blood parasites of the genera Plasmodium and Haemoproteus. Contrary to trade-off hypotheses that may explain host specialization, within both genera the parasites with the ability to complete their life cycles and be transmitted across a wide host range ( broad compatibility) were also the most common parasites within their compatible host species. These patterns remained unchanged when the host species with the highest prevalence were excluded, which reduces the possibility that the observed pattern was caused by parasites reaching high prevalence in a single main host, and being "spilled over" to other host species. We hypothesize that a positive relationship between parasite host range and prevalence might be explained by an overall higher encounter rate for the parasites with broad host range, which compensates for possibly reduced performance of parasites in each host species. Overall, these results show that parasites with the ability to successfully infect a wide variety of host species of broad ancestry also can have the ability to be the most prevalent in single host species.
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| 14. |
- Hellgren, Olof, et al.
(författare)
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Detecting shifts of transmission areas in avian blood parasites - a phylogenetic approach
- 2007
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Ingår i: Molecular Ecology. - 0962-1083. ; 16:6, s. 1281-1290
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the degree of geographical shifts of transmission areas of vector-borne avian blood parasites (Plasmodium, Haemoproteus and Leucocytozoon) over ecological and evolutionary timescales. Of 259 different parasite lineages obtained from 5886 screened birds sampled in Europe and Africa, only two lineages were confirmed to have current transmission in resident bird species in both geographical areas. We used a phylogenetic approach to show that parasites belonging to the genera Haemoproteus and Leucocytozoon rarely change transmission area and that these parasites are restricted to one resident bird fauna over a long evolutionary time span and are not freely spread between the continents with the help of migratory birds. Lineages of the genus Plasmodium seem more freely spread between the continents. We suggest that such a reduced transmission barrier of Plasmodium parasites is caused by their higher tendency to infect migratory bird species, which might facilitate shifting of transmission area. Although vector-borne parasites of these genera apparently can shift between a tropical and a temperate transmission area and these areas are linked with an immense amount of annual bird migration, our data suggest that novel introductions of these parasites into resident bird faunas are rather rare evolutionary events.
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| 15. |
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| 16. |
- Krizanauskiene, Asta, et al.
(författare)
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Molecular phylogenetic and morphological analysis of haemosporidian parasites (Haemosporida) in a naturally infected European songbird, the blackcap Sylvia atricapilla, with description of Haemoproteus pallidulus sp. nov
- 2010
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Ingår i: Parasitology. - 1469-8161. ; 137:2, s. 217-227
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Tidskriftsartikel (refereegranskat)abstract
- The blackcap (Sylvia atricapilla) is a common Palearctic migratory warbler, and haemosporidian parasites are common in this species. However, genetic and phenotypic diversity of haemosporidians in warblers has been insufficiently investigated and poorly linked. We addressed this issue by combining molecular and microscopy data for detection of pigment-forming haemosporidians of the genera Haemoproteus and Plasmodium. Blood samples from 498 blackcaps were collected at 7 different sites in Europe and investigated for these parasites by polymerase chain reaction (PCR)-based techniques and microscopic examination. In all, 56% of the birds were infected by at least 1 out of 25 distinct mitochondrial cytochrome b (cyt b) gene lineages of these haemosporidians. It is concluded that the blackcap is infected not only with blackcap specific haemosporidians, but also with Haemoproteus majoris, which is a host generalist and common in birds belonging to the Paridae. Haemoproteus pallidulus sp. nov. is described based on morphology of its blood stages and segments of the cyt b and dihydrofolate reductase/thymidylate synthase (DHFR-TS) genes. This study provides evidence that genetic diversity of haemosporidian parasites might be positively correlated with migratory strategies of their avian hosts; it also contributes to the value of both microscopy and molecular diagnostics of avian blood parasites.
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| 17. |
- Marzal, Alfonso, et al.
(författare)
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Diversity, Loss, and Gain of Malaria Parasites in a Globally Invasive Bird.
