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Stuart B. Piertney - One of the best experts on this subject based on the ideXlab platform.
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Adaptive and neutral genetic differentiation among Scottish and endangered Irish red grouse (lagopus lagopus scotica)
Conservation Genetics, 2016Co-Authors: Yvonne Meyer-lucht, Marianne C. James, Stuart B. Piertney, Kevin P. Mulder, Barry J. Mcmahon, Kieran Buckley, Jacob HöglundAbstract:Studying patterns of intra-specific genetic variation among populations allows for a better understanding of population structure and local adaptation. However, those patterns may differ according to the genetic markers applied, as neutral genetic markers reflect demographic processes and random genetic drift, whereas adaptive markers also carry the footprint of selection. In combination, neutral and adaptive genetic markers permit to assess the relative roles of drift and selection in shaping population structure. Among the best understood adaptive genetic loci are the genes of the major histocompatibility complex (MHC). We here study variation and differentiation at neutral SNP markers and MHC class II genes in red grouse (lagopus lagopus scotica) from Ireland and Scotland. Irish red grouse populations are fragmented and drastically declining, but red grouse are abundant in Scotland. We find evidence for positive selection acting on the MHC genes and variation in MHC gene copy numbers among Irish individuals. Furthermore, there was significant population differentiation among red grouse from Ireland and Scotland at the neutral SNP markers (FST = 0.084) and the MHC-BLB genes (FST: BLB1 = 0.116, BLB2 = 0.090, BLB3 = 0.104). Differentiation at the MHC-BLB1 was significantly higher than at the neutral SNP markers, suggesting that selection plays an important role in shaping MHC variation, in addition to genetic drift. We speculate that the observed differentiation pattern might be due to local adaptation to different parasite regimes. These findings have strong conservation implications and we advise against the introduction of Scottish red grouse to supplement Irish populations.
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the role of parasite driven selection in shaping landscape genomic structure in red grouse lagopus lagopus scotica
Molecular Ecology, 2016Co-Authors: Marius A. Wenzel, Stephen M Redpath, Marianne C. James, Alex Douglas, Stuart B. PiertneyAbstract:Landscape genomics promises to provide novel insights into how neutral and adaptive processes shape genome-wide variation within and among populations. However, there has been little emphasis on examining whether individual-based phenotype-genotype relationships derived from approaches such as genome-wide association (GWAS) manifest themselves as a population-level signature of selection in a landscape context. The two may prove irreconcilable as individual-level patterns become diluted by high levels of gene flow and complex phenotypic or environmental heterogeneity. We illustrate this issue with a case study that examines the role of the highly prevalent gastrointestinal nematode Trichostrongylus tenuis in shaping genomic signatures of selection in red grouse (lagopus lagopus scotica). Individual-level GWAS involving 384 SNPs has previously identified five SNPs that explain variation in T. tenuis burden. Here, we examine whether these same SNPs display population-level relationships between T. tenuis burden and genetic structure across a small-scale landscape of 21 sites with heterogeneous parasite pressure. Moreover, we identify adaptive SNPs showing signatures of directional selection using F(ST) outlier analysis and relate population- and individual-level patterns of multilocus neutral and adaptive genetic structure to T. tenuis burden. The five candidate SNPs for parasite-driven selection were neither associated with T. tenuis burden on a population level, nor under directional selection. Similarly, there was no evidence of parasite-driven selection in SNPs identified as candidates for directional selection. We discuss these results in the context of red grouse ecology and highlight the broader consequences for the utility of landscape genomics approaches for identifying signatures of selection.
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Identification and characterisation of 17 polymorphic candidate genes for response to parasitic nematode (Trichostrongylus tenuis) infection in red grouse (lagopus lagopus scotica)
Conservation Genetics Resources, 2015Co-Authors: Marius A. Wenzel, Lucy M. I. Webster, Steve Paterson, Stuart B. PiertneyAbstract:The red grouse ( lagopus lagopus scotica ) is an economically important game bird species endemic to the upland heather moors of the British Isles, where its conservation status is “amber” due to long-term declines in breeding populations. One major driver of grouse population ecology is chronic infection by the highly prevalent, gastrointestinal parasitic nematode Trichostrongylus tenuis . Here, we outline the identification and characterisation of 17 candidate genes for the physiological response of red grouse to parasite infection, developed de novo from functional and genetic analysis of grouse transcriptomic and genomic resources. These genes capture broad physiological functions, including immune system processes, xenobiotics detoxification, oxidative balance, metabolism and cell cycle regulation. All genes were polymorphic at the landscape scale in north-east Scotland, indicating great utility for characterising the causes and consequences of spatio-temporal genetic variation in relation to parasite-mediated eco-evolutionary processes in red grouse populations.
