scholarly journals Multiscale selection in spatially structured populations

2021 ◽  
Author(s):  
Hilje M. Doekes ◽  
Rutger Hermsen
Keyword(s):  
Natural Selection ◽  
Spatial Structure ◽  
Spatial Scales ◽  
Local Environment ◽  
Structured Populations ◽  
Mathematical Framework ◽  
Spatially Structured Populations ◽  
Local Environments ◽  
Local Selection ◽  
Selection Framework

The spatial structure of natural populations is key to many of their evolutionary processes. Formal theories analysing the interplay between natural selection and spatial structure have mostly focused on populations divided into distinct, non-overlapping groups. Most populations, however, are not structured in this way, but rather (self-)organise into dynamic patterns unfolding at various spatial scales. Here, we present a mathematical framework that quantifies how patterns and processes at different spatial scales contribute to natural selection in such populations. To that end, we define the Local Selection Differential (LSD): a measure of the selection acting on a trait within a given local environment. Based on the LSD, natural selection in a population can be decomposed into two parts: the contribution of local selection, acting within local environments, and the contribution of interlocal selection, acting among them. Varying the size of the local environments subsequently allows one to measure the contribution of each length scale. To illustrate the use of this new multiscale selection framework, we apply it to two simulation models of the evolution of traits known to be affected by spatial population structure: altruism and pathogen transmissibility. In both models, the spatial decomposition of selection reveals that local and interlocal selection can have opposite signs, thus providing a mathematically rigorous underpinning to intuitive explanations of how processes at different spatial scales may compete. It furthermore identifies which length scales - and hence which patterns - are relevant for natural selection. The multiscale selection framework can thus be used to address complex questions on evolution in spatially structured populations.

scholarly journals Between migration load and evolutionary rescue: dispersal, adaptation and the response of spatially structured populations to environmental change

2014 ◽  
Vol 281 (1778) ◽  
pp. 20132795 ◽  
Author(s):  
Elizabeth C. Bourne ◽  
Greta Bocedi ◽  
Justin M. J. Travis ◽  
Robin J. Pakeman ◽  
Rob W. Brooker ◽  
...  
Keyword(s):  
Evolutionary Dynamics ◽  
Structured Populations ◽  
Evolutionary Potential ◽  
Beneficial Effects ◽  
Individual Fitness ◽  
Spatially Structured Populations ◽  
Local Selection ◽  
Evolutionary Response ◽  
Evolutionary Rescue ◽  
Opposing Effects

The evolutionary potential of populations is mainly determined by population size and available genetic variance. However, the adaptability of spatially structured populations may also be affected by dispersal: positively by spreading beneficial mutations across sub-populations, but negatively by moving locally adapted alleles between demes. We develop an individual-based, two-patch, allelic model to investigate the balance between these opposing effects on a population's evolutionary response to rapid climate change. Individual fitness is controlled by two polygenic traits coding for local adaptation either to the environment or to climate. Under conditions of selection that favour the evolution of a generalist phenotype (i.e. weak divergent selection between patches) dispersal has an overall positive effect on the persistence of the population. However, when selection favours locally adapted specialists, the beneficial effects of dispersal outweigh the associated increase in maladaptation for a narrow range of parameter space only (intermediate selection strength and low linkage among loci), where the spread of beneficial climate alleles is not strongly hampered by selection against non-specialists. Given that local selection across heterogeneous and fragmented landscapes is common, the complex effect of dispersal that we describe will play an important role in determining the evolutionary dynamics of many species under rapidly changing climate.

scholarly journals Antisocial rewarding in structured populations

2016 ◽  
Author(s):  
Miguel dos Santos ◽  
Jorge Peña
Keyword(s):  
Spatial Structure ◽  
Social Interactions ◽  
Structured Populations ◽  
Theoretic Model ◽  
Mixed Strategies ◽  
Weak Selection ◽  
The Public ◽  
Spatially Structured Populations ◽  
Game Theoretic ◽  
Game Theoretic Model

