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Youngmi Lee - One of the best experts on this subject based on the ideXlab platform.
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Oxidative stress responses in brackish Water Flea exposed to microcystin-LR and algal bloom Waters from Nakdong River, Republic of Korea.
Marine pollution bulletin, 2020Co-Authors: Eun-ji Won, Dokyun Kim, Je-won Yoo, Kyung-hoon Shin, Youngmi LeeAbstract:Abstract Microcystis blooms and the impact of their toxins, particularly microcystin (MC), in coastal ecosystems is an emerging threat, but the species-specific effects of MC and the potential for bioconcentration are not fully understood. We exposed the brackish Water Flea, Diaphanosoma celebensis, to MC-LR, which showed antioxidant responses measured at the molecular to enzyme levels but no acute toxicity. We extended our experimental investigation to measure the released MC and its uptake by D. celebensis exposed to river Water. In a short-term exposure (48 h) experiment, D. celebensis exposed to Water from an algal bloom (approximately 2 μg L−1 MC) assimilated more than 50 pg MC per individual. The significant increase of MCs suggests the potential for the species to accumulate MCs. The dose-dependent increase in the antioxidant response observed in the mRNA levels also showed that D. celebensis exposed to diluted algal bloom Waters were affected by toxins from cyanobacteria.
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Effects of heavy metals on the expression of digestive enzyme-coding genes in the brackish Water Flea Diaphanosoma celebensis
Toxicology and Environmental Health Sciences, 2020Co-Authors: Jiyoon Lee, Youngmi LeeAbstract:Objectives Energy metabolism is an essential physiological event for all life forms, and, in heterotrophic organisms, it significantly depends on food intake. Digestive enzymes play an important role in acquiring the nutrients required for metabolic pathways. Thus, the aim of this study was to investigate the transcriptional modulation of digestive enzyme-coding genes in response to heavy metals in the brackish Water Flea Diaphanosoma celebensis . Methods Sublethal concentrations of inorganic arsenic (As), cadmium (Cd), and lead (Pb) on the brackish Water Flea D. celebensis were calculated from the 48 h acute toxicity test result. The relative mRNA expression levels of six digestive enzyme-coding genes ( AMY and AMY - like for carbohydrates; TRYP and CHY for proteins; LIP and PLRP for lipids) after 48 h of exposure to heavy metals were evaluated by real-time reverse transcription-polymerase chain reaction. Results A significant increase in the mRNA expression of AMY, AMY - like, TRYP , and PLRP was observed in all concentration of As (1.17–3.94 fold-change, p
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Effects of heavy metals on the expression of digestive enzyme-coding genes in the brackish Water Flea Diaphanosoma celebensis
Toxicology and Environmental Health Sciences, 2020Co-Authors: Jiyoon Lee, Youngmi LeeAbstract:Energy metabolism is an essential physiological event for all life forms, and, in heterotrophic organisms, it significantly depends on food intake. Digestive enzymes play an important role in acquiring the nutrients required for metabolic pathways. Thus, the aim of this study was to investigate the transcriptional modulation of digestive enzyme-coding genes in response to heavy metals in the brackish Water Flea Diaphanosoma celebensis. Sublethal concentrations of inorganic arsenic (As), cadmium (Cd), and lead (Pb) on the brackish Water Flea D. celebensis were calculated from the 48 h acute toxicity test result. The relative mRNA expression levels of six digestive enzyme-coding genes (AMY and AMY-like for carbohydrates; TRYP and CHY for proteins; LIP and PLRP for lipids) after 48 h of exposure to heavy metals were evaluated by real-time reverse transcription-polymerase chain reaction. A significant increase in the mRNA expression of AMY, AMY-like, TRYP, and PLRP was observed in all concentration of As (1.17–3.94 fold-change, p Pb > As. The increase in digestive enzyme-coding genes in response to As and a lower concentration of Pb may be closely associated with protective effects to compensate for changing food availability. Cd and the higher concentration of Pb could disrupt energy metabolism by downregulating the digestive enzyme-coding genes.
