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  • 1.
    Berner, Daniel
    et al.
    Basel, Switzerland.
    Thibert-Plante, Xavier
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Knoxville, TN, USA; Uppsala, Sweden.
    How mechanisms of habitat preference evolve and promote divergence with gene flow2015Ingår i: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 28, nr 9, s. 1641-1655Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Habitat preference may promote adaptive divergence and speciation, yet the conditions under which this is likely are insufficiently explored. We use individual-based simulations to study the evolution and consequence of habitat preference during divergence with gene flow, considering four different underlying genetically based behavioural mechanisms: natal habitat imprinting, phenotype-dependent, competition-dependent and direct genetic habitat preference. We find that the evolution of habitat preference generally requires initially high dispersal, is facilitated by asymmetry in population sizes between habitats, and is hindered by an increasing number of underlying genetic loci. Moreover, the probability of habitat preference to emerge and promote divergence differs greatly among the underlying mechanisms. Natal habitat imprinting evolves most easily and can allow full divergence in parameter ranges where no divergence is possible in the absence of habitat preference. The reason is that imprinting represents a one-allele mechanism of assortative mating linking dispersal behaviour very effectively to local selection. At the other extreme, direct genetic habitat preference, a two-allele mechanism, evolves under restricted conditions only, and even then facilitates divergence weakly. Overall, our results indicate that habitat preference can be a strong reproductive barrier promoting divergence with gene flow, but that this is highly contingent on the underlying preference mechanism.

  • 2. Crispo, Erika
    et al.
    DiBattista, Joseph D.
    Correa, Cristian
    Thibert-Plante, Xavier
    Department of Biology and Redpath Museum, McGill University, Montreal, Quebec, Canada.
    McKellar, Ann E.
    Schwartz, Amy K.
    Berner, Daniel
    De Leon, Luis F.
    Hendry, Andrew P.
    The evolution of phenotypic plasticity in response to anthropogenic disturbance2010Ingår i: Evolutionary Ecology Research, ISSN 1522-0613, E-ISSN 1937-3791, Vol. 12, nr 1, s. 47-66Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Questions: Do evolutionary changes in phenotypic plasticity occur after anthropogenic disturbance? Do these changes tend to be increases or decreases in plasticity? How do these evolutionary patterns differ among taxa and trait types? Does evolution of plasticity change with time since the disturbance?

    Data incorporated: Evolutionary rates for plasticity estimated from 20 studies that have compared a plastic response in two or more populations, at least one of which had experienced an anthropogenic disturbance in nature and at least one of which had not.

    Method of analysis: We estimate evolutionary rates (darwins and haldanes) for plasticity for each study, which represent the amount of evolutionary change in plasticity. We then perform analyses of covariance, with the evolutionary rate numerator (amount of evolutionary change) as a response variable, taxa and trait type as predictor variables, and the amount of evolutionary time as a covariate.

    Conclusions:We find that plasticity has evolved in several cases, including both increases and decreases in the levels of plasticity following anthropogenic disturbances. The typical direction of this evolutionary response depends on an interaction between taxon and trait type. For instance, invertebrates sometimes show the evolution of increased  plasticity for life-history traits, but the evolution of decreased plasticity for morphological traits. Plants, on the other hand, show no trends in the direction of plasticity evolution.

  • 3.
    Dibattista, Joseph D.
    et al.
    Redpath Museum and Department of Biology, McGill University, Montréal, Québec, Canada .
    Feldheim, Kevin A.
    Field Museum, Pritzker Laboratory for Molecular Systematics and Evolution, Chicago, IL, USA.
    Thibert-Plante, Xavier
    Redpath Museum and Department of Biology, McGill University, Montréal, Québec, Canada.
    Gruber, Samuel H.
    Division of Marine Biology and Fisheries, Rosenstiel School of Marine and Atmospheric Science, Miami, FL, USA.
    Hendry, Andrew P.
    Redpath Museum and Department of Biology, McGill University, Montréal, Québec, Canada.
    A genetic assessment of polyandry and breeding-site fidelity in lemon sharks2008Ingår i: Molecular Ecology, ISSN 0962-1083, E-ISSN 1365-294X, Vol. 17, nr 14, s. 3337-3351Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We here employ 11 microsatellite markers and recently developed litter reconstruction methods to infer mating system parameters (i.e. polyandry and breeding-site fidelity) at a lemon shark nursery site in Marquesas Key, Florida. Four hundred and eight juvenile or subadult sharks were genotyped over eight complete breeding seasons. Using this information, we were able to infer family structure, as well as fully or partially reconstruct genotypes of 46 mothers and 163 fathers. Multiple litter reconstruction methods were used, and novel simulations helped define apparent bias and precision of at least some mating system parameters. For Marquesas Key, we find that adult female lemon sharks display high levels of polyandry (81% of all litters sampled) and stronger fidelity to the nursery site than do males. Indeed, few male sharks sired offspring from more than one litter during the course of the study. These findings were quite similar to previous results from another lemon shark nursery site (Bimini, Bahamas), suggesting conserved mating system parameters despite significant variation in early life-history traits (i.e. body size and growth) among sites. The finding of at least some site fidelity in females also supports the need for careful conservation of each nursery.