ABSTRACTCooperation in collective action dilemmas usually breaks down in the absence of additional incentive mechanisms. This tragedy can be escaped if cooperators have the possibility to invest in reward funds that are shared exclusively among cooperators(prosocial rewarding). Yet, the presence of defectors who do not contribute to the public good but do reward themselves(antisocial rewarding) deters cooperation in the absence of additional countermeasures. A recent simulation study suggests that spatial structure is sufficient to prevent antisocial rewarding from deterring cooperation. Here we reinvestigate this issue assuming mixed strategies and weak selection on a game-theoretic model of social interactions, which we also validate using individual-based simulations. We show that increasing reward funds facilitates the maintenance of prosocial rewarding but prevents its evolution from rare, and that spatial structure can sometimes select against the evolution of prosocial rewarding. Our results suggest that, even in spatially structured populations, additional mechanisms are required to prevent antisocial rewarding from deterring cooperation in public goods dilemmas.

scholarly journals Vector dynamics influence spatially imperfect genetic interventions against disease

2020 ◽  
Author(s):  
Mete K Yuksel ◽  
Christopher H Remien ◽  
Bandita Karki ◽  
James J Bull ◽  
Stephen M Krone
Keyword(s):  
Spatial Structure ◽  
Mathematical Models ◽  
Human Movement ◽  
Structured Populations ◽  
Vector Borne Diseases ◽  
Spatially Structured Populations ◽  
Parasite Reproduction ◽  
Vector Borne ◽  
Genetic Interventions ◽  
Imperfect Coverage

Abstract Background and objectives Genetic engineering and similar technologies offer promising new approaches to controlling human diseases by blocking transmission from vectors. However, in spatially structured populations, imperfect coverage of the vector will leave pockets in which the parasite may persist. Movement by humans may disrupt this local persistence and facilitate eradication when these pockets are small, spreading parasite reproduction outside unprotected areas and into areas that block its reproduction. Here we consider the sensitivity of this process to biological details: do simple generalities emerge that may facilitate interventions? Methodology We develop formal mathematical models of this process similar to standard Ross-Macdonald models, but (i) specifying spatial structure of two patches, with vector transmission blocked in one patch but not in the other, (ii) allowing temporary human movement (travel instead of migration), and (iii) considering two different modes of mosquito biting. Results We find that there is no invariant effect of disrupting spatial structure with travel. For both biting models, travel out of the unprotected patch has different consequences than travel by visitors into the patch, but the effects are reversed between the two biting models. Conclusions and implications Overall, the effect of human travel on the maintenance of vector-borne diseases in structured habitats must be considered in light of the actual biology of mosquito abundances, biting dynamics, and human movement patterns. Lay summary Genetic interventions against pathogens transmitted by insect vectors are promising methods of controlling infectious diseases. These interventions may be imperfect, leaving pockets where the parasite persists. How will human movement between protected and unprotected areas affect persistence? Mathematical models developed here show that the answer is ecology-dependent, depending on vector biting behavior.

scholarly journals Range expansion shifts clonal interference patterns in evolving populations

2019 ◽  
Author(s):  
Nikhil Krishnan ◽  
Jacob G. Scott
Keyword(s):  
Infectious Diseases ◽  
Spatial Structure ◽  
Range Expansion ◽  
Drug Response ◽  
Evolutionary Dynamics ◽  
Population Expansion ◽  
Structured Populations ◽  
Population Heterogeneity ◽  
Length Scales ◽  
Spatially Structured Populations

ABSTRACTIncreasingly, predicting and even controlling evolutionary processes is a sought after goal in fields ranging from agriculture, artificial intelligence, astrobiology, oncology, and infectious diseases. However, our ability to predict evolution and plan such interventions in real populations is limited in part by our understanding of how spatial structure modulates evolutionary dynamics. Among current clinical assays applied to predict drug response in infectious diseases, for instance, many do not explicitly consider spatial structure and its influence on phenotypic heterogeneity, despite it being an inextricable characteristic of real populations. As spatially structured populations are subject to increased interference of beneficial mutants compared to their well-mixed counter-parts, among other effects, this population heterogeneity and structure may non-trivially impact drug response. In spatially-structured populations, the extent of this mutant interference is density dependent and thus varies with relative position within a meta-population in a manner modulated by mutant frequency, selection strength, migration speed, and habitat length, among other factors. In this study, we examine beneficial mutant fixation dynamics along the front of an asexual population expanding its range. We observe that multiple distinct evolutionary regimes of beneficial mutant origin-fixation dynamics are maintained at characteristic length scales along the front of the population expansion. Using an agent-based simulation of range expansion with mutation and selection in one dimension, we measure these length scales across a range of population sizes, selection strengths, and mutation rates. Furthermore, using simple scaling arguments to adapt theory from well-mixed populations, we find that the length scale at the tip of the front within which ‘local’ mutant fixation occurs in a successive mode decreases with increasing mutation rate, as well as population size in a manner predicted by our derived analytic expression. Finally, we discuss the relevance of our findings to real cellular populations, arguing that this conserved region of successive mutant fixation dynamics at the wave tip can be exploited by emerging evolutionary control strategies.