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Modulation of glutathione S -transferase and superoxide dismutase in response to heavy metals in brackish Water Flea Diaphanosoma celebensis
Toxicology and Environmental Health Sciences, 2020Co-Authors: Je-won Yoo, Hayoung Cho, Youngmi LeeAbstract:Superoxide dismutase (SOD) and glutathione S-transferase (GST) serve as biomarkers of oxidative stress in aquatic organisms. However, the modulatory effects of heavy metals on the expression of small crustaceans are yet unknown. The acute toxicity of inorganic arsenic (As), cadmium (Cd), and lead (Pb) to the brackish Water Flea Diaphanosoma celebensis (4 days old) was evaluated to determine their sublethal concentrations. Modulations in the activities and transcription of SODs (Cu/Zn-SOD and Mn-SOD) and GSTs (mu, kappa, theta, and sigma) in response to sublethal concentrations of heavy metals were investigated for 48 h. The 48-h median lethal concentration (LC50) was determined to be 2.62 mg/L, 2.60 mg/L, and 0.37 mg/L for Cd, As, and Pb, respectively, and the order of toxicity in this species was Pb > Cd = As. SOD and GST activities were induced after exposure to all metals; in particular, GST activity was sensitively enhanced upon As exposure. Real-time reverse-transcriptase polymerase chain reaction showed that GST mu and GST sigma were specific for As, and GST kappa and GST theta for Cd. Mn-SOD mRNA expression was more sensitive to As. These findings suggest that D. celebensis SOD and GST may be involved in the antioxidant defense mechanisms to heavy metals. These genes may serve as useful biomarkers for risk assessment of heavy metal pollution in aquatic ecosystems. This study may be helpful for the better understanding of the molecular mode of action of heavy metals in small crustaceans and provide preliminary data for future studies evaluating the combined effects of heavy metal mixture.
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Cloning and molecular characterization of estrogen-related receptor (ERR) and vitellogenin genes in the brackish Water Flea Diaphanosoma celebensis exposed to bisphenol A and its structural analogues
Marine Pollution Bulletin, 2020Co-Authors: Hayoung Cho, Eun-ji Won, Kyun-woo Lee, Youngmi LeeAbstract:Abstract Although it has previously been shown that bisphenol (BP) analogues may interfere with the normal hormonal regulation by acting as endocrine disrupting chemicals (EDCs), little information is available on effects of BP analogues in invertebrates, particularly on cladocerans. In the present study, we identified estrogen-related receptors (EER), vitellogenin (VTG), and VTG receptor (VtgR) from the brackish Water Flea Diaphanosoma celebensis, and examined the effects of BPA and the substitutes, BPF and BPS, in different sublethal concentrations. Gene expression varied with time well matched with brooding, suggesting that DcEER, DcVTG, and DcVtgR play a role in reproduction in D. celebensis. qRT-PCR analysis showed that BPA and its substitutes differently modulated mRNA expressions of DcEER, DcVTG, and DcVtgR, indicating that these compounds adversely affect the normal reproduction-related pathway. This study facilitates better understanding of the molecular mode of action of BP analogues on the reproductive system of D. celebensis.
L. De Meester - One of the best experts on this subject based on the ideXlab platform.
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corrigendum rapid evolution of thermal tolerance in the Water Flea daphnia
Nature Climate Change, 2015Co-Authors: Aurora N. Geerts, Bram Vanschoenwinkel, Joost Vanoverbeke, W. Van Doorslaer, Heidrun Feuchtmayr, David Atkinson, Brian Moss, Thomas A. Davidson, Carl D. Sayer, L. De MeesterAbstract:Nature Clim. Change 5, 665–668 (2015); published online 27 April 2015; corrected after print 3 September 2015 In the version of this Letter originally published, in Fig. 1a, the boxplot for the Ambient +4 °C treatment was incorrect. This error has been corrected in the online versions.