- 2011
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 6:7
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Tidskriftsartikel (refereegranskat)abstract
- Invasive species can displace natives, and thus identifying the traits that make aliens successful is crucial for predicting and preventing biodiversity loss. Pathogens may play an important role in the invasive process, facilitating colonization of their hosts in new continents and islands. According to the Novel Weapon Hypothesis, colonizers may out-compete local native species by bringing with them novel pathogens to which native species are not adapted. In contrast, the Enemy Release Hypothesis suggests that flourishing colonizers are successful because they have left their pathogens behind. To assess the role of avian malaria and related haemosporidian parasites in the global spread of a common invasive bird, we examined the prevalence and genetic diversity of haemosporidian parasites (order Haemosporida, genera Plasmodium and Haemoproteus) infecting house sparrows (Passer domesticus). We sampled house sparrows (N = 1820) from 58 locations on 6 continents. All the samples were tested using PCR-based methods; blood films from the PCR-positive birds were examined microscopically to identify parasite species. The results show that haemosporidian parasites in the house sparrows' native range are replaced by species from local host-generalist parasite fauna in the alien environments of North and South America. Furthermore, sparrows in colonized regions displayed a lower diversity and prevalence of parasite infections. Because the house sparrow lost its native parasites when colonizing the American continents, the release from these natural enemies may have facilitated its invasion in the last two centuries. Our findings therefore reject the Novel Weapon Hypothesis and are concordant with the Enemy Release Hypothesis.
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| 18. |
- Perez-Tris, Javier, et al.
(författare)
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Are Iberian Chiffchaffs Phylloscopus (collybita) brehmii long-distance migrants? An analysis of flight-related morphology
- 2003
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Ingår i: Bird Study. - 0006-3657. ; 50:2, s. 146-152
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Tidskriftsartikel (refereegranskat)abstract
- Capsule Iberian Chiffchaffs Phylloscopus (collybita) brehmii are genetically, morphologically and bioacoustically different from European Chiffchaffs (P [c.] collybita). Aim To examine the difference in migratory pattern between brehmii and collybita. Methods We inferred variation in distance of migration between brehmii and collybita by analysing differences in flight-related morphology (wing-length, wing shape and tail-length) between individuals breeding or wintering in the Iberian Peninsula. Results Controlling for body size and allometry of feather dimensions, birds captured in spring had more pointed wings (more concave wing shapes and pointed wing tips) and a shorter tail than birds caught in winter, although no spring-to-winter difference was found for wing-length. Conclusion Iberian breeders appear better suited to long-distance migration (their traits are likely to give a higher speed and a lower energy consumption during long non-stop flights) than wintering individuals, which strongly supports the hypothesis that brehmii move south of the Sahara in autumn and are substituted by central European collybita populations in winter. This different migration pattern of brehmii and collybita has important implications for the maintenance of differentiation in their contact zone, because selection against hybrids with maladaptive, intermediate migratory behaviours might contribute to reproductive isolation.
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| 19. |
- Perez-Tris, Javier, et al.
(författare)
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Diagnosing genetically diverse avian malarial infections using mixed-sequence analysis and TA-cloning
- 2005
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Ingår i: Parasitology. - 1469-8161. ; 131:1, s. 15-23
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Tidskriftsartikel (refereegranskat)abstract
- Birds harbouring several malarial parasites are common in the wild, and resolving such multiple infections is important for our understanding of host-parasite relationships. We propose a simple and reasonably accurate method for detecting and resolving multiple infections, based on the analysis of parasite cytochrome b DNA sequences: genetically mixed infections are first identified by double nucleotide peaks on sequence electropherograms, and later retrieved by TA-cloning. We applied this method to wild birds, and to experimentally created mixes with varying proportion of two parasites (Plasmodium spp. and Haemoproteus spp.). In general, the method was very efficient in detecting and resolving multiple infections, but some problems were encountered. Several multiple infections were erroneously scored as simple, either because one of the parasite lineages was a better target for the primers used, or because it was much more abundant in the mix. On the other hand, single nucleotide substitutions and template switching during PCR produced artificial sequences in some clones. We discuss the utility of the method, and propose a framework for its use when screening for genetically diverse avian malarial parasites.
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| 20. |
- Perez-Tris, Javier, et al.
