Pub Date : 2024-01-14DOI: 10.1016/j.tpb.2024.01.001
Marc Ohlmann , François Munoz , François Massol , Wilfried Thuiller
We develop a spatially realistic model of mutualistic metacommunities that exploits the joint structure of spatial and interaction networks. Assuming that all species have the same colonisation and extinction parameters, this model exhibits a sharp transition between stable non-null equilibrium states and a global extinction state. This behaviour allows defining a threshold on colonisation/extinction parameters for the long-term metacommunity persistence. This threshold, the ‘metacommunity capacity’, extends the metapopulation capacity concept and can be calculated from the spatial and interaction networks without needing to simulate the whole dynamics. In several applications we illustrate how the joint structure of the spatial and the interaction networks affects metacommunity capacity. It results that a weakly modular spatial network and a power-law degree distribution of the interaction network provide the most favourable configuration for the long-term persistence of a mutualistic metacommunity. Our model that encodes several explicit ecological assumptions should pave the way for a larger exploration of spatially realistic metacommunity models involving multiple interaction types.
{"title":"Assessing mutualistic metacommunity capacity by integrating spatial and interaction networks","authors":"Marc Ohlmann , François Munoz , François Massol , Wilfried Thuiller","doi":"10.1016/j.tpb.2024.01.001","DOIUrl":"10.1016/j.tpb.2024.01.001","url":null,"abstract":"<div><p>We develop a spatially realistic model of mutualistic metacommunities that exploits the joint structure of spatial and interaction networks. Assuming that all species have the same colonisation and extinction parameters, this model exhibits a sharp transition between stable non-null equilibrium states and a global extinction state. This behaviour allows defining a threshold on colonisation/extinction parameters for the long-term metacommunity persistence. This threshold, the ‘metacommunity capacity’, extends the metapopulation capacity concept and can be calculated from the spatial and interaction networks without needing to simulate the whole dynamics. In several applications we illustrate how the joint structure of the spatial and the interaction networks affects metacommunity capacity. It results that a weakly modular spatial network and a power-law degree distribution of the interaction network provide the most favourable configuration for the long-term persistence of a mutualistic metacommunity. Our model that encodes several explicit ecological assumptions should pave the way for a larger exploration of spatially realistic metacommunity models involving multiple interaction types.</p></div>","PeriodicalId":49437,"journal":{"name":"Theoretical Population Biology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139467286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-07DOI: 10.1016/j.tpb.2023.12.005
Talia Borofsky , Marcus W. Feldman , Yoav Ram
Although cooperative hunting is widespread among animals, its benefits are unclear. At low frequencies, cooperative hunting may allow predators to escape competition and access bigger prey that could not be caught by a lone cooperative predator. Cooperative hunting is a more successful strategy when it is common, but its spread can result in overhunting big prey, which may have a lower per-capita growth rate than small prey. We construct a one-predator species, two-prey species model in which predators either learn to hunt small prey alone or learn to hunt big prey cooperatively. Predators first learn vertically from parents, then horizontally (i.e. socially) from random individuals or siblings. After horizontal transmission, they hunt with their learning partner if both are cooperative, and otherwise they hunt alone. Cooperative hunting cannot evolve when initially rare unless predators (a) interact with siblings, or (b) horizontally transmit the cooperative behavior to potential hunting partners. Whereas competition for small prey favors cooperative hunting when this cooperation is initially rare, the frequency of cooperative hunting cannot reach 100% unless big prey is abundant. Furthermore, a mutant that increases horizontal learning can invade if cooperative hunting is present, but not at 100%, because horizontal learning allows pairs of predators to have the same strategy. Our results reveal that the interactions between prey availability, social learning, and degree of cooperation among predators may have important effects on ecosystems.