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Rapid evolution of thermal tolerance in the Water Flea Daphnia
Nature Climate Change, 2015Co-Authors: Aurora N. Geerts, Bram Vanschoenwinkel, Joost Vanoverbeke, W. Van Doorslaer, Heidrun Feuchtmayr, David Atkinson, Brian Moss, Thomas A. Davidson, Carl D. Sayer, L. De MeesterAbstract:A manipulation experiment, combined with reconstructed evolutionary history from a dormant egg bank found in recent lake sediments, reveals that Water Fleas (Daphnia) can exhibit a rapid increase in their capacity to tolerate higher temperatures.
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Coping with predator stress: interclonal differences in induction of heat-shock proteins in the Water Flea Daphnia magna.
Journal of evolutionary biology, 2005Co-Authors: Kevin Pauwels, Robby Stoks, L. De MeesterAbstract:Although predation is a strong selection pressure, little is known about the molecular mechanisms to cope with predator stress. This is crucial to understanding of the mechanisms and constraints involved in the evolution of antipredator traits. We quantified the expression of heat-shock protein 60 (Hsp60), a potential marker for predator stress, in four clones of the Water Flea Daphnia magna, when exposed to fish kairomones. Expression of Hsp60 induction increased after 6 h and returned to base levels after 24 h of predator stress. This suggests that it is a costly transient mechanism to temporarily cope with novel predator stress, before other defences are induced. We found genetic variation in the fixed levels and in the fish-induced levels of Hsp60, which seemed to be linked to each clone's history of fish predation. Our data suggest that Hsp60 can be considered part of a multiple-trait antipredator defence strategy of Daphnia clones to cope with predator stress.
Aurora N. Geerts - One of the best experts on this subject based on the ideXlab platform.
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The power of numbers: dynamics of hatching and dormant egg production in two populations of the Water Flea Daphnia magna
Aquatic Ecology, 2019Co-Authors: Aurora N. Geerts, Luc Brendonck, Kelle Moreau, Bram Vanschoenwinkel, Joost Vanoverbeke, Luc De MeesterAbstract:Many organisms that live in inland standing Waters produce dormant life stages that can accumulate in propagule banks to survive temporarily unfavourable periods. These egg banks have important effects on the ecology of populations and communities in terms of phenology, population densities, the probability of extinction, species diversity and habitat connectivity in time and space. They also have important consequences for the evolutionary versatility of populations. Although diapause and dormant egg banks in freshWater zooplankton have been studied for several decades, little is known about the quantitative contribution of egg production and hatching to yearly egg bank budgets and their seasonality in natural ponds and lakes. Here we quantified inter- and intra-annual variation in hatching and dormant egg production in the Water Flea Daphnia magna in two natural shallow ponds in Flanders (Belgium) using high-intensity sampling and in situ measurements. Hatching started in spring and occurred in several bouts (April–July), accumulating to a yearly average total of 3.5 × 103 hatchlings m−2. Dormant egg production occurred in one-to-three bouts mainly during late spring and summer (May–August), resulting in a total yearly production ranging from 1.2 × 104 up to 17.3 × 104 ephippia m−2. In both years, there was an average surplus of 3.14 × 104 and 15.24 × 104 ephippia produced m−2 for ponds OM2 and OM3, respectively, contributing to the accumulation of the persistent egg bank. We discuss the ecological and evolutionary consequences of both the high number of ephippia that are produced and the high number of hatchlings at the start of each growing season.
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corrigendum rapid evolution of thermal tolerance in the Water Flea daphnia
Nature Climate Change, 2015Co-Authors: Aurora N. Geerts, Bram Vanschoenwinkel, Joost Vanoverbeke, W. Van Doorslaer, Heidrun Feuchtmayr, David Atkinson, Brian Moss, Thomas A. Davidson, Carl D. Sayer, L. De MeesterAbstract:Nature Clim. Change 5, 665–668 (2015); published online 27 April 2015; corrected after print 3 September 2015 In the version of this Letter originally published, in Fig. 1a, the boxplot for the Ambient +4 °C treatment was incorrect. This error has been corrected in the online versions.