(författare)
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Dispersal increases local transmission of avian malarial parasites
- 2005
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Ingår i: Ecology Letters. - : Wiley. - 1461-023X .- 1461-0248. ; 8:8, s. 838-845
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Tidskriftsartikel (refereegranskat)abstract
- The relationships between dispersal and local transmission rate of parasites are essential to understanding host-parasite coevolution and the emergence and spread of novel disease threats. Here we show that year-round transmission, as opposed to summer transmission, has repeatedly evolved in malarial parasites (genera Plasmodium and Haemoproteus) of a migratory bird. Year-round transmission allows parasites to spread in sympatric host's wintering areas, and hence to colonize distantly located host's breeding areas connected by host-migration movements. Widespread parasites had higher local prevalence, revealing increased transmission, than geographically restricted parasites. Our results show a positive relationship between dispersal and local transmission of malarial parasites that is apparently mediated by frequent evolutionary changes in parasite transmission dynamics, which has important implications for the ecology and evolution of infectious diseases.
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| 21. |
- Perez-Tris, Javier, et al.
(författare)
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Historical diversification of migration patterns in a passerine bird
- 2004
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Ingår i: Evolution. - 1558-5646. ; 58:8, s. 1819-1832
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Tidskriftsartikel (refereegranskat)abstract
- Migratory strategies of birds require complex orientation mechanisms, morphological adaptations, and life-history adjustments. From an evolutionary perspective, it is important to know how fast this complex combination of traits can evolve. We analyzed mitochondrial control-region DNA sequences in 241 blackcaps (Sylvia atricapilla) from 12 populations with different migratory behaviors. The sample included sedentary populations in Europe and Atlantic archipelagos and migratory populations with different distances of migration, from regional to intercontinental migrations, and different heading directions (due to a migratory divide in central Europe). There was no genetic structure between migratory and sedentary populations, or among populations from different biogeographic areas (Atlantic islands, the Iberian Peninsula, or the continent), however we found evidence of a genetic structure when comparing populations located on either side of the migratory divide. These findings support an independent evolution of highly divergent migratory strategies in blackcaps, occurring after a postglacial colonization of the continent along western and eastern routes. Accordingly, mismatch-distribution analyses suggested an expansion of blackcaps from a very small population size, and time estimates dated such an expansion during the last postglacial period. However, the populations in Gibraltar, located in a putative Mediterranean refuge, appeared to be independent of these processes, showing evidence of restricted gene flow with other populations and demonstrating insignificant historical changes in effective population size. Our results show that the interruption of gene flow between migratory and sedentary populations is not necessary for the maintenance of such a polymorphism, and that even the most divergent migratory strategies of a bird species are susceptible to evolution in response to historical environmental changes.
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| 22. |
- Perez-Tris, Javier, et al.
(författare)
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Loss of body mass under predation risk: cost of antipredatory behaviour or adaptive fit-for-escape?
- 2004
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Ingår i: Animal Behaviour. - : Elsevier BV. - 1095-8282 .- 0003-3472. ; 67:3, s. 511-521
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Tidskriftsartikel (refereegranskat)abstract
- Predation risk may compromise the ability of animals to acquire and maintain body reserves by hindering 14 foraging efficiency and increasing physiological stress. Locomotor performance may depend on body mass, so losing mass under predation risk could be an adaptive response of prey to improve escape ability. We studied individual variation in antipredatory behaviour, feeding rate, body mass and escape performance in the lacertid lizard Psammodromus algirus. Individuals were experimentally exposed to different levels of food availability (limited or abundant) and predation risk, represented by reduced refuge availability and simulated predator attacks. Predation risk induced lizards to reduce conspicuousness behaviourally and to avoid feeding in the presence of predators. If food was abundant, alarmed lizards reduced feeding rate, losing mass. Lizards supplied with limited food fed at near-maximum rates independently of predation risk but lost more mass when alarmed; thus, mass losses experienced under predation risk were higher than those expected from feeding interruption alone. Although body mass of lizards varied between treatments, no component of escape performance measured during predator attacks (endurance, speed, escape strategy) was affected by treatments or by variations in body mass. Thus, the body mass changes were consistent with a trade-off between gaining resources and avoiding predators, mediated by hampered foraging efficiency and physiological stress. However, improved escape efficiency is not required to explain mass reduction upon predator encounters beyond that expected from feeding interruption or predation-related stress. Therefore, the idea that animals may regulate body reserves in relation to performance demands should be reconsidered.
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| 23. |
- Perez-Tris, Javier, et al.