  • 4.
    Kang, Jung Koo
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. The Center for Quantitative Sciences in Biomedicine, North Carolina State University, Raleigh, NC, USA.
    Thibert-Plante, Xavier
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Eco-evolution in size-structured ecosystems: simulation case study of rapid morphological changes in alewife2017Ingår i: BMC Evolutionary Biology, ISSN 1471-2148, E-ISSN 1471-2148, Vol. 17, artikel-id 58Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Over the last 300 years, interactions between alewives and zooplankton communities in several lakes in the U.S. have caused the alewives' morphology to transition rapidly from anadromous to landlocked. Lakes with landlocked alewives contain smaller-bodied zooplankton than those without alewives. Landlocked adult alewives display smaller body sizes, narrower gapes, smaller inter-gill-raker spacings, reach maturity at an earlier age, and are less fecund than anadromous alewives. Additionally, landlocked alewives consume pelagic prey exclusively throughout their lives whereas anadromous alewives make an ontogenetic transition from pelagic to littoral prey. These rapid, well-documented changes in the alewives' morphology provide important insights into the morphological evolution of fish. Predicting the morphological evolution of fish is crucial for fisheries and ecosystem management, but the involvement of multiple trophic interactions make predictions difficult. To obtain an improved understanding of rapid morphological change in fish, we developed an individual-based model that simulated rapid changes in the body size and gill-raker count of a fish species in a hypothetical, size-structured prey community. Model parameter values were based mainly on data from empirical studies on alewives. We adopted a functional trait approach; consequently, the model explicitly describes the relationships between prey body size, alewife body size, and alewife gill-raker count. We sought to answer two questions: ( 1) How does the impact of alewife populations on prey feed back to impact alewife size and gill raker number under several alternative scenarios? ( 2) Will the trajectory of the landlocked alewives' morphological evolution change after 150-300 years in freshwater? 

    Results: Over the first 250 years, the alewives' numbers of gill-rakers only increased when reductions in their body size substantially improved their ability to forage for small prey. Additionally, alewives' gill- raker counts increased more rapidly as the adverse effects of narrow gill- raker spacings on foraging for large prey weremade less severe. For the first150- 250 years, alewives' growth decreased monotonically, and their gill- raker number increased monotonically. After the first 150-250 years, however, the alewives exhibited multiple evolutionary morphological trajectories in different trophic settings. In several of these settings, their evolutionary trajectories even reversed after the first 150-250 years. 

    Conclusions: Alewives affected the abundance and morphology of their prey, which in turn changed the abundance and morphology of the alewives. Complex low-trophic-level interactions can alter the abundance and characteristics of alewives. This study suggests that the current morphology of recently (similar to 300 years)-landlocked alewives may not represent an evolutionarily stable state.