{"title":"Cultural transmission, competition for prey, and the evolution of cooperative hunting","authors":"Talia Borofsky , Marcus W. Feldman , Yoav Ram","doi":"10.1016/j.tpb.2023.12.005","DOIUrl":"10.1016/j.tpb.2023.12.005","url":null,"abstract":"<div><p>Although cooperative hunting is widespread among animals, its benefits are unclear. At low frequencies, cooperative hunting may allow predators to escape competition and access bigger prey that could not be caught by a lone cooperative predator. Cooperative hunting is a more successful strategy when it is common, but its spread can result in overhunting big prey, which may have a lower per-capita growth rate than small prey. We construct a one-predator species, two-prey species model in which predators either learn to hunt small prey alone or learn to hunt big prey cooperatively. Predators first learn vertically from parents, then horizontally (i.e. socially) from random individuals or siblings. After horizontal transmission, they hunt with their learning partner if both are cooperative, and otherwise they hunt alone. Cooperative hunting cannot evolve when initially rare unless predators (a) interact with siblings, or (b) horizontally transmit the cooperative behavior to potential hunting partners. Whereas competition for small prey favors cooperative hunting when this cooperation is initially rare, the frequency of cooperative hunting cannot reach 100% unless big prey is abundant. Furthermore, a mutant that increases horizontal learning can invade if cooperative hunting is present, but not at 100%, because horizontal learning allows pairs of predators to have the same strategy. Our results reveal that the interactions between prey availability, social learning, and degree of cooperation among predators may have important effects on ecosystems.</p></div>","PeriodicalId":49437,"journal":{"name":"Theoretical Population Biology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0040580924000017/pdfft?md5=a2ba6eb2f2f12050d6e18b09a4a9b34e&pid=1-s2.0-S0040580924000017-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139374264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-04DOI: 10.1016/j.tpb.2023.12.004
Asger Hobolth , Carsten Wiuf
Consider the problem of estimating the branch lengths in a symmetric 2-state substitution model with a known topology and a general, clock-like or star-shaped tree with three leaves. We show that the maximum likelihood estimates are analytically tractable and can be obtained from pairwise sequence comparisons. Furthermore, we demonstrate that this property does not generalize to larger state spaces, more complex models or larger trees. Our arguments are based on an enumeration of the free parameters of the model and the dimension of the minimal sufficient data vector. Our interest in this problem arose from discussions with our former colleague Freddy Bugge Christiansen.
{"title":"Maximum likelihood estimation and natural pairwise estimating equations are identical for three sequences and a symmetric 2-state substitution model","authors":"Asger Hobolth , Carsten Wiuf","doi":"10.1016/j.tpb.2023.12.004","DOIUrl":"10.1016/j.tpb.2023.12.004","url":null,"abstract":"<div><p>Consider the problem of estimating the branch lengths in a symmetric 2-state substitution model with a known topology and a general, clock-like or star-shaped tree with three leaves. We show that the maximum likelihood estimates are analytically tractable and can be obtained from pairwise sequence comparisons. Furthermore, we demonstrate that this property does not generalize to larger state spaces, more complex models or larger trees. Our arguments are based on an enumeration of the free parameters of the model and the dimension of the minimal sufficient data vector. Our interest in this problem arose from discussions with our former colleague Freddy Bugge Christiansen.</p></div>","PeriodicalId":49437,"journal":{"name":"Theoretical Population Biology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0040580923000837/pdfft?md5=426e44db4e15cbf41adb83d6740ba283&pid=1-s2.0-S0040580923000837-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139103662","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-01DOI: 10.1016/j.tpb.2023.09.001
Noah A. Rosenberg (Editor-in-Chief)
{"title":"The 2024 Feldman Prize","authors":"Noah A. Rosenberg (Editor-in-Chief)","doi":"10.1016/j.tpb.2023.09.001","DOIUrl":"10.1016/j.tpb.2023.09.001","url":null,"abstract":"","PeriodicalId":49437,"journal":{"name":"Theoretical Population Biology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139082599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-22DOI: 10.1016/j.tpb.2023.12.003
Kaleda K. Denton , Uri Liberman , Marcus W. Feldman
Mathematical models of conformity and anti-conformity have commonly included a set of simplifying assumptions. For example, (1) there are cultural variants in the population, (2) naive individuals observe the cultural variants of adult “role models,” and (3) individuals’ levels of conformity or anti-conformity do not change over time. Three recent theoretical papers have shown that departures from each of these assumptions can produce new population dynamics. Here, we explore cases in which multiple, or all, of these assumptions are violated simultaneously: namely, in a population with variants of a trait where conformity (or anti-conformity) occurs with respect to role models, we study a model in which the conformity rates at each generation are random variables that are independent of the variant frequencies at that generation. For this model a class of symmetric constant equilibria exist, and it is possible that all of these equilibria are simultaneously stochastically locally stable. In such cases, the effect of initial conditions on subsequent evolutionary trajectories becomes very complicated.
