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Jukka T. Forsman - One of the best experts on this subject based on the ideXlab platform.
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Flycatchers Copy Conspecifics in Nest-Site Selection but Neither Personal Experience nor Frequency of Tutors Have an Effect
2020Co-Authors: Tuomo Jaakkonen, Jukka T. Forsman, Annemari Kari, Stephen C PrattAbstract:Abstract Using the behavior of others in guiding one's own behavior is a common strategy in animals. The prevailing theory predicts that young age and the inexperience of an individual are expected to increase the probability of adopting the behaviors of others. Also, the most common behavior in the population should be copied. Here, we tested the above predictions by examining social information use in the selection of nest-site features with a field experiment using a wild cavity nesting bird, the collared Flycatcher (Ficedula albicollis). We used an experimental design in which geometric symbols depict nestsite features. By manipulating the apparent symbol choices of early settled individuals and monitoring the choices of later arriving birds, we can study social information use without bias from learned or innate preferences. Flycatchers were found to use social information in the selection of nest-site features, with about 60% of the population preferring the manipulated conspecific choices. However, age and experience as explanatory factors suggested by the social information use theory did not explain the choices. The present result, in concert with earlier similar experiments, implies that Flycatchers may in some situations rely more on interspecific information in the selection of nest-site characteristics
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Interspecific information on predation risk affects nest site choice in a passerine bird
'Springer Science and Business Media LLC', 2018Co-Authors: Jere Tolvanen, Jannetuomas Seppanen, Mikko Mönkkönen, Robert L. Thomson, Hannu Ylönen, Jukka T. ForsmanAbstract:Abstract Background Breeding site choice constitutes an important part of the species niche. Nest predation affects breeding site choice, and has been suggested to drive niche segregation and local coexistence of species. Interspecific social information use may, in turn, result in copying or rejection of heterospecific niche characteristics and thus affect realized niche overlap between species. We tested experimentally whether a migratory bird, the pied Flycatcher Ficedula hypoleuca, collects information about nest predation risk from indirect cues of predators visiting nests of heterospecific birds. Furthermore, we investigated whether the migratory birds can associate such information with a specific nest site characteristic and generalize the information to their own nest site choice. Results Our results demonstrate that Flycatchers can use the fate of heterospecific nesting attempts in their own nest site choice, but do so selectively. Young Flycatcher females, when making the decision quickly, associated the fate of an artificial nest with nest-site characteristics and avoided the characteristic associated with higher nest predation risk. Conclusions Copying nest site choices of successful heterospecifics, and avoiding choices which led to failed attempts, may amplify or counter effects of nest predation on niche overlap, with important consequences for between-species niche divergence-convergence dynamics, species coexistence and predator-prey interactions
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the past and the present in decision making the use of conspecific and heterospecific cues in nest site selection
Ecology, 2014Co-Authors: Sami M. Kivelä, Jannetuomas Seppanen, Mikko Mönkkönen, Otso Ovaskainen, Blandine Doligez, Lars Gustafsson, Jukka T. ForsmanAbstract:Nest site selection significantly affects fitness, so adaptations for assessment of the qualities of available sites are expected. The assessment may be based on personal or social information, the latter referring to the observed location and performance of both conspecific and heterospecific individuals. Contrary to large-scale breeding habitat selection, small-scale nest site selection within habitat patches is insufficiently understood. We analyzed nest site selection in the migratory Collared Flycatcher Ficedula albicollis in relation to present and past cues provided by conspecifics and by resident tits within habitat patches by using long-term data. Collared Flycatchers preferred nest boxes that were occupied by conspecifics in the previous year. This preference was strongest in breeding pairs where both individuals bred in the same forest patch in the previous year. The results also suggest preference for nest boxes close to boxes where conspecifics had a high breeding success in the previous year, and for nest boxes which are presently surrounded by a high number of breeding Great Tits Parus major. The results indicate social information use in nest site selection at a small spatial scale, where Collared Flycatchers use conspecific cues with a time lag of one year and heterospecific cues instantly.