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in silico identification and characterisation of 17 polymorphic anonymous non coding sequence markers anms for red grouse lagopus lagopus scotica
Conservation Genetics Resources, 2015Co-Authors: Marius A. Wenzel, Stuart B. PiertneyAbstract:Anonymous non-coding sequence markers (ANMs) are powerful neutral genetic markers with great utility in phylogeography, population genetics and population genomics. Developing ANMs has previously relied on sequencing random fragments of genomic DNA in the target species and then querying bioinformatics databases to identify unannotated, putatively neutral fragments. Here, we describe an alternative in silico approach that is based on identifying large unannotated genomic regions in model species to provide a priori neutral targets for candidate ANMs that are remote from exonic regions. We illustrate this approach by developing a set of 17 polymorphic ANMs for red grouse (lagopus lagopus scotica) from c. 1 Mbp non-coding chromosome regions of chicken, turkey and zebrafinch genomes. This pipeline presents a powerful and efficient approach when appropriate model genomes are available for the target species of interest.
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fine scale population epigenetic structure in relation to gastrointestinal parasite load in red grouse lagopus lagopus scotica
Molecular Ecology, 2014Co-Authors: Marius A. Wenzel, Stuart B. PiertneyAbstract:Epigenetic modification of cytosine methylation states can be elicited by environmental stresses and may be a key process affecting phenotypic plasticity and adaptation. Parasites are potent stressors with profound physiological and ecological effects on their host, but there is little understanding in how parasites may influence host methylation states. Here, we estimate epigenetic diversity and differentiation among 21 populations of red grouse (lagopus lagopus scotica) in north-east Scotland and test for association of gastrointestinal parasite load (caecal nematode Trichostrongylus tenuis) with hepatic genome-wide and locus-specific methylation states. Following methylation-sensitive AFLP (MSAP), 129 bands, representing 73 methylation-susceptible and 56 nonmethylated epiloci, were scored across 234 individuals. The populations differed significantly in genome-wide methylation levels and were also significantly epigenetically (FSC = 0.0227; P < 0.001) and genetically (FSC = 0.0058; P < 0.001) differentiated. Parasite load was not associated with either genome-wide methylation levels or epigenetic differentiation. Instead, we found eight disproportionately differentiated epilocus-specific methylation states (FST outliers) using bayescan software and significant positive and negative association of 35 methylation states with parasite load from bespoke generalized estimating equations (GEE), simple logistic regression (sam) and Bayesian environmental analysis (bayenv2). Following Sanger sequencing, genome mapping and geneontology (go) annotation, some of these epiloci were linked to genes involved in regulation of cell cycle, signalling, metabolism, immune system and notably rRNA methylation, histone acetylation and small RNAs. These findings demonstrate an epigenetic signature of parasite load in populations of a wild bird and suggest intriguing physiological effects of parasite-associated cytosine methylation.
Stephen M Redpath - One of the best experts on this subject based on the ideXlab platform.
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the role of parasite driven selection in shaping landscape genomic structure in red grouse lagopus lagopus scotica
Molecular Ecology, 2016Co-Authors: Marius A. Wenzel, Stephen M Redpath, Marianne C. James, Alex Douglas, Stuart B. PiertneyAbstract:Landscape genomics promises to provide novel insights into how neutral and adaptive processes shape genome-wide variation within and among populations. However, there has been little emphasis on examining whether individual-based phenotype-genotype relationships derived from approaches such as genome-wide association (GWAS) manifest themselves as a population-level signature of selection in a landscape context. The two may prove irreconcilable as individual-level patterns become diluted by high levels of gene flow and complex phenotypic or environmental heterogeneity. We illustrate this issue with a case study that examines the role of the highly prevalent gastrointestinal nematode Trichostrongylus tenuis in shaping genomic signatures of selection in red grouse (lagopus lagopus scotica). Individual-level GWAS involving 384 SNPs has previously identified five SNPs that explain variation in T. tenuis burden. Here, we examine whether these same SNPs display population-level relationships between T. tenuis burden and genetic structure across a small-scale landscape of 21 sites with heterogeneous parasite pressure. Moreover, we identify adaptive SNPs showing signatures of directional selection using F(ST) outlier analysis and relate population- and individual-level patterns of multilocus neutral and adaptive genetic structure to T. tenuis burden. The five candidate SNPs for parasite-driven selection were neither associated with T. tenuis burden on a population level, nor under directional selection. Similarly, there was no evidence of parasite-driven selection in SNPs identified as candidates for directional selection. We discuss these results in the context of red grouse ecology and highlight the broader consequences for the utility of landscape genomics approaches for identifying signatures of selection.