顺应与反顺应的数学模型通常包含一系列简化假设。例如:(1)人群中有 m=2 种文化变体;(2)天真的个体观察到 n=3 个成人 "榜样 "的文化变体;(3)个体的顺应或反顺应水平不会随时间而改变。最近的三篇理论论文表明,偏离上述每一个假设都会产生新的种群动态。在这里,我们探讨了同时违反多个或所有这些假设的情况:即在一个有 m 个性状变体的种群中,顺应(或反顺应)发生在 n 个角色模型上,我们研究了一个模型,在这个模型中,每一代的顺应率都是随机变量,与该代的变体频率无关。在这个模型中,存在一类对称的恒定均衡,而且所有这些均衡都有可能同时具有随机局部稳定性。在这种情况下,初始条件对后续进化轨迹的影响变得非常复杂。
{"title":"On random conformity bias in cultural transmission of polychotomous traits","authors":"Kaleda K. Denton , Uri Liberman , Marcus W. Feldman","doi":"10.1016/j.tpb.2023.12.003","DOIUrl":"10.1016/j.tpb.2023.12.003","url":null,"abstract":"<div><p>Mathematical models of conformity and anti-conformity have commonly included a set of simplifying assumptions. For example, (1) there are <span><math><mrow><mi>m</mi><mo>=</mo><mn>2</mn></mrow></math></span> cultural variants in the population, (2) naive individuals observe the cultural variants of <span><math><mrow><mi>n</mi><mo>=</mo><mn>3</mn></mrow></math></span> adult “role models,” and (3) individuals’ levels of conformity or anti-conformity do not change over time. Three recent theoretical papers have shown that departures from each of these assumptions can produce new population dynamics. Here, we explore cases in which multiple, or all, of these assumptions are violated simultaneously: namely, in a population with <span><math><mi>m</mi></math></span> variants of a trait where conformity (or anti-conformity) occurs with respect to <span><math><mi>n</mi></math></span> role models, we study a model in which the conformity rates at each generation are random variables that are independent of the variant frequencies at that generation. For this model a class of symmetric constant equilibria exist, and it is possible that all of these equilibria are simultaneously stochastically locally stable. In such cases, the effect of initial conditions on subsequent evolutionary trajectories becomes very complicated.</p></div>","PeriodicalId":49437,"journal":{"name":"Theoretical Population Biology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0040580923000825/pdfft?md5=d09e55e4173f428cb94f39e6d8b55695&pid=1-s2.0-S0040580923000825-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138992654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-19DOI: 10.1016/j.tpb.2023.12.002
Gustav Feichtinger , Stefan Wrzaczek
About 50 years ago, Keyfitz (1971) asked how much further a growing human population would increase if its fertility rate were immediately to be reduced to replacement level and remain there forever. The reason for demographic momentum is an age–structure inertia due to relatively many potential parents because of past high fertility. Although nobody expects such a miraculous reduction in reproductive behavior, a gradual decline in fertility in rapidly growing populations seems inevitable. As any delay in fertility decline to a stationary level leads to an increase in the momentum, it makes sense to think about the timing and the quantum of the reduction in reproduction. More specifically, we consider an intertemporal trade-off between costly pro- and anti-natalistic measures and the demographic momentum at the end of the planning period. This paper uses the McKendrick–von Foerster partial differential equation of age–structured population dynamics to study a sketched problem in a distributed parameter control framework. Among the results obtained by applying an appropriate extension of Pontryagin’s Maximum Principle are the following: (i) monotony of adaptation efforts to net reproduction rate and convex decrease/concave increase (if initial net reproduction rate exceeds 1/is below 1); and (ii) oscillating efforts and reproduction rate if, additionally, the size of the total population does not deviate from a fixed level.