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competitor density cues for habitat quality facilitating habitat selection and investment decisions
Behavioral Ecology, 2008Co-Authors: Jukka T. Forsman, Marten B Hjernquist, Jenni Taipale, Lars GustafssonAbstract:The theory of species coexistence predicts avoidance between species that compete for similar resources. Recent studies, however, have suggested that facilitation is also possible if competitor density provides information about resources. Optimal solution to trade-off between competition and facilitation is predicted to occur at intermediate competitor densities. We tested this hypothesis by experimentally creating a density range of resident tit species (Parus spp.), and measured the response of a competitively subordinate migratory bird, the collared Flycatcher (Ficedula albicollis) in terms of habitat preference (settlement order and density), offspring investment (clutch size and primary sex ratio of offspring), and reproductive success (number and condition of nestlings). We show that most habitat choice and investment decisions of Flycatchers were unimodally related to tit density, whereas reproductive success decreased linearly with increasing density. Flycatchers thus made mismatched investment decisions at the artificial tit densities because manipulation disassociated the natural correlation between habitat quality and population density. Apparently low and high tit densities were perceived as indication of poor quality habitat in terms of low amount or quality of resources/high mortality risk and high costs of competition, respectively. This demonstrates that competitor density can be used in assessing overall habitat quality in habitat selection and offspring investment decisions, integrating information on resources and competition.
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positive fitness consequences of interspecific interaction with a potential competitor
Proceedings of The Royal Society B: Biological Sciences, 2002Co-Authors: Jukka T. Forsman, Jannetuomas Seppanen, Mikko MönkkönenAbstract:The coexistence of species sharing mutual resources is usually thought to be limited by negative processes such as interspecific competition. This is because an overlap in resource use leads to negative fitness consequences, and traits favouring avoidance of potential competitors, for example in habitat selection, are therefore selected for. However, species interactions are acknowledged to vary from negative (competition) to mutualism, although empirical evidence for positive interspecific interactions from natural communities of other than plants and sessile animals is scarce. Here, we experimentally examined the habitat selection and its fitness consequences of a migrant bird, the pied Flycatcher (Ficedula hypoleuca), in relation to the presence of competitively superior birds, resident titmice (Parus spp.). Experiments were conducted on two spatial scales: landscape and nest-site scale. We demonstrate that pied Flycatchers were attracted to and accrued fitness benefits from the presence of titmice. Flycatchers breeding in tight association with titmice initiated breeding earlier, had larger broods and heavier young than solitarily breeding Flycatchers. This paradoxical result indicates that species interactions may switch from negative to positive and that the coexistence of species is not always restricted by negative costs caused by other species.
Lars Gustafsson - One of the best experts on this subject based on the ideXlab platform.
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Breeding consequences of flavivirus infection in the collared Flycatcher.
BMC evolutionary biology, 2018Co-Authors: Tanja M. Strand, Åke Lundkvist, Bjorn R. Olsen, Lars GustafssonAbstract:The breeding consequences of virus infections have rarely been studied in avian natural breeding populations. In this paper we investigated the links between humoral immunity following a natural flavivirus infection and reproduction in a wild bird population of collared Flycatcher (Ficedula albicollis). We analyzed plasma from 744 birds for antibodies and correlated these results to a number of reproductive components. Nearly one third (27.8%) of the sampled collared Flycatchers were found seropositive for flavivirus. Males had significantly more frequently flavivirus antibodies (32.3%) than females (25.1%). Seropositive females differed significantly from seronegative females in four traits: they had earlier lay date, higher body weight, higher survival rate and were older than seronegative females. The females did not differ in clutch size, number of fledged young or number of recruited young. Seropositive males had female partners with earlier lay date, i.e. the males bred earlier and they also produced more fledged young than seronegative males. In contrast, the males did not differ in clutch size, number of recruited young, male weight, age or survival. Interestingly, seropositive males had larger ornament, forehead badge size, than seronegative males. Collared Flycatchers with an antibody response against flavivirus were more successful than birds with no antibody response, for any of the measured life history traits. The positive link between flavivirus antibody presence and life-history trait levels suggest that it is condition dependent in the collared Flycatcher.
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the past and the present in decision making the use of conspecific and heterospecific cues in nest site selection
Ecology, 2014Co-Authors: Sami M. Kivelä, Jannetuomas Seppanen, Mikko Mönkkönen, Otso Ovaskainen, Blandine Doligez, Lars Gustafsson, Jukka T. ForsmanAbstract:Nest site selection significantly affects fitness, so adaptations for assessment of the qualities of available sites are expected. The assessment may be based on personal or social information, the latter referring to the observed location and performance of both conspecific and heterospecific individuals. Contrary to large-scale breeding habitat selection, small-scale nest site selection within habitat patches is insufficiently understood. We analyzed nest site selection in the migratory Collared Flycatcher Ficedula albicollis in relation to present and past cues provided by conspecifics and by resident tits within habitat patches by using long-term data. Collared Flycatchers preferred nest boxes that were occupied by conspecifics in the previous year. This preference was strongest in breeding pairs where both individuals bred in the same forest patch in the previous year. The results also suggest preference for nest boxes close to boxes where conspecifics had a high breeding success in the previous year, and for nest boxes which are presently surrounded by a high number of breeding Great Tits Parus major. The results indicate social information use in nest site selection at a small spatial scale, where Collared Flycatchers use conspecific cues with a time lag of one year and heterospecific cues instantly.