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working with stakeholders to reduce conflict modelling the impact of varying hen harrier circus cyaneus densities on red grouse lagopus lagopus populations
Journal of Applied Ecology, 2014Co-Authors: David A. Elston, Luigi Spezia, Dave Baines, Stephen M RedpathAbstract:Summary 1. Conflict management is difficult and may benefit from scientists working closely with stakeholders. We worked with conservation and moorland management interests, to consider the potential use of a quota system to address the long-standing conflict arising from hen harrier Circus cyaneus predation on red grouse lagopus lagopus scoticus. 2. We modelled the impact of different harrier densities on grouse populations using a stochastic population dynamics model to inform the debate over the consequences of a quota system. The stakeholders commissioned the work and agreed on the underlying principles, the data sets and the approach. 3. The model covers the recovery phase from low grouse densities to a level at which driven shooting can recommence, as this phase is of paramount concern to the managers of grouse moors. 4. The model incorporated uncertainty in parameter values as well as for temporal and spatial variation in demographic rates. Multiple runs of the model enabled us to construct probability distributions, both for the population sizes in the first 2 years following cyclic lows in the grouse populations and for the number of years to recommencement of driven grouse shooting. 5. The model results quantified the extent to which high densities of harriers pose challenges for grouse management. At harrier densities of or below 0� 025 km 2 , harrier impacts were predicted to reduce autumn grouse densities by <10%, suggesting that a quota scheme could theoretically support coexistence between grouse shooting and harrier conservation. 6. Synthesis and applications. Conflict management requires dialogue between conflicting parties and can benefit from objective inputs from scientists using an agreed evidence base and transparent derivation of relevant information from that evidence base. By discussing the principles of model development and eligibility of data sets with a stakeholder group in advance of producing model results, we achieved buy-in from all parties involved. Our model informs the debate: whether this additional information will lead to the development and testing of a quota system in practice remains to be seen.
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Working with stakeholders to reduce conflict - modelling the impact of varying hen harrier Circus cyaneus densities on red grouse lagopus lagopus populations
Journal of Applied Ecology, 2014Co-Authors: David A. Elston, Luigi Spezia, Dave Baines, Stephen M RedpathAbstract:Summary 1. Conflict management is difficult and may benefit from scientists working closely with stakeholders. We worked with conservation and moorland management interests, to consider the potential use of a quota system to address the long-standing conflict arising from hen harrier Circus cyaneus predation on red grouse lagopus lagopus scoticus. 2. We modelled the impact of different harrier densities on grouse populations using a stochastic population dynamics model to inform the debate over the consequences of a quota system. The stakeholders commissioned the work and agreed on the underlying principles, the data sets and the approach. 3. The model covers the recovery phase from low grouse densities to a level at which driven shooting can recommence, as this phase is of paramount concern to the managers of grouse moors. 4. The model incorporated uncertainty in parameter values as well as for temporal and spatial variation in demographic rates. Multiple runs of the model enabled us to construct probability distributions, both for the population sizes in the first 2 years following cyclic lows in the grouse populations and for the number of years to recommencement of driven grouse shooting. 5. The model results quantified the extent to which high densities of harriers pose challenges for grouse management. At harrier densities of or below 0� 025 km 2 , harrier impacts were predicted to reduce autumn grouse densities by
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Insights into population ecology from long-term studies of red grouse lagopus lagopus scoticus.
Journal of Animal Ecology, 2013Co-Authors: Jesús Martínez-padilla, Stephen M Redpath, Mohammed Zeineddine, Francois MougeotAbstract:Summary Long-term studies have been the backbone of population ecology. The red grouse lagopus lagopus scoticus is one species that has contributed widely to this field since the 1950s. This paper reviews the trajectory and profound impact that these studies have had. Red grouse research has combined long-term studies of marked individuals with demographic studies over wide geographical areas and replicated individual- and population-level manipulations. A main focus has been on understanding the causes of population cycles in red grouse, and in particular the relative importance of intrinsic (behaviour) and extrinsic (climate, food limitation and parasite) mechanisms. Separate studies conducted in different regions initially proposed either the nematode parasite Trichostrongylus tenuis or changes in male aggressiveness in autumn as drivers of population cycles. More recent experiments suggest that parasites are not a necessary cause for cycles and have highlighted that behavioural and parasite-mediated mechanisms are interrelated. Long-term experiments show that parasites and aggressiveness interact. Two outstanding questions remain to be tested experimentally. First, what intrinsic mechanism causes temporal variation in patterns of male aggressiveness? The current favoured mechanism is related to patterns of kin structuring although there are alternative hypotheses. Second, how do the dual, interacting mechanisms, affect population dynamics? Red grouse studies have had an important impact on the field of population ecology, in particular through highlighting: (1) the impact of parasites on populations; (2) the role of intrinsic mechanisms in cyclic dynamics and (3) the need to consider multiple, interacting mechanisms.