scholarly journals Evolutionary dynamics of collective action in spatially structured populations

2014 ◽  
Author(s):  
Jorge Peña ◽  
Georg Nöldeke ◽  
Laurent Lehmann
Keyword(s):  
Collective Action ◽  
Social Evolution ◽  
Economies Of Scale ◽  
Evolutionary Dynamics ◽  
Empirical Studies ◽  
Structured Populations ◽  
Collective Good ◽  
Mathematical Framework ◽  
Spatially Structured Populations ◽  
Discrete Action

Many models proposed to study the evolution of collective action rely on a formalism that represents social interactions asn-player games between individuals adopting discrete actions such as cooperate and defect. Despite the importance of spatial structure in biological collective action, the analysis ofn-player games games in spatially structured populations has so far proved elusive. We address this problem by considering mixed strategies and by integrating discrete-actionn-player games into the direct fitness approach of social evolution theory. This allows to conveniently identify convergence stable strategies and to capture the effect of population structure by a single structure coefficient, namely, the pairwise (scaled) relatedness among interacting individuals. As an application, we use our mathematical framework to investigate collective action problems associated with the provision of three different kinds of collective goods, paradigmatic of a vast array of helping traits in nature: “public goods” (both providers and shirkers can use the good, e.g., alarm calls), “club goods” (only providers can use the good, e.g., participation in collective hunting), and “charity goods” (only shirkers can use the good, e.g., altruistic sacrifice). We show that relatedness promotes the evolution of collective action in different ways depending on the kind of collective good and its economies of scale. Our findings highlight the importance of explicitly accounting for relatedness, the kind of collective good, and the economies of scale in theoretical and empirical studies of the evolution of collective action.

scholarly journals Vector dynamics influence spatially imperfect genetic interventions against disease

2020 ◽  
Author(s):  
Mete K Yuksel ◽  
Christopher H Remien ◽  
Bandita Karki ◽  
James J Bull ◽  
Stephen M Krone
Keyword(s):  
Spatial Structure ◽  
Mathematical Models ◽  
Human Movement ◽  
Structured Populations ◽  
Vector Borne Diseases ◽  
Spatially Structured Populations ◽  
Parasite Reproduction ◽  
Vector Borne ◽  
Genetic Interventions ◽  
Imperfect Coverage

AbstractBackground and objectivesGenetic engineering and similar technologies offer promising new approaches to controlling human diseases by blocking transmission from vectors. However, in spatially structured populations, imperfect coverage of the vector will leave pockets in which the parasite can persist. Yet movement by humans may disrupt this local persistence and facilitate eradication when these pockets are small, essentially distributing parasite reproduction out of unprotected areas and into areas that block its reproduction.MethodologyWe develop formal mathematical models of this process similar to standard Ross-Macdonald models, but (i) specifying spatial structure of two patches, with transmission blocked in one patch but not in the other, (ii) allowing temporary human movement (travel instead of migration), and (iii) considering two different modes of mosquito biting.ResultsWe find that there is no invariant effect of disrupting spatial structure with travel. For both biting models, travel out of the unprotected patch has different consequences than travel by visitors into the patch, but the effects are reversed between the two biting models.Conclusions and implicationsOverall, the effect of human travel on the maintenance of vector-borne diseases in structured habitats must be considered in light of the actual biology of mosquito abundances and biting dynamics.Lay summaryGenetic interventions against pathogens transmitted by insect vectors are promising methods of controlling infectious diseases. These interventions may be imperfect, leaving pockets where the parasite persists. How will human movement between protected and unprotected areas affect persistence? Mathematical models developed here show that the answer is ecology-dependent, depending on vector biting behavior.