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a gene based genetic linkage map of the collared Flycatcher ficedula albicollis reveals extensive synteny and gene order conservation during 100 million years of avian evolution
Genetics, 2008Co-Authors: Niclas Backstrom, Lars Gustafsson, Nikoletta Karaiskou, Erica H Leder, Craig R Primmer, Anna Qvarnstrom, Hans EllegrenAbstract:By taking advantage of a recently developed reference marker set for avian genome analysis we have constructed a gene-based genetic map of the collared Flycatcher, an important “ecological model” for studies of life-history evolution, sexual selection, speciation, and quantitative genetics. A pedigree of 322 birds from a natural population was genotyped for 384 single nucleotide polymorphisms (SNPs) from 170 protein-coding genes and 71 microsatellites. Altogether, 147 gene markers and 64 microsatellites form 33 linkage groups with a total genetic distance of 1787 cM. Male recombination rates are, on average, 22% higher than female rates (total distance 1982 vs. 1627 cM). The ability to anchor the collared Flycatcher map with the chicken genome via the gene-based SNPs revealed an extraordinary degree of both synteny and gene-order conservation during avian evolution. The great majority of chicken chromosomes correspond to a single linkage group in collared Flycatchers, with only a few cases of inter- and intrachromosomal rearrangements. The rate of chromosomal diversification, fissions/fusions, and inversions combined is thus considerably lower in birds (0.05/MY) than in mammals (0.6–2.0/MY). A dearth of repeat elements, known to promote chromosomal breakage, in avian genomes may contribute to their stability. The degree of genome stability is likely to have important consequences for general evolutionary patterns and may explain, for example, the comparatively slow rate by which genetic incompatibility among lineages of birds evolves.
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competitor density cues for habitat quality facilitating habitat selection and investment decisions
Behavioral Ecology, 2008Co-Authors: Jukka T. Forsman, Marten B Hjernquist, Jenni Taipale, Lars GustafssonAbstract:The theory of species coexistence predicts avoidance between species that compete for similar resources. Recent studies, however, have suggested that facilitation is also possible if competitor density provides information about resources. Optimal solution to trade-off between competition and facilitation is predicted to occur at intermediate competitor densities. We tested this hypothesis by experimentally creating a density range of resident tit species (Parus spp.), and measured the response of a competitively subordinate migratory bird, the collared Flycatcher (Ficedula albicollis) in terms of habitat preference (settlement order and density), offspring investment (clutch size and primary sex ratio of offspring), and reproductive success (number and condition of nestlings). We show that most habitat choice and investment decisions of Flycatchers were unimodally related to tit density, whereas reproductive success decreased linearly with increasing density. Flycatchers thus made mismatched investment decisions at the artificial tit densities because manipulation disassociated the natural correlation between habitat quality and population density. Apparently low and high tit densities were perceived as indication of poor quality habitat in terms of low amount or quality of resources/high mortality risk and high costs of competition, respectively. This demonstrates that competitor density can be used in assessing overall habitat quality in habitat selection and offspring investment decisions, integrating information on resources and competition.
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inter and intraspecific competition for nest holes in a population of the collared Flycatcher ficedula albicollis
Ibis, 2008Co-Authors: Lars GustafssonAbstract:Field experiments with nest boxes show that nest holes are a limiting factor on the local population size of the Collared Flycatcher Ficedula albicollis. When this limiting resource occurs with different types that are quality related there is intraspecific competition among males for the best nest boxes, with bigger males being the better competitors. Population dynamics of Great Tit Parus major and Blue Tit P. caeruleus when compared with Collared Flycatchers suggests that there is strong interspecific Competition for available nest holes. This is also shown by removal experiments.
Anna Qvarnstrom - One of the best experts on this subject based on the ideXlab platform.