(författare)
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Spanish research on avian migration: historical trajectory and future perspectives.
- 2004
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Ingår i: Ardeola. - 0570-7358. ; 51:1, s. 71-89
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Forskningsöversikt (refereegranskat)abstract
- Aim: To value the importance of research on avian migration for the development and current status of Spanish ornithology. Results and Conclusions: Avian migration has always been an outstanding field in ornithology. This assertion is particularly true in Spain, as we illustrate here by discussing the contribution of migration research to both the scientific and historical development of Spanish ornithology. After all, the Iberian Peninsula is one of the best scenarios for the study of migration in Europe (Fig. 1), as it forms natural bridges for birds migrating between Europe and Africa and between the Atlantic Ocean and the Mediterranean Sea. As well, it is one of the main wintering grounds for European birds in the Mediterranean area. Migration ecology experienced a relatively early development in Spain, compared to other fields in ornithology. Short after the foundation of the Spanish Ornithological Society (SEO) in 1954, migration surveys often triggered pioneering attempts to build up long-term research programs (Table 1). Thus, massive ringing campaigns were among the very first scientific activities organised by SEO, and became formally regularised with the creation of the Bird Migration Centre (CMA) in 1957, one of the first successful attempts to institutionalize ornithological research in Spain. Later on, these activities acquired international relevance with the publication of their results in international meetings, and the participation of the CMA in the foundation of EURING. These facts, together with the creation of the Spanish Group of Raptor Migration (GEMRA) for monitoring the passage of soaring birds across the Strait of Gibraltar, were fundamental pieces in the training of a whole generation of Spanish ornithologists. Perhaps migration gained a prominent position relative to other fields in Spain owing to the personal interests of Francisco Bernis, who was responsible, directly or indirectly, of most of the achievements of a newly born Spanish ornithology (from the 1940's to the late 1970's). Leading the foundation of SEO, he published a profuse collection of seminal reports, monographs and handbooks, which pushed forward several fields of ornithology in Spain, but paid special attention to migration. Such interests could be motivated by a late advent of Spanish ornithological research in the international framework: the advantages of the Iberian Peninsula for the study of migration, and the still poor knowledge of the ecological processes occurring south of the scientifically leading countries (central and northern Europe), offered a good opportunity for Bernis' school to make a contribution of general relevance to the scientific community. Thus, the analysis of ringing recoveries in Spain of birds ringed in Europe, the ecological and evolutionary interpretation of wintering in the Mediterranean (Table 1), or the study of visible migration in Gibraltar (Fig. 2) were all major contributions of F. Bernis to the growth and international diffusion of Spanish ornithology. This contribution of migration studies to the maturation of Spanish ornithology is also reflected by nearly as many publications on migration in Ardeola, the Spanish ornithological journal, as there were derived from faunistic research (which traditionally dominated the contents of the journal; Fig. 3). Today, Spanish ornithology has reached a high average standard, being recognised as internationally influential. As a consequence, the research published in Ardeola seeks to broaden its potential readership (using more frequently the English language) and has become increasingly professionalized (Fig. 4). This healthiness of Spanish ornithology in general is also perceived in migration research (Fig. 4). Spanish researchers and amateurs (particularly ringers) are keen to enrol in international co-operative projects, being institutionally supported by the Spanish ringing scheme (Migratory Species Office, Ministry of Environment). As an immediate benefit, this should help us to put our knowledge on migration through and to the Iberian Peninsula in a broader ecological and geographic context. Besides, Spanish researchers are taking advantage of excellent chances to study the ecological and evolutionary implications of migration and wintering in the Mediterranean. Future research should contribute to fulfil the social demand for studies that may help us to foresee the consequences of processes such as climate change or habitat destruction, a research front that both Spanish authorities and scientists have a decisive obligation to push forward.
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| 24. |
- Perez-Tris, Javier, et al.
(författare)
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What are malaria parasites?
- 2005
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Ingår i: Trends in Parasitology. - : Elsevier BV. ; 21:5, s. 209-211
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Tidskriftsartikel (refereegranskat)
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| 25. |
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| 26. |
- Perez-Tris, Javier, et al.