  • 5.
    Liancourt, P.
    et al.
    Department of Biology, University of Pennsylvania, Philadelphia, USA, and Department of Plant Ecology, University of Tübingen, Tübingen, Germany.
    Choler, P.
    Laboratoire d’Ecologie Alpine, CNRS UMR 5553 and Station Alpine J. Fourier, CNRS UMS 2925, Universit´e de Grenoble, Grenoble, France.
    Gross, N.
    INRA, USC Agripop (CEBC-CNRS), Beauvoir sur Niort, France and CEBC-CNRS (UPR 1934), Beauvoir sur Niort, France.
    Thibert-Plante, Xavier
    National Institute for Mathematical and Biological Synthesis (NIMBioS), University of Tennessee, Knoxville, USA.
    Tielbörger, K.
    Department of Plant Ecology, University of Tübingen, Tübingen, Germany.
    How facilitation may interfere with ecological speciation2012Ingår i: International Journal of Ecology, ISSN 1687-9708, Vol. 2012, nr Special issue on Ecological Speciation, s. Article ID 725487-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Compared to the vast literature linking competitive interactions and speciation, attempts to understand the role of facilitation for evolutionary diversification remain scarce. Yet, community ecologists now recognize the importance of positive interactions within plant communities. Here, we examine how facilitation may interfere with the mechanisms of ecological speciation. We argue that facilitation is likely to (1) maintain gene flow among incipient species by enabling cooccurrence of adapted and maladapted forms in marginal habitats and (2) increase fitness of introgressed forms and limit reinforcement in secondary contact zones. Alternatively, we present how facilitation may favour colonization of marginal habitats and thus enhance local adaptation and ecological speciation. Therefore, facilitation may impede or pave the way for ecological speciation. Using a simple spatially and genetically explicit modelling framework, we illustrate and propose some first testable ideas about how, when, and where facilitation may act as a cohesive force for ecological speciation. These hypotheses and the modelling framework proposed should stimulate further empirical and theoretical research examining the role of both competitive and positive interactions in the formation of incipient species.

  • 6.
    Nonaka, Etsuko
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Metapopulation Research Centre, Department of Biosciences, University of Helsinki, Helsinki, Finland.
    Svanbäck, Richard
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Department of Ecology and Genetics/Limnology, Uppsala University.
    Thibert-Plante, Xavier
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Englund, Göran
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Brännström, Åke
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för matematik och matematisk statistik. Evolution and Ecology Program, International Institute for Applied Systems Analysis, Laxenburg, Austria.
    Mechanisms by which phenotypic plasticity affects adaptive divergence and ecological speciation2015Ingår i: American Naturalist, ISSN 0003-0147, E-ISSN 1537-5323, Vol. 186, nr 5, s. E126-E143Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Phenotypic plasticity is the ability of one genotype to produce different phenotypes depending on environmental conditions. Several conceptual models emphasize the role of plasticity in promoting reproductive isolation and, ultimately, speciation in populations that forage on two or more resources. These models predict that plasticity plays a critical role in the early stages of speciation, prior to genetic divergence, by facilitating fast phenotypic divergence. The ability to plastically express alternative phenotypes may, however, interfere with the early phase of the formation of reproductive barriers, especially in the absence of geographic barriers. Here, we quantitatively investigate mechanisms under which plasticity can influence progress toward adaptive genetic diversification and ecological speciation. We use a stochastic, individual-based model of a predator-prey system incorporating sexual reproduction and mate choice in the predator. Our results show that evolving plasticity promotes the evolution of reproductive isolation under diversifying environments when individuals are able to correctly select a more profitable habitat with respect to their phenotypes (i.e., adaptive habitat choice) and to assortatively mate with relatively similar phenotypes. On the other hand, plasticity facilitates the evolution of plastic generalists when individuals have a limited capacity for adaptive habitat choice. We conclude that plasticity can accelerate the evolution of a reproductive barrier toward adaptive diversification and ecological speciation through enhanced phenotypic differentiation between diverging phenotypes.

  • 7.
    Parrott, Lael
    et al.
    Geomatics and Landscape Ecology Lab, Carleton University, Nesbitt, Building, Ottawa, Ontario, Canada.
    Proulx, Raphael
    Complex Systems Laboratory, Département de géographie, Université de Montréal, C.P., Montréal, QC, Canada.
    Thibert-Plante, Xavier
    Redpath Museum and Department of Biology, McGill University, Montreal, Quebec, Canada.
    Three-dimensional metrics for the analysis of spatiotemporal data in ecology2008Ingår i: Ecological Informatics, ISSN 1574-9541, E-ISSN 1878-0512, Vol. 3, nr 6, s. 343-353Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A suite of simple metrics that can be used to analyse three-dimensional data sets is presented. We show how these metrics can be applied to raster-based, ecological mosaics sampled over uniform time intervals, such as might be obtained from a series of photographs or from repeated spatial sampling in the field. In these analyses, the concept of a 2D landscape “patch” is replaced by a 3D space–time “blob”. The structure of a dataset can be analysed via the characterisation of blobs, using a number of simple composition and configuration metrics. The use of different metrics, including modified versions of some common landscape metrics such as contagion, that describe the distribution of blobs in space and time, is demonstrated using both model and empirical data. With the increasing availability of spatiotemporal data sets in ecology, such three-dimensional metrics may be indispensable tools for the detection and characterization of landscape change in the context of human and naturally caused disturbances.