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Rapid evolution of thermal tolerance in the Water Flea Daphnia
Nature Climate Change, 2015Co-Authors: Aurora N. Geerts, Bram Vanschoenwinkel, Joost Vanoverbeke, W. Van Doorslaer, Heidrun Feuchtmayr, David Atkinson, Brian Moss, Thomas A. Davidson, Carl D. Sayer, L. De MeesterAbstract:A manipulation experiment, combined with reconstructed evolutionary history from a dormant egg bank found in recent lake sediments, reveals that Water Fleas (Daphnia) can exhibit a rapid increase in their capacity to tolerate higher temperatures.
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Thermal Genetic Adaptation in the Water Flea Daphnia and its Impact: An Evolving Metacommunity Approach
Integrative and comparative biology, 2011Co-Authors: Luc De Meester, Aurora N. Geerts, W. Van Doorslaer, Luisa Orsini, Robby StoksAbstract:Genetic adaptation to temperature change can impact responses of populations and communities to global warming. Here we integrate previously published results on experimental evolution trials with follow-up experiments involving the Water Flea Daphnia as a model system. Our research shows (1) the capacity of natural populations of this species to genetically adapt to changes in temperature in a time span of months to years, (2) the context-dependence of these genetic changes, emphasizing the role of ecology and community composition on evolutionary responses to climatic change, and (3) the impact of micro-evolutionary changes on immigration success of preadapted genotypes. Our study involves (1) experimental evolution trials in the absence and presence of the community of competitors, predators, and parasites, (2) life-table and competition experiments to assess the fitness consequences of micro-evolution, and (3) competition experiments with putative immigrant genotypes. We use these observations as building blocks of an evolving metacommunity to understand biological responses to climatic change. This approach integrates both local and regional responses at both the population and community levels. Finally, we provide an outline of current gaps in knowledge and suggest fruitful avenues for future research.
Hajime Watanabe - One of the best experts on this subject based on the ideXlab platform.
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Complete mitochondrial genome of the freshWater Water Flea Daphnia magna NIES strain (Cladocera, Daphniidae): Rearrangement of two ribosomal RNA genes
Mitochondrial DNA Part B, 2020Co-Authors: Jin-sol Lee, Beom-soon Choi, Duck-hyun Kim, Yasuhiko Kato, Hajime Watanabe, Jae-seong LeeAbstract:The complete mitochondrial genome was sequenced from the NIES strain of the freshWater Water Flea Daphnia magna. The sequenced mitochondrial genome size of the NIES strain of D. magna was 17,432 bp...
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Early embryonic expression of a putative ecdysteroid-phosphate phosphatase in the Water Flea, Daphnia magna (Cladocera: Daphniidae).
Journal of insect science (Online), 2014Co-Authors: Miki Asada, Yasuhiko Kato, Tomoaki Matsuura, Hajime WatanabeAbstract:Ecdysteroids, known as molting hormones, play central roles in the onset of molting, metamorphosis, and reproduction in arthropods. The ecdysteroids stored in eggs also play an important role in embryogenesis. In insects, ecdysteroids are stored as phosphate esters, which are converted to an active form by ecdysteroid-phosphate phosphatase (EPPase). Although EPPase is believed to be widely conserved in the Ecdysozoa, little is known about its expression in clades other than Insecta. In this study, we cloned a putative EPPase gene from a small fresh Water crustacean known as a Water Flea, Daphnia magna Straus (Cladocera: Daphniidae), and examined its expression during embryogenesis. The amino acid sequence of the putative crustacean EPPase cDNA showed high similarity to insect EPPase and human suppressor of T-cell receptor signaling-1. We also found that the D. magna EPPase was highly expressed during early embryogenesis; its expression rapidly decreased 6 h after oviposition. This timing corresponds to the onset of organogenesis in D. magna. The expression of EPPase could not be detected in diapaused eggs. This is the first report of an EPPase from crustaceans, and the results suggest that the function of EPPase is conserved between insects and crustaceans.