(författare)
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Within-host speciation of malaria parasites
- 2007
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 2:2
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Tidskriftsartikel (refereegranskat)abstract
- Background Sympatric speciation—the divergence of populations into new species in absence of geographic barriers to hybridization—is the most debated mode of diversification of life forms. Parasitic organisms are prominent models for sympatric speciation, because they may colonise new hosts within the same geographic area and diverge through host specialization. However, it has been argued that this mode of parasite divergence is not strict sympatric speciation, because host shifts likely cause the sudden effective isolation of parasites, particularly if these are transmitted by vectors and therefore cannot select their hosts. Strict sympatric speciation would involve parasite lineages diverging within a single host species, without any population subdivision. Methodology/Principal Findings Here we report a case of extraordinary divergence of sympatric, ecologically distinct, and reproductively isolated malaria parasites within a single avian host species, which apparently occurred without historical or extant subdivision of parasite or host populations. Conclusions/Significance This discovery of within-host speciation changes our current view on the diversification potential of malaria parasites, because neither geographic isolation of host populations nor colonization of new host species are any longer necessary conditions to the formation of new parasite species.
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| 27. |
- Piersma, T, et al.
(författare)
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Is there a "migratory syndrome" common to all migrant birds?
- 2005
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Ingår i: Annals of the New York Academy of Sciences. - : Wiley. - 0077-8923. ; 1046, s. 282-293
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Tidskriftsartikel (refereegranskat)abstract
- Bird migration has been assumed, mostly implicitly, to represent a distinct class of animal behavior, with deep and strong homologies in the various phenotypic expressions of migratory behavior between different taxa. Here the evidence for the existence of what could be called a "migratory syndrome," a tightly integrated, old group of adaptive traits that enables birds to commit themselves to highly organized seasonal migrations, is assessed. A list of problems faced by migratory birds is listed first and the traits that migratory birds have evolved to deal with these problems are discussed. The usefulness of comparative approaches to investigate which traits are unique to migrants is then discussed. A provisional conclusion that, perhaps apart from a capacity for night-time compass orientation, there is little evidence for deeply rooted co-adapted trait complexes that could make up such a migratory syndrome, is suggested. Detailed analyses of the genetic and physiological architecture of potential adaptations to migration, combined with a comparative approach to further identify the phylogenetic levels at which different adaptive traits for migration have evolved, are recommended.
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| 28. |
- Reullier, J, et al.
(författare)
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Diversity, distribution and exchange of blood parasites meeting at an avian moving contact zone
- 2006
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Ingår i: Molecular Ecology. - 0962-1083. ; 15:3, s. 753-763
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Tidskriftsartikel (refereegranskat)abstract
- Research on contact zones has paid relatively little attention to host-parasite interactions, although these situations have important but different implications depending on whether one considers the host or the parasite's perspective. We investigated both the role of a host contact zone in parasite expansion and whether parasites could influence contact zone dynamics. We studied the diversity and the patterns of parasite exchange (genera Haemoproteus and Plasmodium) infecting two parapatric sibling passerines meeting at a moving contact zone in western Europe. We amplified and sequenced a fragment of the parasite cytochrome b gene. The expanding host harboured more diverse parasites, which might indicate a superior ability to face a diverse parasite fauna than the receding host. Prevalence was very high in both hosts, due to the frequent occurrence of two sister Haemoproteus lineages. Despite the recent movement of the contact zone, these two parasites fitted almost perfectly to the geographic range of their main host species. Yet, we found several cases of cross-species infection in sympatric areas and evidences of asymmetrical spreading of parasites from the expanding host towards the receding host. Altogether, our results suggest that the host contact zone mainly acts as a barrier to parasite expansion even if recurrent host shifts are observed. Besides, they also support the idea that parasite-mediated competition might contribute to the displacement of hosts' contact zones, thereby emphasizing the role of parasitism on the population dynamics of sympatric species.
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| 29. |
- Ruiz-Martinez, Jorge, et al.