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differences in incubation behaviour and niche separation of two competing Flycatcher species
Behavioral Ecology and Sociobiology, 2020Co-Authors: Murielle Alund, Eryn S Mcfarlane, Paivi M Sirkia, Tuuli Marjaana Koski, Anna QvarnstromAbstract:Food availability sets the stage for incubation behaviour of a female bird and thereby indirectly determines the nest temperature, which in turn affects development and metabolism of avian embryos. Changes in development and metabolism in turn are known to influence offspring’s ability to adjust to environmental changes later in life. However, few studies have investigated the role of interspecific differences in incubation behaviour in relation to niche separation between competing sibling species. We studied the effects of habitat quality (in terms of caterpillar availability) on incubation behaviour of two ecologically similar and closely related species, collared and pied Flycatchers (Ficedula albicollis and F. hypoleuca), in their hybrid zone on the island of Oland, Sweden. Even though both species prefer caterpillar-rich deciduous forests as nesting sites, collared Flycatchers, whose nestlings have higher energetic demands, are able to nest only in deciduous forests, whereas pied Flycatchers have more flexible habitat requirements. Overall, higher food availability was associated with increased nest attendance, higher incubation temperature and a lower number of foraging trips across species. In addition, collared Flycatchers had more frequent and shorter foraging trips across habitat types, allocated more heat to eggs and therefore maintained higher nest temperatures compared to pied Flycatchers. We argue that the higher heat allocation or the need to maintain a higher nest temperature for embryo development may constrain collared Flycatchers to focus on relatively more profitable prey. Our results highlight the importance of considering incubation behaviour in the context of understanding species differences in niche use. Niche separation plays an important role in mitigating effects of competition between closely related species. Whether species differences in incubation behaviour relate to differences in niche use remains unknown. We compared incubation behaviour of two sympatric Flycatcher species that differ in sensitivity to food availability. The competitively more dominant and larger species, the collared Flycatcher, whose nestlings are more sensitive to food shortages, made more frequent foraging trips but allocated more heat to eggs, leading to higher nest temperature despite lower nest attendance, compared to pied Flycatchers. These interspecific differences may be a result of differences in embryo sensitivity or female physiology and contribute to the niche separation between the species, which in turn can facilitate coexistence.
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difference in plasticity of resting metabolic rate the proximate explanation to different niche breadth in sympatric ficedula Flycatchers
Ecology and Evolution, 2018Co-Authors: Eryn S Mcfarlane, Murielle Alund, Paivi M Sirkia, Anna QvarnstromAbstract:Variation in relative fitness of competing recently formed species across heterogeneous environments promotes coexistence. However, the physiological traits mediating such variation in relative fitness have rarely been identified. Resting metabolic rate (RMR) is tightly associated with life history strategies, thermoregulation, diet use, and inhabited latitude and could therefore moderate differences in fitness responses to fluctuations in local environments, particularly when species have adapted to different climates in allopatry. We work in a long-term study of collared (Ficedula albicollis) and pied Flycatchers (Ficedula hypoleuca) in a recent hybrid zone located on the Swedish island of Oland in the Baltic Sea. Here, we explore whether differences in RMR match changes in relative performance of growing Flycatcher nestlings across environmental conditions using an experimental approach. The fitness of pied Flycatchers has previously been shown to be less sensitive to the mismatch between the peak in food abundance and nestling growth among late breeders. Here, we find that pied Flycatcher nestlings have lower RMR in response to higher ambient temperatures (associated with low food availability). We also find that experimentally relaxed nestling competition is associated with an increased RMR in this species. In contrast, collared Flycatcher nestlings did not vary their RMR in response to these environmental factors. Our results suggest that a more flexible nestling RMR in pied Flycatchers is responsible for the better adaptation of pied Flycatchers to the typical seasonal changes in food availability experienced in this hybrid zone. Generally, subtle physiological differences that have evolved when species were in allopatry may play an important role to patterns of competition, coexistence, or displacements between closely related species in secondary contact.