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molecular cloning of doublesex genes of four cladocera Water Flea species
BMC Genomics, 2013Co-Authors: Kenji Toyota, Hitoshi Miyakawa, Yasuhiko Kato, Hajime Watanabe, Masaru Sato, Naomi Sugiura, Shinichi MiyagawaAbstract:The gene doublesex (dsx) is known as a key factor regulating genetic sex determination in many organisms. We previously identified two dsx genes (DapmaDsx1 and DapmaDsx2) from a freshWater branchiopod crustacean, Daphnia magna, which are expressed in males but not in females. D. magna produces males by parthenogenesis in response to environmental cues (environmental sex determination) and we showed that DapmaDsx1 expression during embryonic stages is responsible for the male trait development. The D. magna dsx genes are thought to have arisen by a cladoceran-specific duplication; therefore, to investigate evolutionary conservation of sex specific expression of dsx genes and to further assess their functions in the environmental sex determination, we searched for dsx homologs in four closely related cladoceran species. We identified homologs of both dsx genes from, D. pulex, D. galeata, and Ceriodaphnia dubia, yet only a single dsx gene was found from Moina macrocopa. The deduced amino acid sequences of all 9 dsx homologs contained the DM and oligomerization domains, which are characteristic for all arthropod DSX family members. Molecular phylogenetic analysis suggested that the dsx gene duplication likely occurred prior to the divergence of these cladoceran species, because that of the giant tiger prawn Penaeus monodon is rooted ancestrally to both DSX1 and DSX2 of cladocerans. Therefore, this result also suggested that M. macrocopa lost dsx2 gene secondarily. Furthermore, all dsx genes identified in this study showed male-biased expression levels, yet only half of the putative 5’ upstream regulatory elements are preserved in D. magna and D. pulex. The all dsx genes of five cladoceran species examined had similar amino acid structure containing highly conserved DM and oligomerization domains, and exhibited sexually dimorphic expression patterns, suggesting that these genes may have similar functions for environmental sex determination in cladocerans.
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cloning and characterization of the ecdysone receptor and ultraspiracle protein from the Water Flea daphnia magna
Journal of Endocrinology, 2007Co-Authors: Yasuhiko Kato, Norihisa Tatarazako, Hajime Watanabe, Shigeto Oda, Kaoru Kobayashi, Taisen IguchiAbstract:cDNAsencodingtheecdysonereceptor(EcR)andultraspiracle (USP) protein were cloned from the Water Flea Daphnia magna (Crustacea:Cladocera).ThededucedEcRandUSPaminoacid sequences showed a high degree of homology to those of other crustaceans aswell as insects. We isolated three isoforms of EcR that differ in the A/B domain. Quantitative PCR analysis indicated differing temporal expression patterns of the EcR isoforms during the molting period and demonstrated that the expression of one subtype correlated well with the timing of molt. Using cDNAs encoding EcR and USP, we constructed a Daphnia EcR/USP reporter based on a two-hybrid system. The gene fusions encoded the EcR ligand-binding domain (LBD) fused to the Gal4 DNA-binding domain, and the USP‐LBD fused to the Vp16 activation domain. These chimeric genes were transfected with a luciferase reporter gene. Dose-dependent activation of the reporter gene could be observed when transfectants were exposed to Ec and other chemicals known to have Ec-like activities. This two-hybrid system may represent a useful reporter system for further examination of hormonal and chemical effects on Daphnia at the molecular level.
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Analysis of expressed sequence tags of the Water Flea Daphnia magna
Genome, 2005Co-Authors: Hajime Watanabe, Norihisa Tatarazako, Shigeto Oda, Hiroyo Nishide, Ikuo Uchiyama, Masatoshi Morita, Taisen IguchiAbstract:To study gene expression in the Water Flea Daphnia magna we constructed a cDNA library and characterized the expressed sequence tags (ESTs) of 7210 clones. The EST sequences clustered into 2958 nonredundant groups. BLAST analyses of both protein and DNA databases showed that 1218 (41%) of the unique sequences shared significant similarities to known nucleotide or amino acid sequences, whereas the remaining 1740 (59%) showed no significant similarities to other genes. Clustering analysis revealed particularly high expression of genes related to ATP synthesis, structural proteins, and proteases. The cDNA clones and EST sequence information should be useful for future functional analysis of daphnid biology and investigation of the links between ecology and genomics.Key words: Daphnia magna, EST, classification, ATP synthesis.