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Temporal changes in kin structure through a population cycle in a territorial bird, the red grouse lagopus lagopus scoticus
Molecular Ecology, 2008Co-Authors: Stuart B. Piertney, F Leckie, Francois Mougeot, Andrew D. C. Maccoll, Xavier Lambin, John F. Dallas, Philip J. Bacon, Paul A Racey, Kerry Lock, Stephen M RedpathAbstract:Populations of red grouse (lagopus lagopus scoticus) undergo regular multiannual cycles in abundance. The ‘kinship hypothesis’ posits that such cycles are caused by changes in kin structure among territorial males producing delayed density-dependent changes in aggressiveness, which in turn influence recruitment and regulate density. The kinship hypothesis makes several specific predictions about the levels of kinship, aggressiveness and recruitment through a population cycle: (i) kin structure will build up during the increase phase of a cycle, but break down prior to peak density; (ii) kin structure influences aggressiveness, such that there will be a negative relationship between kinship and aggressiveness over the years; (iii) as aggressiveness regulates recruitment and density, there will be a negative relationship between aggressiveness in one year and both recruitment and density in the next; (iv) as kin structure influences recruitment via an affect on aggressiveness, there will be a positive relationship between kinship in one year and recruitment the next. Here we test these predictions through the course of an 8-year cycle in a natural population of red grouse in northeast Scotland, using microsatellite DNA markers to resolve changing patterns of kin structure, and supra-orbital comb height of grouse as an index of aggressiveness. Both kin structure and aggressiveness were dynamic through the course of the cycle, and changing patterns were entirely consistent with the expectations of the kinship hypothesis. Results are discussed in relation to potential drivers of population regulation and implications of dynamic kin structure for population genetics.
Jacob Höglund - One of the best experts on this subject based on the ideXlab platform.
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Adaptive and neutral genetic differentiation among Scottish and endangered Irish red grouse (lagopus lagopus scotica)
Conservation Genetics, 2016Co-Authors: Yvonne Meyer-lucht, Marianne C. James, Stuart B. Piertney, Kevin P. Mulder, Barry J. Mcmahon, Kieran Buckley, Jacob HöglundAbstract:Studying patterns of intra-specific genetic variation among populations allows for a better understanding of population structure and local adaptation. However, those patterns may differ according to the genetic markers applied, as neutral genetic markers reflect demographic processes and random genetic drift, whereas adaptive markers also carry the footprint of selection. In combination, neutral and adaptive genetic markers permit to assess the relative roles of drift and selection in shaping population structure. Among the best understood adaptive genetic loci are the genes of the major histocompatibility complex (MHC). We here study variation and differentiation at neutral SNP markers and MHC class II genes in red grouse (lagopus lagopus scotica) from Ireland and Scotland. Irish red grouse populations are fragmented and drastically declining, but red grouse are abundant in Scotland. We find evidence for positive selection acting on the MHC genes and variation in MHC gene copy numbers among Irish individuals. Furthermore, there was significant population differentiation among red grouse from Ireland and Scotland at the neutral SNP markers (FST = 0.084) and the MHC-BLB genes (FST: BLB1 = 0.116, BLB2 = 0.090, BLB3 = 0.104). Differentiation at the MHC-BLB1 was significantly higher than at the neutral SNP markers, suggesting that selection plays an important role in shaping MHC variation, in addition to genetic drift. We speculate that the observed differentiation pattern might be due to local adaptation to different parasite regimes. These findings have strong conservation implications and we advise against the introduction of Scottish red grouse to supplement Irish populations.
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Phylogeography of willow grouse (lagopus lagopus) in the Arctic: taxonomic discordance as inferred from molecular data
Biological Journal of the Linnean Society, 2013Co-Authors: Jacob Höglund, Biao Wang, Thomas Axelsson, María QuintelaAbstract:Using independently segregating nuclear single nucleotide polymorphisms (SNPs) and mitochondrial control region sequences, we found an east-west division among sampled willow grouse lagopus lagopus subspecies. This division cut across the range of the subspecies with the largest distribution (lagopus) and thus contradicted existing taxonomic classifications. Russian lagopus lagopus lagopus tended to cluster with North American willow grouse partly classified as other subspecies. Scandinavian willow grouse (L. l. lagopus) clustered with red grouse from Britain and Ireland (lagopus lagopus scoticus and lagopus lagopus hibernicus) but substructuring confirmed the monophyly of the latter. In North America, we could not detect any major genetic divisions apart from two birds described as alexandrae from the Heceta Island (Alaska) when using mitochondrial sequences. Other samples from North America were intermingled regardless of whether they were described as muriei, alexandrae or lagopus .A specimen described as alexandrae was to some extent distinct when analysing the SNP data. The genetic analyses indicated some concordance between genetics and taxonomy but not complete congruence. This is particularly evident for mitochondrial DNA network analyses. We suggest that the taxonomy of this species would benefit by a careful re-examination of the available evidence for subspecies. It appears as if subspecies status is a poor proxy for assigning evolutionary significant units and management units in this species. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 110, 77-90. ADDITIONAL KEYWORDS: alexandrae - evolutionary significant unit - hibernicus - kamschatkensis - lagopus lagopus - muriei - phylogeography - scoticus - willow grouse subspecies.