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inferring individual inbreeding and demographic history from segments of identity by descent in ficedula Flycatcher genome sequences
Genetics, 2017Co-Authors: Anna Qvarnstrom, Marty Kardos, Hans EllegrenAbstract:Individual inbreeding and historical demography can be estimated by analyzing runs of homozygosity (ROH), which are indicative of chromosomal segments of identity by descent (IBD). Such analyses have so far been rare in natural populations due to limited genomic resources. We analyzed ROH in whole genome sequences from 287 Ficedula Flycatchers representing four species, with the objectives of evaluating the causes of genome-wide variation in the abundance of ROH and inferring historical demography. ROH were clearly more abundant in genomic regions with low recombination rate. However, this pattern was substantially weaker when ROH were mapped using genetic rather than physical single nucleotide polymorphism (SNP) coordinates in the genome. Empirical results and simulations suggest that high ROH abundance in regions of low recombination was partly caused by increased power to detect the very long IBD segments typical of regions with a low recombination rate. Simulations also showed that hard selective sweeps (but not soft sweeps or background selection) likely contributed to variation in the abundance of ROH across the genome. Comparisons of the abundance of ROH among several study populations indicated that the Spanish pied Flycatcher population had the smallest historical effective population size (Ne) for this species, and that a putatively recently founded island (Baltic) population had the smallest historical Ne among the collared Flycatchers. Analysis of pairwise IBD in Baltic collared Flycatchers indicated that this population was founded <60 generations ago. This study provides a rare genomic glimpse into demographic history and the mechanisms underlying the genome-wide distribution of ROH.
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a high density scan of the z chromosome in ficedula Flycatchers reveals candidate loci for diversifying selection
Evolution, 2010Co-Authors: Niclas Backstrom, Anna Qvarnstrom, Glennpeter Saetre, Johan Lindell, Yu Zhang, Eleftheria Palkopoulou, Hans EllegrenAbstract:Theoretical and empirical data suggest that genes located on sex chromosomes may play an important role both for sexually selected traits and for traits involved in the build-up of hybrid incompatibilities. We investigated patterns of genetic variation in 73 genes located on the Z chromosomes of two species of the Flycatcher genus Ficedula, the pied Flycatcher and the collared Flycatcher. Sequence data were evaluated for signs of selection potentially related to genomic differentiation in these young sister species, which hybridize despite reduced fitness of hybrids. Seven loci were significantly more divergent between the two species than expected under neutrality and they also displayed reduced nucleotide diversity, consistent with having been influenced by directional selection. Two of the detected candidate regions contain genes that are associated with plumage coloration in birds. Plumage characteristics play an important role in species recognition in these Flycatchers suggesting that the detected genes may have been involved in the evolution of sexual isolation between the species.
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a gene based genetic linkage map of the collared Flycatcher ficedula albicollis reveals extensive synteny and gene order conservation during 100 million years of avian evolution
Genetics, 2008Co-Authors: Niclas Backstrom, Lars Gustafsson, Nikoletta Karaiskou, Erica H Leder, Craig R Primmer, Anna Qvarnstrom, Hans EllegrenAbstract:By taking advantage of a recently developed reference marker set for avian genome analysis we have constructed a gene-based genetic map of the collared Flycatcher, an important “ecological model” for studies of life-history evolution, sexual selection, speciation, and quantitative genetics. A pedigree of 322 birds from a natural population was genotyped for 384 single nucleotide polymorphisms (SNPs) from 170 protein-coding genes and 71 microsatellites. Altogether, 147 gene markers and 64 microsatellites form 33 linkage groups with a total genetic distance of 1787 cM. Male recombination rates are, on average, 22% higher than female rates (total distance 1982 vs. 1627 cM). The ability to anchor the collared Flycatcher map with the chicken genome via the gene-based SNPs revealed an extraordinary degree of both synteny and gene-order conservation during avian evolution. The great majority of chicken chromosomes correspond to a single linkage group in collared Flycatchers, with only a few cases of inter- and intrachromosomal rearrangements. The rate of chromosomal diversification, fissions/fusions, and inversions combined is thus considerably lower in birds (0.05/MY) than in mammals (0.6–2.0/MY). A dearth of repeat elements, known to promote chromosomal breakage, in avian genomes may contribute to their stability. The degree of genome stability is likely to have important consequences for general evolutionary patterns and may explain, for example, the comparatively slow rate by which genetic incompatibility among lineages of birds evolves.
Indrikis Krams - One of the best experts on this subject based on the ideXlab platform.