  • 8.
    Reardon, Erin E.
    et al.
    Biology Department Biology Department, McGill University, Montreal, Quebec, Canada.
    Thibert-Plante, Xavier
    Biology Department and Redpath Museum, McGill University, Montreal, Quebec, Canada.
    Optimal offspring size influenced by the interaction between dissolved oxygen and predation pressure2010Ingår i: Evolutionary Ecology Research, ISSN 1522-0613, E-ISSN 1937-3791, Vol. 12, nr 3, s. 377-387Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Question: How does optimal size at the beginning of the juvenile stage vary with dissolved oxygen and aquatic predator pressure?

    Mathematical methods: An implicit model based on earlier offspring size and number optimality models, using empirical observations to motivate and interpret the results.

    Key assumptions: A stable, density-independent system with high parental care that maximizes maternal fitness, with respect to offspring size and number.

    Predictions: The model predicts a positive relationship between juvenile size and aquatic dissolved oxygen, with respect to maternal fitness and predation pressure. This prediction is based on observations in the literature that smaller fish are less sensitive to low dissolved oxygen and may use low dissolved oxygen habitats as predator refuges.

  • 9.
    Thibert-Plante, Xavier
    et al.
    Physics Department and Geography Department, Université de Montréal, Montréal, Québec, Canada.
    Charbonneau, Paul
    Physics Department, Université de Montréal, Montréal, Québec, Canada.
    Crossover and evolutionary stability in the prisoner’s dilemma2007Ingår i: Evolutionary Computation, ISSN 1063-6560, E-ISSN 1530-9304, Vol. 15, nr 3, s. 321-344Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We examine the role played by crossover in a series of genetic algorithm-based evolutionary simulations of the iterated prisoner's dilemma. The simulations are characterized by extended periods of stability, during which evolutionarily meta-stable strategies remain more or less fixed in the population, interrupted by transient, unstable episodes triggered by the appearance of adaptively targeted predators. This leads to a global evolutionary pattern whereby the population shifts from one of a few evolutionarily metastable strategies to another to evade emerging predator strategies. While crossover is not particularly helpful in producing better average scores, it markedly enhances overall evolutionary stability. We show that crossover achieves this by (1) impeding the appearance and spread of targeted predator strategies during stable phases, and (2) greatly reducing the duration of unstable epochs, presumably by efficient recombination of building blocks to rediscover prior metastable strategies. We also speculate that during stable phases, crossover's operation on the persistently heterogeneous gene pool enhances the survival of useful building blocks, thus sustaining long-range temporal correlations in the evolving population. Empirical support for this conjecture is found in the extended tails of probability distribution functions for stable phase lifetimes.

  • 10.
    Thibert-Plante, Xavier
    et al.
    National Institute for Mathematical and Biological Synthesis, University of Tennessee, Knoxville, TN, USA and Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden.
    Gavrilets, Sergey
    National Institute for Mathematical and Biological Synthesis, University of Tennessee, Knoxville, TN, USA and Department of Ecology and Evolutionary Biology and Department of Mathematics, University of Tennessee, Knoxville, TN, USA .
    Evolution of mate choice and the so-called magic traits in ecological speciation2013Ingår i: Ecology Letters, ISSN 1461-023X, E-ISSN 1461-0248, Vol. 16, nr 8, s. 1004-1013Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Non-random mating provides multiple evolutionary benefits and can result in speciation. Biological organisms are characterised by a myriad of different traits, many of which can serve as mating cues. We consider multiple mechanisms of non-random mating simultaneously within a unified modelling framework in an attempt to understand better which are more likely to evolve in natural populations going through the process of local adaptation and ecological speciation. We show that certain traits that are under direct natural selection are more likely to be co-opted as mating cues, leading to the appearance of magic traits (i.e. phenotypic traits involved in both local adaptation and mating decisions). Multiple mechanisms of non-random mating can interact so that trait co-evolution enables the evolution of non-random mating mechanisms that would not evolve alone. The presence of magic traits may suggest that ecological selection was acting during the origin of new species.