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Genetic variation among endangered Irish red grouse (lagopus lagopus hibernicus) populations: implications for conservation and management
Conservation Genetics, 2012Co-Authors: Barry J. Mcmahon, Stuart B. Piertney, Kieran Buckley, Magnus P. Johansson, Jacob HöglundAbstract:Extant populations of Irish red grouse ( lagopus lagopus hibernicus ) are both small and fragmented, and as such may have an increased risk of extinction through the effects of inbreeding depression and compromised adaptive potential. Here we used 19 microsatellite markers to assay genetic diversity across 89 georeferenced samples from putatively semi-isolated areas throughout the Republic of Ireland and we also genotyped 27 red grouse from Scotland using the same markers. The genetic variation within Ireland was low in comparison to previously published data from Britain and the sample of Scottish red grouse, and comparable to threatened European grouse populations of related species. Irish and Scottish grouse were significantly genetically differentiated (F_ST = 0.07, 95% CI = 0.04–0.10). There was evidence for weak population structure within Ireland with indications of four distinct genetic clusters. These correspond approximately to grouse populations inhabiting suitable habitat patches in the North West, Wicklow Mountains, Munster and Cork, respectively, although some admixture was detected. Pair-wise F_ST values among these populations ranged from 0.02 to 0.04 and the overall mean allelic richness was 5.5. Effective population size in the Munster area was estimated to be 62 individuals (95% CI = 33.6–248.8). Wicklow was the most variable population with an AR value of 5.4 alleles/locus. Local (Munster) neighbourhood size was estimated to 31 individuals corresponding to an average dispersal distance of 31 km. In order to manage and preserve Irish grouse we recommend that further fragmentation and destruction of habitats need to be prevented in conjunction with population management, including protection of the integrity of the existing population by refraining from augmenting it with individuals from mainland Britain to maximise population size.
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Genetic diversity and differentiation among lagopus lagopus populations in Scandinavia and Scotland: evolutionary significant units confirmed by SNP markers
Molecular ecology, 2010Co-Authors: María Quintela, Biao Wang, Sofia Berlin, Jacob HöglundAbstract:Single Nucleotide Polymorphism in four Scandinavian populations of willow grouse (lagopus lagopus) and two Scottish populations of red grouse (lagopus lagopus scoticus) were assessed at 13 protein-coding loci. We found high levels of diversity, with one substitution every 55 bp as an average and a total of 76 unlinked parsimony informative SNPs. Different estimators of genetic diversity such as: number of synonymous and non-synonymous sites, average number of alleles, number and percentage of polymorphic loci, mean nucleotide diversity (pi(s), pi(a)) and gene diversity at synonymous and non-synonymous sites showed higher diversity in the northern populations compared to southern ones. Strong levels of purifying selection found in all the populations together with neutrality tests conforming to neutral expectations agree with large effective population sizes. Assignment tests reported a clear distinction between Scandinavian and Scottish grouse suggesting the existence of two different evolutionary significant units. The divergence time between willow and red grouse ranging between 12 500 and 125 000 years, in conjunction with the presence of 'specific' markers for each subspecies prompt a reassessment of the taxonomical status of the Scottish red grouse.
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Sequence polymorphism in candidate genes for differences in winter plumage between Scottish and Scandinavian Willow Grouse (lagopus lagopus).
PloS one, 2010Co-Authors: Pontus Skoglund, Jacob HöglundAbstract:BACKGROUND Population variation in the degree of seasonal polymorphism is rare in birds, and the genetic basis of this phenomenon remains largely undescribed. Both sexes of Scandinavian and Scottish Willow grouse (lagopus lagopus) display marked differences in their winter phenotypes, with Scottish grouse retaining a pigmented plumage year-round and Scandinavian Willow grouse molting to a white morph during winter. A widely studied pathway implicated in vertebrate pigmentation is the melanin system, for which functional variation has been characterised in many taxa. METHODOLOGY/PRINCIPAL FINDINGS We sequenced coding regions from four genes involved in melanin pigmentation (DCT, MC1R, TYR and TYRP1), and an additional control involved in the melanocortin pathway (AGRP), to investigate the genetic basis of winter plumage in lagopus. Despite the well documented role of the melanin system in animal coloration, we found no plumage-associated polymorphism or evidence for selection in a total of approximately 2.6 kb analysed sequence. CONCLUSIONS/SIGNIFICANCE Our results indicate that the genetic basis of alternating between pigmented and unpigmented seasonal phenotypes is more likely explained by regulatory changes controlling the expression of these or other loci in the physiological pathway leading to pigmentation.