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phenological sensitivity to climate change is higher in resident than in migrant bird populations among european cavity breeders
Global Change Biology, 2018Co-Authors: Jelmer M Samplonius, Lenka Bartosova, E V Ivankina, Alexander V. Bushuev, Malcolm D Burgess, A B Kerimov, Tapio Eeva, Indrikis KramsAbstract:Abstract Many organisms adjust their reproductive phenology in response to climate change, but phenological sensitivity to temperature may vary between species. For example, resident and migratory birds have vastly different annual cycles, which can cause differential temperature sensitivity at the breeding grounds, and may affect competitive dynamics. Currently, however, adjustment to climate change in resident and migratory birds have been studied separately or at relatively small geographical scales with varying time series durations and methodologies. Here, we studied differential effects of temperature on resident and migratory birds using the mean egg laying initiation dates from 10 European nest box schemes between 1991 and 2015 that had data on at least one resident tit species and at least one migratory Flycatcher species. We found that both tits and Flycatchers advanced laying in response to spring warming, but resident tit populations advanced more strongly in relation to temperature increases than migratory Flycatchers. These different temperature responses have already led to a divergence in laying dates between tits and Flycatchers of on average 0.94 days per decade over the current study period. Interestingly, this divergence was stronger at lower latitudes where the interval between tit and Flycatcher phenology is smaller and winter conditions can be considered more favorable for resident birds. This could indicate that phenological adjustment to climate change by Flycatchers is increasingly hampered by competition with resident species. Indeed, we found that tit laying date had an additional effect on Flycatcher laying date after controlling for temperature, and this effect was strongest in areas with the shortest interval between both species groups. Combined, our results suggest that the differential effect of climate change on species groups with overlapping breeding ecology affects the phenological interval between them, potentially affecting interspecific interactions.
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geographic patterns of genetic differentiation and plumage colour variation are different in the pied Flycatcher ficedula hypoleuca
Molecular Ecology, 2009Co-Authors: Paula K Lehtonen, Indrikis Krams, Toni Laaksonen, Stanislav Bures, A V Artemyev, Eugen Belskii, Christiaan Both, A V Bushuev, Juan MorenoAbstract:The pied Flycatcher is one of the most phenotypically variable bird species in Europe. The geographic variation in phenotypes has often been attributed to spatial variation in selection regimes that is associated with the presence or absence of the congeneric collared Flycatcher. Spatial variation in phenotypes could however also be generated by spatially restricted gene flow and genetic drift. We examined the genetic population structure of pied Flycatchers across the breeding range and applied the phenotypic Q(ST) (P(ST))-F(ST) approach to detect indirect signals of divergent selection on dorsal plumage colouration in pied Flycatcher males. Allelic frequencies at neutral markers were found to significantly differ among populations breeding in central and southern Europe whereas northerly breeding pied Flycatchers were found to be one apparently panmictic group of individuals. Pairwise differences between phenotypic (P(ST)) and neutral genetic distances (F(ST)) were positively correlated after removing the most differentiated Spanish and Swiss populations from the analysis, suggesting that genetic drift may have contributed to the observed phenotypic differentiation in some parts of the pied Flycatcher breeding range. Differentiation in dorsal plumage colouration however greatly exceeded that observed at neutral genetic markers, which indicates that the observed pattern of phenotypic differentiation is unlikely to be solely maintained by restricted gene flow and genetic drift.
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experimental evidence of reciprocal altruism in the pied Flycatcher
Behavioral Ecology and Sociobiology, 2008Co-Authors: Indrikis Krams, Tatjana Krama, Kristine Igaune, Raivo MandAbstract:Although human behaviour abounds with reciprocal altruism, few examples exist documenting reciprocal altruism in animals. Recent non-experimental evidence suggests that reciprocal altruism may be more common in nature than previously documented. Here we present experimental evidence of mobbing behaviour, the joint assault on a predator in an attempt to drive it away, as reciprocal altruism in the breeding pied Flycatcher (Ficedula hypoleuca). Given a choice, pied Flycatchers assisted in mobbing initiated by co-operating neighbours and did not join in mobbing when initiated by conspecific neighbours which had defected from necessary assistance 1 h before. The results suggest the birds followed a ‘tit-for-tat’-like strategy and that mobbing behaviour of breeding birds may be explained in terms of reciprocal altruism.
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cost of mobbing call to breeding pied Flycatcher ficedula hypoleuca
Behavioral Ecology, 2005Co-Authors: Tatjana Krama, Indrikis KramsAbstract:Mobbing signals advertise the location of a stalking predator to all prey in an area and recruit them into the inspection aggregation. Such behavior usually causes the predator to move to another area. However, mobbing calls could be eavesdropped by other predators. Because the predation cost of mobbing calls is poorly known, we investigated whether the vocalizations of the mobbing pied Flycatcher, Ficedula hypoleuca, a small hole nesting passerine, increase the risk of nest predation. We used mobbing calls of pied Flycatchers to examine if they could lure predators such as the marten, Martes martes. This predator usually hunts by night and may locate its mobbing prey while resting nearby during the day. Within each of 56 experimental plots, from the top of one nest-box we played back mobbing sounds of pied Flycatchers, whereas blank tapes were played from the top of another nestbox. The trials with mobbing calls were carried out before sunset. We put pieces of recently abandoned nests of pied Flycatchers and a quail, Coturnix coturnix, egg into each of the nest-boxes. Nest-boxes with playbacks of mobbing calls were depredated by martens significantly more than were nest-boxes with blank tapes. The results of the present study indicate that repeated conspicuous mobbing calls may carry a significant cost for birds during the breeding season. Key words: antipredator behavior, Ficedula hypoleuca, mobbing calls, mobbing costs, pied Flycatcher. [Behav Ecol]
Hans Ellegren - One of the best experts on this subject based on the ideXlab platform.