  • 11.
    Thibert-Plante, Xavier
    et al.
    Redpath Museum and Department of Biology, McGill University, Montréal, QC, Canada and National Institute for Mathematical and Biological Synthesis, University of Tennessee, Knoxville, TN, USA.
    Hendry, A. P.
    Redpath Museum and Department of Biology, McGill University, Montréal, QC, Canada.
    Factors influencing progress toward sympatric speciation2011Ingår i: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 24, nr 10, s. 2186-2196Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Many factors could influence progress towards sympatric speciation. Some of the potentially important ones include competition, mate choice and the degree to which alternative sympatric environments (resources) are discrete. What is not well understood is the relative importance of these different factors, as well as interactions among them. We use an individual-based numerical model to investigate the possibilities. Mate choice was modelled as the degree to which male foraging traits influence female mate choice. Competition was modelled as the degree to which individuals with different phenotypes compete for portions of the resource distribution. Discreteness of the environment was modelled as the degree of bimodality of the underlying resource distribution. We find that strong mate choice was necessary, but not sufficient, to cause sympatric speciation. In addition, sympatric speciation was most likely when the resource distribution was strongly bimodal and when competition among different phenotypes was intermediate. Even under these ideal conditions, however, sympatric speciation occurred only a fraction of the time. Sympatric speciation owing to competition on unimodal resource distributions was also possible, but much less common. In all cases, stochasticity played an important role in determining progress towards sympatric speciation, as evidenced by variation in outcomes among replicate simulations for a given set of parameter values. Overall, we conclude that the nature of competition is much less important for sympatric speciation than is the nature of mate choice and the underlying resource distribution. We argue that an increased understanding of the promoters and inhibitors of sympatric speciation is best achieved through models that simultaneously evaluate multiple potential factors.

  • 12.
    Thibert-Plante, Xavier
    et al.
    Redpath Museum and Department of Biology, McGill University, Montreal, QC, Canada.
    Hendry, A. P.
    Redpath Museum and Department of Biology, McGill University, Montréal, QC, Canada.
    Five questions on ecological speciation addressed with individual-based simulations2009Ingår i: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 22, nr 1, s. 109-123Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We use an individual-based simulation model to investigate factors influencing progress toward ecological speciation. We find that environmental differences can quickly lead to the evolution of substantial reproductive barriers between a population colonizing a new environment and the ancestral population in the old environment. Natural selection against immigrants and hybrids was a major contributor to this isolation, but the evolution of sexual preference was also important. Increasing dispersal had both positive and negative effects on population size in the new environment and had positive effects on natural selection against immigrants and hybrids. Genetic divergence at unlinked, neutral genetic markers was low, except when environmental differences were large and sexual preference was present. Our results highlight the importance of divergent selection and adaptive divergence for ecological speciation. At the same time, they reveal several interesting nonlinearities in interactions between environmental differences, sexual preference, dispersal and population size.

  • 13.
    Thibert-Plante, Xavier
    et al.
    Redpath Museum and Department of Biology, McGill University, Montre´al, QC, Canada.
    Hendry, A. P.
    Redpath Museum and Department of Biology, McGill University, Montre´al, QC, Canada.
    The consequences of phenotypic plasticity for ecological speciation2011Ingår i: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 24, nr 2, s. 326-342Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We use an individual-based numerical simulation to study the effects of phenotypic plasticity on ecological speciation. We find that adaptive plasticity evolves readily in the presence of dispersal between populations from different ecological environments. This plasticity promotes the colonization of new environments but reduces genetic divergence between them. We also find that the evolution of plasticity can either enhance or degrade the potential for divergent selection to form reproductive barriers. Of particular importance here is the timing of plasticity in relation to the timing of dispersal. If plasticity is expressed after dispersal, reproductive barriers are generally weaker because plasticity allows migrants to be better suited for their new environment. If plasticity is expressed before dispersal, reproductive barriers are either unaffected or enhanced. Among the potential reproductive barriers we considered, natural selection against migrants was the most important, primarily because it was the earliest-acting barrier. Accordingly, plasticity had a much greater effect on natural selection against migrants than on sexual selection against migrants or on natural and sexual selection against hybrids. In general, phenotypic plasticity can strongly alter the process of ecological speciation and should be considered when studying the evolution of reproductive barriers.