W. Van Doorslaer - One of the best experts on this subject based on the ideXlab platform.
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corrigendum rapid evolution of thermal tolerance in the Water Flea daphnia
Nature Climate Change, 2015Co-Authors: Aurora N. Geerts, Bram Vanschoenwinkel, Joost Vanoverbeke, W. Van Doorslaer, Heidrun Feuchtmayr, David Atkinson, Brian Moss, Thomas A. Davidson, Carl D. Sayer, L. De MeesterAbstract:Nature Clim. Change 5, 665–668 (2015); published online 27 April 2015; corrected after print 3 September 2015 In the version of this Letter originally published, in Fig. 1a, the boxplot for the Ambient +4 °C treatment was incorrect. This error has been corrected in the online versions.
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Rapid evolution of thermal tolerance in the Water Flea Daphnia
Nature Climate Change, 2015Co-Authors: Aurora N. Geerts, Bram Vanschoenwinkel, Joost Vanoverbeke, W. Van Doorslaer, Heidrun Feuchtmayr, David Atkinson, Brian Moss, Thomas A. Davidson, Carl D. Sayer, L. De MeesterAbstract:A manipulation experiment, combined with reconstructed evolutionary history from a dormant egg bank found in recent lake sediments, reveals that Water Fleas (Daphnia) can exhibit a rapid increase in their capacity to tolerate higher temperatures.
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Thermal Genetic Adaptation in the Water Flea Daphnia and its Impact: An Evolving Metacommunity Approach
Integrative and comparative biology, 2011Co-Authors: Luc De Meester, Aurora N. Geerts, W. Van Doorslaer, Luisa Orsini, Robby StoksAbstract:Genetic adaptation to temperature change can impact responses of populations and communities to global warming. Here we integrate previously published results on experimental evolution trials with follow-up experiments involving the Water Flea Daphnia as a model system. Our research shows (1) the capacity of natural populations of this species to genetically adapt to changes in temperature in a time span of months to years, (2) the context-dependence of these genetic changes, emphasizing the role of ecology and community composition on evolutionary responses to climatic change, and (3) the impact of micro-evolutionary changes on immigration success of preadapted genotypes. Our study involves (1) experimental evolution trials in the absence and presence of the community of competitors, predators, and parasites, (2) life-table and competition experiments to assess the fitness consequences of micro-evolution, and (3) competition experiments with putative immigrant genotypes. We use these observations as building blocks of an evolving metacommunity to understand biological responses to climatic change. This approach integrates both local and regional responses at both the population and community levels. Finally, we provide an outline of current gaps in knowledge and suggest fruitful avenues for future research.
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Local adaptation to higher temperatures reduces immigration success of genotypes from a warmer region in the Water Flea Daphnia
Global Change Biology, 2009Co-Authors: W. Van Doorslaer, Joost Vanoverbeke, Heidrun Feuchtmayr, David Atkinson, Brian Moss, Mieke Jansen, Cathy Duvivier, Sarah Rousseaux, Bastiaan Jansen, Robby StoksAbstract:There is growing awareness that microevolutionary dynamics may alter ecological processes. Rising temperatures under global change are expected to open windows for establishment of species and genotypes from warmer regions. Yet, microevolutionary tracking of temperature change by local populations may reduce establishment success of these immigrants. We exposed a UK population of the Water Flea, Daphnia magna, to two temperature regimes during a 1.5-year experimental evolution trial, and subsequently compared competitive strength of non-warm-adapted and warm-adapted D. magna in competition with French genotypes. Our results indicate that local microevolutionary responses to global warming may reduce establishment success of immigrant genotypes that are preadapted to warmer climate. Simulation modeling shows that microevolution results in a reduced likelihood and speed of displacement of local populations by immigrant genotypes under realistic immigrant/resident ratios. We conclude that local evolutionary dynamics may shift the relative impact of local and regional processes in response to global change.