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positive selection plays a major role in shaping signatures of differentiation across the genomic landscape of two independent ficedula Flycatcher species pairs
Evolution, 2021Co-Authors: Madeline A Chase, Hans Ellegren, Carina F MugalAbstract:A current debate within population genomics surrounds the relevance of patterns of genomic differentiation between closely related species for our understanding of adaptation and speciation. Mounting evidence across many taxa suggests that the same genomic regions repeatedly develop elevated differentiation in independent species pairs. These regions often coincide with high gene density and/or low recombination, leading to the hypothesis that the genomic differentiation landscape mostly reflects a history of background selection, and reveals little about adaptation or speciation. A comparative genomics approach with multiple independent species pairs at a timescale where gene flow and ILS are negligible permits investigating whether different evolutionary processes are responsible for generating lineage-specific versus shared patterns of species differentiation. We use whole-genome resequencing data of 195 individuals from four Ficedula Flycatcher species comprising two independent species pairs: collared and pied Flycatchers, and red-breasted and taiga Flycatchers. We found that both shared and lineage-specific FST peaks could partially be explained by selective sweeps, with recurrent selection likely to underlie shared signatures of selection, whereas indirect evidence supports a role of recombination landscape evolution in driving lineage-specific signatures of selection. This work therefore provides evidence for an interplay of positive selection and recombination to genomic landscape evolution.
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inferring individual inbreeding and demographic history from segments of identity by descent in ficedula Flycatcher genome sequences
Genetics, 2017Co-Authors: Anna Qvarnstrom, Marty Kardos, Hans EllegrenAbstract:Individual inbreeding and historical demography can be estimated by analyzing runs of homozygosity (ROH), which are indicative of chromosomal segments of identity by descent (IBD). Such analyses have so far been rare in natural populations due to limited genomic resources. We analyzed ROH in whole genome sequences from 287 Ficedula Flycatchers representing four species, with the objectives of evaluating the causes of genome-wide variation in the abundance of ROH and inferring historical demography. ROH were clearly more abundant in genomic regions with low recombination rate. However, this pattern was substantially weaker when ROH were mapped using genetic rather than physical single nucleotide polymorphism (SNP) coordinates in the genome. Empirical results and simulations suggest that high ROH abundance in regions of low recombination was partly caused by increased power to detect the very long IBD segments typical of regions with a low recombination rate. Simulations also showed that hard selective sweeps (but not soft sweeps or background selection) likely contributed to variation in the abundance of ROH across the genome. Comparisons of the abundance of ROH among several study populations indicated that the Spanish pied Flycatcher population had the smallest historical effective population size (Ne) for this species, and that a putatively recently founded island (Baltic) population had the smallest historical Ne among the collared Flycatchers. Analysis of pairwise IBD in Baltic collared Flycatchers indicated that this population was founded <60 generations ago. This study provides a rare genomic glimpse into demographic history and the mechanisms underlying the genome-wide distribution of ROH.