Peter J Hudson - One of the best experts on this subject based on the ideXlab platform.
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faecal egg counts provide a reliable measure of trichostrongylus tenuis intensities in free living red grouse lagopus lagopus scoticus
Journal of Helminthology, 2004Co-Authors: Linzi Seivwright, Stephen M Redpath, Francois Mougeot, L Watt, Peter J HudsonAbstract:The reliability of different egg counting methods for estimating the intensity of Trichostrongylus tenuis infections in red grouse, lagopus lagopus scoticus, was investigated in the autumn, when grouse may harbour high parasite intensities. Possible limitations to the use of these methods were also examined. Faecal egg counts were found to accurately estimate T. tenuis worm intensities, at least up to an observed maximum of c. 8000 worms. Two egg counting methods (smear and McMaster) gave consistent results, although the exact relationship with worm intensity differed according to the method used. Faecal egg counts significantly decreased with increasing length of sample storage time, but egg counts were reliable for estimating worm intensity for three weeks. The concentration of eggs in the caecum was also found to reliably estimate worm intensity. However, egg counts from frozen gut samples cannot be used to estimate worm intensities. These results conclude that, despite some limitations, faecal and caecum egg counts provide useful and reliable ways of measuring T. tenuis intensities in red grouse.
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Rising burden of immature sheep ticks (Ixodes ricinus) on red grouse (lagopus lagopus scoticus) chicks in the Scottish uplands.
Medical and Veterinary Entomology, 2004Co-Authors: A. D. Kirby, A. A. Smith, Tim G. Benton, Peter J HudsonAbstract:The sheep tick Ixodes ricinus (L.) (Acari: Ixodidae) is an ectoparasite of major economic and pathogenic importance in Scotland. Its distribution in the Scottish uplands is assumed to be governed by the abundance and distribution of its definitive hosts (deer and sheep) and climatic variables such as temperature and rainfall. As the numbers of its major host in Scotland, red deer, have increased dramatically and climatic conditions have become more favourable, the level of parasitism could have been expected to rise. We use data gathered from tick counts on over 4000 red grouse chicks lagopus lagopus scoticus Latham (Galliformes: Tetraonidae) in various experiments over the past 19 years to ascertain whether the intensity and prevalence of parasitism has been increasing. From 1985 to 2003 the average tick burden of a parasitized red grouse chick has grown from 2.60 � 1.12 ticks per chick to 12.71 � 1.44. Over this period the percentage of chicks of a given brood parasitized has also increased from 4 � 2% to 92 � 3%. The possible implications of this increase in parasitism for red grouse production are discussed.
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territorial status and survival in red grouse lagopus lagopus scoticus hope for the doomed surplus
Journal of Avian Biology, 2002Co-Authors: Kirsty J. Park, Martha Maud Hurley, Peter J HudsonAbstract:A previous study of survival in territorial and non-territorial red grouse lagopus lagopus scoticus conducted between 1957 and 1967 found that territorial status in the autumn pre-determined over-winter survival. A very high proportion of territorial birds survived and virtually all non-territorial birds died or emigrated. We tested the hypothesis that over-winter survival was dependent on territorial status within four grouse populations in Scotland between 1986 and 1993. In contrast to the previous study, 66% of non-territorial birds survived over winter compared to approximately 70% of territorial birds. There was no significant effect of territorial status on the survival estimates. Moreover, some of the birds considered to be non-territorial during autumn went on to successfully raise a brood. We suggest that on our study sites, territory ownership in autumn did not greatly influence over-winter survival, and territorial behaviour did not determine breeding density as previously supposed. We postulate differences with other studies may reflect variations in scale and predation pressure.
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Harvesting unstable populations: red grouse lagopus lagopus scoticus (Lath.) in the United Kingdom
Wildlife Biology, 2001Co-Authors: Peter J Hudson, Andrew P DobsonAbstract:The optimal harvesting strategies for unstable populations are explored using first discrete time models and second a continuous time model specifically applied to the destabilising effects of the caecal nematode Trichostrongylus tenuis on the dynamics of red grouse lagopus lagopus scoticus. In discrete time models, with overcompensation generating either cyclic or chaotic fluctuations in abundance harvesting can act as both a stabilising and a destabilising process. Maximum yields occur at the harvesting rate that coincides with the point where the harvesting stabilises the overcompensation. Optimal harvesting rates increase with the degree of overcompensation although these are more vulnerable to overharvesting. Harvesting in the continuous time model provides similar results, although observed hunting records do not appear to be stabilised by harvesting. Empirical data on the mortality caused by other natural enemies of red grouse, the hen harrier Circus cyaenus and the louping ill virus, show that the...