(författare)
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Prevalence and Genetic Diversity of Avipoxvirus in House Sparrows in Spain
- 2016
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 11:12
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Tidskriftsartikel (refereegranskat)abstract
- Avipoxvirus (APV) is a fairly common virus affecting birds that causes morbidity and mortality in wild and captive birds. We studied the prevalence of pox-like lesions and genetic diversity of APV in house sparrows (Passer domesticus) in natural, agricultural and urban areas in southern Spain in 2013 and 2014 and in central Spain for 8 months (2012-2013). Overall, 3.2% of 2,341 house sparrows visually examined in southern Spain had cutaneous lesions consistent with avian pox. A similar prevalence (3%) was found in 338 birds from central Spain. Prevalence was higher in hatch-year birds than in adults. We did not detect any clear spatial or temporal patterns of APV distribution. Molecular analyses of poxvirus-like lesions revealed that 63% of the samples were positive. Molecular and phylogenetic analyses of 29 DNA sequences from the fpv167 gene, detected two strains belonging to the canarypox clade (subclades B1 and B2) previously found in Spain. One of them appears predominant in Iberia and North Africa and shares 70% similarity to fowlpox and canarypox virus. This APV strain has been identified in a limited number of species in the Iberian Peninsula, Morocco and Hungary. The second one has a global distribution and has been found in numerous wild bird species around the world. To our knowledge, this represents the largest study of avian poxvirus disease in the broadly distributed house sparrow and strongly supports the findings that Avipox prevalence in this species in South and central Spain is moderate and the genetic diversity low.
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| 30. |
- Salmón, Pablo, et al.
(författare)
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Urbanisation impacts plumage colouration in a songbird across Europe : Evidence from a correlational, experimental and meta-analytical approach
- 2023
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Ingår i: Journal of Animal Ecology. - 0021-8790. ; 92:10, s. 1924-1936
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Tidskriftsartikel (refereegranskat)abstract
- Urbanisation is accelerating across the globe, transforming landscapes, presenting organisms with novel challenges, shaping phenotypes and impacting fitness. Urban individuals are claimed to have duller carotenoid-based colouration, compared to their non-urban counterparts, the so-called ‘urban dullness’ phenomenon. However, at the intraspecific level, this generalisation is surprisingly inconsistent and often based on comparisons of single urban/non-urban populations or studies from a limited geographical area. Here, we combine correlational, experimental and meta-analytical data on a common songbird, the great tit Parus major, to investigate carotenoid-based plumage colouration in urban and forest populations across Europe. We find that, as predicted, urban individuals are paler than forest individuals, although there are large population-specific differences in the magnitude of the urban-forest contrast in colouration. Using one focal region (Malmö, Sweden), we reveal population-specific processes behind plumage colouration differences, which are unlikely to be the result of genetic or early-life conditions, but instead a consequence of environmental factors acting after fledging. Finally, our meta-analysis indicates that the urban dullness phenomenon is well established in the literature, for great tits, with consistent changes in carotenoid-based plumage traits, particularly carotenoid chroma, in response to anthropogenic disturbances. Overall, our results provide evidence for uniformity in the ‘urban dullness’ phenomenon but also highlight that the magnitude of the effect on colouration depends on local urban characteristics. Future long-term replicated studies, covering a wider range of species and feeding guilds, will be essential to further our understanding of the eco-evolutionary implications of this phenomenon.
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| 31. |
- Telleria, J L, et al.
(författare)
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Conservation of seed-dispersing migrant birds in Mediterranean habitats: Shedding light on patterns to preserve processes
- 2005
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Ingår i: Biological Conservation. - : Elsevier BV. - 1873-2917 .- 0006-3207. ; 124:4, s. 493-502
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Tidskriftsartikel (refereegranskat)abstract
- Migratory frugivorous birds disperse the seeds of many plant species, forming mutualistic associations that render frugivores a priority for conservation in many habitats worldwide. We analysed the distribution of seed-dispersing frugivorous passerines in southern Spain, which is an important area for the conservation of European birds during winter. Frugivorous birds showed similar regional abundance and richness during four winters, although fruit availability changed among years. However, the spatial distribution of frugivorous birds in the area changed among years. These changes were principally determined by annual variation in the distribution of fruits in the area, revealing a clear ability of birds to track the distribution of fruits. The unpredictable distribution of fruits each year suggests that regional fruit crops, rather than selected habitat patches, need to be protected for the long-term conservation of frugivorous bird populations in wintering grounds. Remarkably, the distribution of frugivores was independent of forest development or general cover of shrubs, which helps to reconcile the protection of fruiting shrubs with forest cleaning, an usual management to prevent devastating summer fires that is destroying fleshy-fruited plant communities in many areas of southern Spain. Thus, leaving a part of the fruiting shrubs untouched when cleaning forest undergrowth will allow the settlement of frugivorous birds. Interestingly, both abundance and richness of frugivores decreased with elevation, probably as a consequence of impaired climatic conditions at high altitude, revealing the importance of lowland shrublands as wintering grounds for frugivorous birds. These habitats deserve special conservation efforts, as they are seriously threatened by the ongoing encroachment of agricultural and urban areas along the Mediterranean coasts.