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the genomic landscape of species divergence in ficedula Flycatchers
Nature, 2012Co-Authors: Hans Ellegren, Niclas Backstrom, Linnea Smeds, Reto Burri, Pall Olason, Takeshi Kawakami, Axel Kunstner, Hannu Makinen, Krystyna NadachowskabrzyskaAbstract:The results of sequencing the collared Flycatcher genome, and re-sequencing population samples from this species and its sister species, the pied Flycatcher, reveal the existence of areas of high sequence divergence compared to background levels, and suggest that complex repeat structures may drive species divergence and that sex chromosomes and autosomes are at different stages of speciation. Flycatchers are important models for speciation. To provide genome-wide insight into the divergence that occurred between lineages during speciation, Hans Ellegren et al. have sequenced the pied Flycatcher genome and re-sequenced population samples from this and another species. The results reveal the existence of 'divergence islands' — with fiftyfold higher sequence divergence than the genomic background — non-randomly distributed across the genome. Natural selection acting in both lineages drives divergence in these regions. The authors also report the unexpected observation that targets for selection may not be genes, and may instead be centromeric and telomeric repeats. Unravelling the genomic landscape of divergence between lineages is key to understanding speciation1. The naturally hybridizing collared Flycatcher and pied Flycatcher are important avian speciation models2,3,4,5,6,7 that show pre- as well as postzygotic isolation8,9. We sequenced and assembled the 1.1-Gb Flycatcher genome, physically mapped the assembly to chromosomes using a low-density linkage map10 and re-sequenced population samples of each species. Here we show that the genomic landscape of species differentiation is highly heterogeneous with approximately 50 ‘divergence islands’ showing up to 50-fold higher sequence divergence than the genomic background. These non-randomly distributed islands, with between one and three regions of elevated divergence per chromosome irrespective of chromosome size, are characterized by reduced levels of nucleotide diversity, skewed allele-frequency spectra, elevated levels of linkage disequilibrium and reduced proportions of shared polymorphisms in both species, indicative of parallel episodes of selection. Proximity of divergence peaks to genomic regions resistant to sequence assembly, potentially including centromeres and telomeres, indicate that complex repeat structures may drive species divergence. A much higher background level of species divergence of the Z chromosome, and a lower proportion of shared polymorphisms, indicate that sex chromosomes and autosomes are at different stages of speciation. This study provides a roadmap to the emerging field of speciation genomics.
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a high density scan of the z chromosome in ficedula Flycatchers reveals candidate loci for diversifying selection
Evolution, 2010Co-Authors: Niclas Backstrom, Anna Qvarnstrom, Glennpeter Saetre, Johan Lindell, Yu Zhang, Eleftheria Palkopoulou, Hans EllegrenAbstract:Theoretical and empirical data suggest that genes located on sex chromosomes may play an important role both for sexually selected traits and for traits involved in the build-up of hybrid incompatibilities. We investigated patterns of genetic variation in 73 genes located on the Z chromosomes of two species of the Flycatcher genus Ficedula, the pied Flycatcher and the collared Flycatcher. Sequence data were evaluated for signs of selection potentially related to genomic differentiation in these young sister species, which hybridize despite reduced fitness of hybrids. Seven loci were significantly more divergent between the two species than expected under neutrality and they also displayed reduced nucleotide diversity, consistent with having been influenced by directional selection. Two of the detected candidate regions contain genes that are associated with plumage coloration in birds. Plumage characteristics play an important role in species recognition in these Flycatchers suggesting that the detected genes may have been involved in the evolution of sexual isolation between the species.
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speciation introgressive hybridization and nonlinear rate of molecular evolution in Flycatchers
Molecular Ecology, 2008Co-Authors: Glennpeter Saetre, Craig R Primmer, Thomas Borge, Jon Haavie, Ben C Sheldon, Johan Lindell, Truls Moum, Arild Johnsen, Hans EllegrenAbstract:Evolutionary history of Muscicapidae Flycatchers is inferred from nuclear and mitochondrial DNA (mtDNA) sequence comparisons and population genetic analysis of nuclear and mtDNA markers. Phylogenetic reconstruction based on sequences from the two genomes yielded similar trees with respect to the order at which the species split off. However, the genetic distances fitted a nonlinear, polynomial model reflecting diminishing divergence rate of the mtDNA sequences compared to the nuclear DNA sequences. This could be explained by Haldane's rule because genetic isolation might evolve more rapidly on the mitochondrial rather than the nuclear genome in birds. This is because hybrid sterility of the heterogametic sex (females) would predate that of the homogametic sex (males), leading to sex biased introgression of nuclear genes. Analyses of present hybrid zones of pied (Ficedula hypoleuca) and collared Flycatchers (F. albicollis) may indicate a slight sexual bias in rate of introgression, but the introgression rates were too low to allow proper statistical analyses. It is suggested, however, that the observed deviation from linearity can be explained by a more rapid mutational saturation of the mtDNA sequences than of the nuclear DNA sequences, as supported by analyses of third codon position transversions at two protein coding mtDNA genes. A phylogeographic scenario for the black and white Flycatcher species is suggested based on interpretation of the genetic data obtained. Four species appear to have diverged from a common ancestor relatively simultaneously during the Pleistocene. After the last glaciation period, pied and collared Flycatchers expanded their breeding ranges and eventually came into secondary contact in Central and Eastern Europe and on the Baltic Isles.