Specific features of long-term domestication of australian crayfish Cherax quadricarinatus in conditions of the western part of Russian Federation

2018 ◽  
Vol 194 ◽  
pp. 188-192
Author(s):  
D. I. Shokasheva
Keyword(s):  
Natural Selection ◽  
Russian Federation ◽  
Natural Populations ◽  
Cherax Quadricarinatus ◽  
Local Environments ◽  
Local Species ◽  
Adaptive Ability

Natural populations of crayfish are in depression in Russia and local species are not cultivated. In this situation, experimental cultivation of allochtonous australian crayfish Cherax quadricarinatus is conducted. This species is distinguished by high reproductive abilities and good consumer properties. It has domesticated in Russia spontaneously and produced 9–10 generations in Astrakhan Region. Certain natural selection in the process of domestication provides adaptive ability of this species to local environments and its capabil­ity to reproduce a viable progeny, so there is no doubts in good prospects of its cultivation in industrial conditions.

scholarly journals Vector-borne disease risk indexes in spatially structured populations

2018 ◽  
Vol 12 (2) ◽  
pp. e0006234 ◽  
Author(s):  
Jorge Velázquez-Castro ◽  
Andrés Anzo-Hernández ◽  
Beatriz Bonilla-Capilla ◽  
Moisés Soto-Bajo ◽  
Andrés Fraguela-Collar
Keyword(s):  
Disease Risk ◽  
Structured Populations ◽  
Vector Borne Disease ◽  
Spatially Structured Populations ◽  
Vector Borne

scholarly journals The pitfalls of biodiversity proxies: Differences in richness patterns of birds, trees and understudied diversity across Amazonia

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Camila D. Ritter ◽  
Søren Faurby ◽  
Dominic J. Bennett ◽  
Luciano N. Naka ◽  
Hans ter Steege ◽  
...  
Keyword(s):  
Species Richness ◽  
Large Scale ◽  
Spatial Scales ◽  
Local Environment ◽  
Life Forms ◽  
Taxonomic Group ◽  
Diversity Gradients ◽  
Richness Patterns ◽  
Taxonomic Groups ◽  
Micro Organisms

AbstractMost knowledge on biodiversity derives from the study of charismatic macro-organisms, such as birds and trees. However, the diversity of micro-organisms constitutes the majority of all life forms on Earth. Here, we ask if the patterns of richness inferred for macro-organisms are similar for micro-organisms. For this, we barcoded samples of soil, litter and insects from four localities on a west-to-east transect across Amazonia. We quantified richness as Operational Taxonomic Units (OTUs) in those samples using three molecular markers. We then compared OTU richness with species richness of two relatively well-studied organism groups in Amazonia: trees and birds. We find that OTU richness shows a declining west-to-east diversity gradient that is in agreement with the species richness patterns documented here and previously for birds and trees. These results suggest that most taxonomic groups respond to the same overall diversity gradients at large spatial scales. However, our results show a different pattern of richness in relation to habitat types, suggesting that the idiosyncrasies of each taxonomic group and peculiarities of the local environment frequently override large-scale diversity gradients. Our findings caution against using the diversity distribution of one taxonomic group as an indication of patterns of richness across all groups.

scholarly journals Weathering the impacts of climate change

2020 ◽  
pp. 227-238
Author(s):  
Brian Helmuth
Keyword(s):  
Climate Change ◽  
Environmental Conditions ◽  
Quantitative Methods ◽  
Heat Waves ◽  
Heat Budget ◽  
Spatial Scales ◽  
Physiological Tolerance ◽  
Physiological Processes ◽  
Local Environments ◽  
Sessile Organisms

Ectothermic organisms experience their local environments in ways that humans can have difficulty conceptualizing. Physics-based (ecomechanical) approaches, for example heat budget models, can lend insights into how an organism’s very local environmental conditions (microclimate) can drive niche-level conditions such as body temperature; these in turn drive physiological processes. Quantitative methods also allow insights into the temporal and spatial scales that may ultimately determine responses to larger-scale environmental change. For example, for small, sessile organisms, microhabitats such as crevices in rocks may provide microrefugia that allow survival during heat waves. As a result, larger-scale recovery following heat waves (rescue effects) may ultimately be influenced by much smaller-scale processes. Ecomechanics techniques also facilitate the use of interventions such as shading that can maintain environmental conditions within physiological tolerance levels.

Sign in / Sign up

Export Citation Format

Share Document