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The role of invertebrates in the diet, growth and survival of red grouse (lagopus lagopus scoticus) chicks
Journal of Zoology, 2001Co-Authors: Kirsty J. Park, David Newborn, Steven T Campbell, Peter A. Robertson, Robin Foster, Zoe M Russell, Peter J HudsonAbstract:The role of diet on the growth, survival and movement of red grouse lagopus lagopus scoticus chicks was examined. We compared two areas of moorland in Scotland: a dry heath with a low density of red grouse and poor chick survival; and a wetter heath/bog with relatively higher red grouse numbers and higher rates of chick survival. There were no differences in clutch size or the proportion of eggs hatching between the two moors but brood survival was significantly lower on the dry heath. Radio-tagged hens with broods were monitored during the first 12 days following hatching; the chicks were captured, weighed and faecal samples collected. Invertebrate samples were collected within brood feeding ranges. Analysis of chick faeces was used to identify dietary components. Heather comprised the major dietary component on both moors. Invertebrates formed a higher component of diet on the wet moor, and this was positively correlated with growth rates, which in turn were positively correlated with chick survival. We present data from an experiment carried out in 1982, in which chicks showed higher growth rates with increasing insect availability. We also show that broods in which all the chicks survived (4 ‐10 days) had smaller home-range areas than broods in which some of the chicks died during this period. We suggest that the differences in chick survival between the two populations were the result of variations in the abundance of invertebrates, particularly tipulids. The protein provided by a high invertebrate component in the diet is, therefore, an important determinant of the growth and survival of young red grouse chicks in some areas.
Francois Mougeot - One of the best experts on this subject based on the ideXlab platform.
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carotenoid profile and vitamins in the combs of the red grouse lagopus lagopus scoticus implications for the honesty of a sexual signal
Journal of Ornithology, 2016Co-Authors: Lorenzo Perezrodriguez, Francois Mougeot, Garcia E De Blas, Jesus Martinezpadilla, Rafael MateoAbstract:The carotenoid-based ornaments displayed by many birds often play key roles in social and sexual signalling, revealing information about individual quality. However, the proximate regulation of the honesty of sexual traits remains controversial. Understanding the mechanisms of coloured trait production and maintenance requires an accurate description of their chemical composition and of the physiological pathways involved in pigment production and deposition in the ornaments. Carotenoid-based colouration has been extensively studied in birds, but such information is often lacking for coloured integuments other than feathers, such as fleshy carotenoid-based ornaments. Here we report the carotenoid composition of the combs of the red grouse (lagopus lagopus scoticus), a sexual trait that honestly reveals individual quality. In the present study, we also investigated blood carotenoid content, as well as associations between carotenoids, retinol and tocopherol (the active forms of vitamin A and E, respectively) within the ornament. We found that comb pigmentation was primarily the result of two red ketocarotenoids (astaxanthin and papilioerythrinone), which are synthesised from their dietary precursors (zeaxanthin and lutein) directly at the comb integument. These red ketocarotenoids are largely deposited esterified with fatty acids. Astaxanthin concentration in the comb was found to negatively correlate with retinol levels but positively correlate with tocopherol levels. Considering evidence from this and other studied species, we suggest that carotenoid esterification is a characteristic of coloured fleshy integuments, probably affecting pigment stability and colouration in living tissues, with subsequent effects on their signalling role and maintenance costs. We found little evidence that the honesty of this signal would result from a direct connection with vitamin A metabolism, as recently proposed. Rather, honest signalling via comb colouration appears more related to potential allocation trade-offs of some specific dietary precursors or to the capacity of individuals to manage the redox reactions interfering with carotenoid metabolism.
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Insights into population ecology from long-term studies of red grouse lagopus lagopus scoticus.
Journal of Animal Ecology, 2013Co-Authors: Jesús Martínez-padilla, Stephen M Redpath, Mohammed Zeineddine, Francois MougeotAbstract:Summary Long-term studies have been the backbone of population ecology. The red grouse lagopus lagopus scoticus is one species that has contributed widely to this field since the 1950s. This paper reviews the trajectory and profound impact that these studies have had. Red grouse research has combined long-term studies of marked individuals with demographic studies over wide geographical areas and replicated individual- and population-level manipulations. A main focus has been on understanding the causes of population cycles in red grouse, and in particular the relative importance of intrinsic (behaviour) and extrinsic (climate, food limitation and parasite) mechanisms. Separate studies conducted in different regions initially proposed either the nematode parasite Trichostrongylus tenuis or changes in male aggressiveness in autumn as drivers of population cycles. More recent experiments suggest that parasites are not a necessary cause for cycles and have highlighted that behavioural and parasite-mediated mechanisms are interrelated. Long-term experiments show that parasites and aggressiveness interact. Two outstanding questions remain to be tested experimentally. First, what intrinsic mechanism causes temporal variation in patterns of male aggressiveness? The current favoured mechanism is related to patterns of kin structuring although there are alternative hypotheses. Second, how do the dual, interacting mechanisms, affect population dynamics? Red grouse studies have had an important impact on the field of population ecology, in particular through highlighting: (1) the impact of parasites on populations; (2) the role of intrinsic mechanisms in cyclic dynamics and (3) the need to consider multiple, interacting mechanisms.