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| 32. |
- Telleria, J L, et al.
(författare)
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Habitat effects on resource tracking ability: do wintering Blackcaps Sylvia atricapilla track fruit availability?
- 2007
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Ingår i: Ibis. - 0019-1019. ; 149:1, s. 18-25
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Tidskriftsartikel (refereegranskat)abstract
- If resource availability shapes population distribution, changes in resource abundance should cause parallel changes in population numbers. However, tracking ability may be disrupted by different environmental and behavioural factors that act at different spatial and temporal scales. Here we analyse the ability of wintering Blackcap Sylvia atricapilla populations to track spatio-temporal variation in fruit availability in southern Spain in two habitats (forests and shrublands) with different population structure. Former studies had shown that forests are equally used by both adult migrant and local Blackcaps, whereas shrublands are nearly monopolized by juvenile migrants. These differences might affect resource tracking: it should be disrupted in forests, as local birds remain over winter in their breeding territories, but not in shrublands where similarly competitive juvenile migrants can freely track the spatial distribution of fruits. We analysed the fruit-tracking ability of Blackcap populations among sites and years in both habitat types using a habitat-matching model, which predicts spatio-temporal changes in population abundance proportional to changes in resource availability. We counted Blackcaps and fruiting shrubs (dominated by Lentiscs Pistacia lentiscus and Wild Olives Olea europaea sylvestris) during four winters in forest and shrubland patches. The abundance of fruits was always higher in shrublands than in forests. In shrublands, Blackcaps seemed to move freely across fruit-rich habitat patches, tracking changes in fruiting-shrub abundance among sites and years. However, such tracking was not observed in forests. This supports the view that fruit-tracking ability may be constrained by local factors, such as the social structure of populations occurring in different habitat types, which introduces spatio-temporal variation in the way fruit availability shapes the abundance distribution of these birds in their Mediterranean wintering grounds.
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| 33. |
- van Noordwijk, AJ, et al.
(författare)
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A framework for the study of genetic variation in migratory behaviour
- 2006
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Ingår i: Journal of Ornithology. - : Springer Science and Business Media LLC. - 2193-7192 .- 2193-7206. ; 147:2, s. 221-233
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Evolutionary change results from selection acting on genetic variation. For migration to be successful, many different aspects of an animal's physiology and behaviour need to function in a co-coordinated way. Changes in one migratory trait are therefore likely to be accompanied by changes in other migratory and life-history traits. At present, we have some knowledge of the pressures that operate at the various stages of migration, but we know very little about the extent of genetic variation in various aspects of the migratory syndrome. As a consequence, our ability to predict which species is capable of what kind of evolutionary change, and at which rate, is limited. Here, we review how our evolutionary understanding of migration may benefit from taking a quantitative-genetic approach and present a framework for studying the causes of phenotypic variation. We review past research, that has mainly studied single migratory traits in captive birds, and discuss how this work could be extended to study genetic variation in the wild and to account for genetic correlations and correlated selection. In the future, reaction-norm approaches may become very important, as they allow the study of genetic and environmental effects on phenotypic expression within a single framework, as well as of their interactions. We advocate making more use of repeated measurements on single individuals to study the causes of among-individual variation in the wild, as they are easier to obtain than data on relatives and can provide valuable information for identifying and selecting traits. This approach will be particularly informative if it involves systematic testing of individuals under different environmental conditions. We propose extending this research agenda by using optimality models to predict levels of variation and covariation among traits and constraints. This may help us to select traits in which we might expect genetic variation, and to identify the most informative environmental axes. We also recommend an expansion of the passerine model, as this model does not apply to birds, like geese, where cultural transmission of spatio-temporal information is an important determinant of migration patterns and their variation.
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