  • 14.
    Thibert-Plante, Xavier
    et al.
    Redpath Museum and Department of Biology, 859 Sherbrooke St. West, McGill University, Montréal, QC, Canada H3A 2K6.
    Hendry, Andrew P.
    Redpath Museum and Department of Biology, 859 Sherbrooke St. West, McGill University, Montréal, QC, Canada H3A 2K6.
    When can ecological speciation be detected with neutral loci?2010Ingår i: Molecular Ecology, ISSN 0962-1083, E-ISSN 1365-294X, Vol. 19, nr 11, s. 2301-2314Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    It is not yet clear under what conditions empirical studies can reliably detect progress toward ecological speciation through the analysis of allelic variation at neutral loci. We use a simulation approach to investigate the range of parameter space under which such detection is, and is not, likely. We specifically test for the conditions under which divergent natural selection can cause a ‘generalized barrier to gene flow’ that is present across the genome. Our individual-based numerical simulations focus on how population divergence at neutral loci varies in relation to recombination rate with a selected locus, divergent selection on that locus, migration rate and population size. We specifically test whether genetic differences at neutral markers are greater between populations in different environments than between populations in similar environments. We find that this expected signature of ecological speciation can be detected under part of the parameter space, most consistently when divergent selection is strong and migration is intermediate. By contrast, the expected signature of ecological speciation is not reliably detected when divergent selection is weak or migration is low or high. These findings provide insights into the strengths and weaknesses of using neutral markers to infer ecological speciation in natural systems.

  • 15.
    Thibert-Plante, Xavier
    et al.
    Redpath Museum and Department of Biology, McGill University, Montréal, Québec, Canada.
    Parrott, Lael
    Complex Systems Laboratory, Département de Géographie, Université de Montréal, Montréal, Québec, Canada.
    Prisoner’s dilemma and clusters on small-world networks2007Ingår i: Complexity, ISSN 1076-2787, E-ISSN 1099-0526, Vol. 12, nr 6, s. 22-36Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The structure of interaction plays an important role in the outcome of evolutionary games. This study investigates the evolution of stochastic strategies of the prisoner's dilemma played on structures ranging from lattices to small world networks. Strategies and payoffs are analyzed as a function of the network characteristics of the node they are playing on. Nodes with lattice-like neighborhoods tend to perform better than the nodes modified during the rewiring process of the construction of the small-world network.

  • 16.
    Thibert-Plante, Xavier
    et al.
    Centre de Recherche en Calcul Appliqué, CERCA, Montréal, QC, Canada.
    Yuen, D A
    Department of Geology and Geophysics and Minnesota Supercomputer Institute, University of Minnesota, Minneapolis, MN, USA.
    Vincent, A P
    Centre de Recherche en Calcul Appliqué, CERCA, Montréal, QC, Canada and Département de Physique, Université de Montréal, Montréal, QC, Canada.
    A simple spectral algorithm for solving large-scale Poisson equation in 2D2003Ingår i: Computer Physics Communications, ISSN 0010-4655, E-ISSN 1879-2944, Vol. 154, nr 2, s. 89-97Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We show that it is possible with easy-to-program algorithms to reach spatial resolutions of the order of 108 grid points for computing the electric potential on 2D periodic lattices, such as the Si(111)7×7 surface. We have used a spectral Fourier technique and parallelized FFTs with OPEN_MP on SGI machines. This method can be easily extended to 3D.

  • 17.
    Zhang, Lai
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för matematik och matematisk statistik. School of Mathematical Science, Yangzhou University 225002, Yangzhou, China.
    Thibert-Plante, Xavier
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Ripe, Jorgen
    Svanback, Richard
    Brännström, Åke
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för matematik och matematisk statistik. Evolution and Ecology Program, International Institute for Applied Systems Analysis A-2361, Laxenburg, Austria.
    Biodiversity loss through speciation collapse: Mechanisms, warning signals, and possible rescue2019Ingår i: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 73, nr 8, s. 1504-1516Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Speciation is the process that generates biodiversity, but recent empirical findings show that it can also fail, leading to the collapse of two incipient species into one. Here, we elucidate the mechanisms behind speciation collapse using a stochastic individual-based model with explicit genetics. We investigate the impact of two types of environmental disturbance: deteriorated visual conditions, which reduce foraging ability and impede mate choice, and environmental homogenization, which restructures ecological niches. We find that: (1) Species pairs can collapse into a variety of forms including new species pairs, monomorphic or polymorphic generalists, or single specialists. Notably, polymorphic generalist forms may be a transient stage to a monomorphic population; (2) Environmental restoration enables species pairs to reemerge from single generalist forms, but not from single specialist forms; (3) Speciation collapse is up to four orders of magnitude faster than speciation, while the reemergence of species pairs can be as slow as de novo speciation; (4) Although speciation collapse can be predicted from either demographic, phenotypic, or genetic signals, observations of phenotypic changes allow the most general and robust warning signal of speciation collapse. We conclude that factors altering ecological niches can reduce biodiversity by reshaping the ecosystem's evolutionary attractors.

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