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Temporal changes in kin structure through a population cycle in a territorial bird, the red grouse lagopus lagopus scoticus
Molecular Ecology, 2008Co-Authors: Stuart B. Piertney, F Leckie, Francois Mougeot, Andrew D. C. Maccoll, Xavier Lambin, John F. Dallas, Philip J. Bacon, Paul A Racey, Kerry Lock, Stephen M RedpathAbstract:Populations of red grouse (lagopus lagopus scoticus) undergo regular multiannual cycles in abundance. The ‘kinship hypothesis’ posits that such cycles are caused by changes in kin structure among territorial males producing delayed density-dependent changes in aggressiveness, which in turn influence recruitment and regulate density. The kinship hypothesis makes several specific predictions about the levels of kinship, aggressiveness and recruitment through a population cycle: (i) kin structure will build up during the increase phase of a cycle, but break down prior to peak density; (ii) kin structure influences aggressiveness, such that there will be a negative relationship between kinship and aggressiveness over the years; (iii) as aggressiveness regulates recruitment and density, there will be a negative relationship between aggressiveness in one year and both recruitment and density in the next; (iv) as kin structure influences recruitment via an affect on aggressiveness, there will be a positive relationship between kinship in one year and recruitment the next. Here we test these predictions through the course of an 8-year cycle in a natural population of red grouse in northeast Scotland, using microsatellite DNA markers to resolve changing patterns of kin structure, and supra-orbital comb height of grouse as an index of aggressiveness. Both kin structure and aggressiveness were dynamic through the course of the cycle, and changing patterns were entirely consistent with the expectations of the kinship hypothesis. Results are discussed in relation to potential drivers of population regulation and implications of dynamic kin structure for population genetics.
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Ornamental comb colour predicts T-cell-mediated immunity in male red grouse lagopus lagopus scoticus.
Naturwissenschaften, 2007Co-Authors: Francois MougeotAbstract:Sexual ornaments might reliably indicate the ability to cope with parasites and diseases, and a better ability to mount a primary inflammatory response to a novel challenge. Carotenoid-based ornaments are amongst the commonest sexual signals of birds and often influence mate choice. Because carotenoids are immuno-stimulants, signallers may trade-off allocating these to ornamental colouration or using them for immune responses, so carotenoid-based ornaments might be particularly useful as honest indicators of immuno-compentence. Tetraonid birds, such as the red grouse lagopus lagopus scoticus, exhibit supra-orbital yellow–red combs, a conspicuous ornament which functions in intra- and inter-sexual selection. The colour of combs is due to epidermal pigmentation by carotenoids, while their size is testosterone-dependent. In this study, I investigated whether comb characteristics, and in particular, comb colour, indicated immuno-competence in free-living male red grouse. I assessed T-cell-mediated immunity using a standardised challenge with phytohaemagglutinin. Red grouse combs reflect in the red and in the ultraviolet spectrum of light, which is not visible to humans but that grouse most likely see, so I measured comb colour across the whole bird visible spectrum (300–700 nm) using a reflectance spectrometer. I found that males with bigger and redder combs, but with less ultraviolet reflectance, had greater T-cell-mediated immune response. Comb colour predicted T-cell-mediated immune response better than comb size, indicating that the carotenoid-based colouration of this ornament might reliably signal this aspect of male quality.
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Alternative methods for estimating density in an upland game bird: the red grouse lagopus lagopus scoticus
Wildlife Biology, 2007Co-Authors: Sharon A. Evans, F Leckie, Stephen M Redpath, Francois MougeotAbstract:Abstract For some species, reliable quantitative estimates of population size can be difficult to obtain. Density estimates of red grouse lagopus lagopus scoticus are usually obtained through counts using trained pointer dogs. In this paper, we examine two alternative, and potentially easier, methods for estimating red grouse breeding density: one direct, based on counts of males responding to playbacks of territorial calls, and one indirect, based on counts of droppings along transects. We counted grouse on 14 1-km2 areas for 1-3 years in 2002-2004 using trained dogs and compared these density estimates (range: 23-220 grouse/km2) with density estimates derived from playback counts and dropping counts. For playback counts, we counted males responding to a playback of territorial calls at nine points spread over a given 1-km2 area. For dropping counts, we counted the number of fibrous dropping roost piles along two 1-km transects across each 1-km2 area. Generalised Linear Models indicated that male, female...