{"title":"The optimal momentum of population growth and decline","authors":"Gustav Feichtinger , Stefan Wrzaczek","doi":"10.1016/j.tpb.2023.12.002","DOIUrl":"10.1016/j.tpb.2023.12.002","url":null,"abstract":"<div><p>About 50 years ago, Keyfitz (1971) asked how much further a growing human population would increase if its fertility rate were immediately to be reduced to replacement level and remain there forever. The reason for demographic momentum is an age–structure inertia due to relatively many potential parents because of past high fertility. Although nobody expects such a miraculous reduction in reproductive behavior, a gradual decline in fertility in rapidly growing populations seems inevitable. As any delay in fertility decline to a stationary level leads to an increase in the momentum, it makes sense to think about the timing and the quantum of the reduction in reproduction. More specifically, we consider an intertemporal trade-off between costly pro- and anti-natalistic measures and the demographic momentum at the end of the planning period. This paper uses the McKendrick–von Foerster partial differential equation of age–structured population dynamics to study a sketched problem in a distributed parameter control framework. Among the results obtained by applying an appropriate extension of Pontryagin’s Maximum Principle are the following: (i) monotony of adaptation efforts to net reproduction rate and convex decrease/concave increase (if initial net reproduction rate exceeds 1/is below 1); and (ii) oscillating efforts and reproduction rate if, additionally, the size of the total population does not deviate from a fixed level.</p></div>","PeriodicalId":49437,"journal":{"name":"Theoretical Population Biology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0040580923000813/pdfft?md5=d526027ca8b7cfe0772cb47a7ffeda96&pid=1-s2.0-S0040580923000813-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138744318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-12DOI: 10.1016/j.tpb.2023.12.001
Conrad J. Burden , Robert C. Griffiths
Consider the diffusion process defined by the forward equation for and , with an initial condition . This equation was introduced and solved by Feller to model the growth of a population of independently reproducing individuals. We explore important coalescent processes related to Feller’s solution. For any and we calculate the distribution of the random variable , defined as the finite number of ancestors at a time in the past of a sample of size taken from the infinite population of a Feller diffusion at a time since its initiation. In a subcritical diffusion we find the distribution of population and sample coalescent trees from time back, conditional on non-extinction as . In a supercritical diffusion we construct a coalescent tree which has a single founder and derive the distribution of coalescent times.
考虑由正向方程 ut(t,x)=12{xu(t,x)}xx-α{xu(t,x)}x 定义的扩散过程,当 t,x≥0 和 -∞<α<∞ 时,初始条件为 u(0,x)=δ(x-x0)。该方程由费勒提出并求解,用于模拟由独立繁殖个体组成的种群的增长。我们将探讨与费勒求解相关的重要凝聚过程。对于任意 α 和 x0>0,我们计算随机变量 An(s;t)的分布,An(s;t)的定义是:在费勒扩散的无限种群中,自扩散开始以来,在 t 时刻从大小为 n 的样本中抽取的祖先在过去 s 时刻的有限数量。在亚临界扩散中,我们可以找到从时间 t 开始的种群和样本凝聚树的分布,条件是 t→∞ 时没有灭绝。在超临界扩散中,我们构建了一棵具有单一创始者的凝聚树,并推导出凝聚时间的分布。
{"title":"Coalescence and sampling distributions for Feller diffusions","authors":"Conrad J. Burden , Robert C. Griffiths","doi":"10.1016/j.tpb.2023.12.001","DOIUrl":"10.1016/j.tpb.2023.12.001","url":null,"abstract":"<div><p>Consider the diffusion process defined by the forward equation <span><math><mrow><msub><mrow><mi>u</mi></mrow><mrow><mi>t</mi></mrow></msub><mrow><mo>(</mo><mi>t</mi><mo>,</mo><mi>x</mi><mo>)</mo></mrow><mo>=</mo><mfrac><mrow><mn>1</mn></mrow><mrow><mn>2</mn></mrow></mfrac><msub><mrow><mrow><mo>{</mo><mi>x</mi><mi>u</mi><mrow><mo>(</mo><mi>t</mi><mo>,</mo><mi>x</mi><mo>)</mo></mrow><mo>}</mo></mrow></mrow><mrow><mi>x</mi><mi>x</mi></mrow></msub><mo>−</mo><mi>α</mi><msub><mrow><mrow><mo>{</mo><mi>x</mi><mi>u</mi><mrow><mo>(</mo><mi>t</mi><mo>,</mo><mi>x</mi><mo>)</mo></mrow><mo>}</mo></mrow></mrow><mrow><mi>x</mi></mrow></msub></mrow></math></span> for <span><math><mrow><mi>t</mi><mo>,</mo><mi>x</mi><mo>≥</mo><mn>0</mn></mrow></math></span> and <span><math><mrow><mo>−</mo><mi>∞</mi><mo><</mo><mi>α</mi><mo><</mo><mi>∞</mi></mrow></math></span>, with an initial condition <span><math><mrow><mi>u</mi><mrow><mo>(</mo><mn>0</mn><mo>,</mo><mi>x</mi><mo>)</mo></mrow><mo>=</mo><mi>δ</mi><mrow><mo>(</mo><mi>x</mi><mo>−</mo><msub><mrow><mi>x</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>)</mo></mrow></mrow></math></span>. This equation was introduced and solved by Feller to model the growth of a population of independently reproducing individuals. We explore important coalescent processes related to Feller’s solution. For any <span><math><mi>α</mi></math></span> and <span><math><mrow><msub><mrow><mi>x</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>></mo><mn>0</mn></mrow></math></span> we calculate the distribution of the random variable <span><math><mrow><msub><mrow><mi>A</mi></mrow><mrow><mi>n</mi></mrow></msub><mrow><mo>(</mo><mi>s</mi><mo>;</mo><mi>t</mi><mo>)</mo></mrow></mrow></math></span>, defined as the finite number of ancestors at a time <span><math><mi>s</mi></math></span> in the past of a sample of size <span><math><mi>n</mi></math></span> taken from the infinite population of a Feller diffusion at a time <span><math><mi>t</mi></math></span> since its initiation. In a subcritical diffusion we find the distribution of population and sample coalescent trees from time <span><math><mi>t</mi></math></span> back, conditional on non-extinction as <span><math><mrow><mi>t</mi><mo>→</mo><mi>∞</mi></mrow></math></span>. In a supercritical diffusion we construct a coalescent tree which has a single founder and derive the distribution of coalescent times.</p></div>","PeriodicalId":49437,"journal":{"name":"Theoretical Population Biology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S004058092300076X/pdfft?md5=8e598e52b975ba69c518b1ea3087110e&pid=1-s2.0-S004058092300076X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138717155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-02DOI: 10.1016/j.tpb.2023.11.003
Mauricio González-Forero
Natural selection acts on phenotypes constructed over development, which raises the question of how development affects evolution. Classic evolutionary theory indicates that development affects evolution by modulating the genetic covariation upon which selection acts, thus affecting genetic constraints. However, whether genetic constraints are relative, thus diverting adaptation from the direction of steepest fitness ascent, or absolute, thus blocking adaptation in certain directions, remains uncertain. This limits understanding of long-term evolution of developmentally constructed phenotypes. Here we formulate a general, tractable mathematical framework that integrates age progression, explicit development (i.e., the construction of the phenotype across life subject to developmental constraints), and evolutionary dynamics, thus describing the evolutionary and developmental (evo-devo) dynamics. The framework yields simple equations that can be arranged in a layered structure that we call the evo-devo process, whereby five core elementary components generate all equations including those mechanistically describing genetic covariation and the evo-devo dynamics. The framework recovers evolutionary dynamic equations in gradient form and describes the evolution of genetic covariation from the evolution of genotype, phenotype, environment, and mutational covariation. This shows that genotypic and phenotypic evolution must be followed simultaneously to yield a dynamically sufficient description of long-term phenotypic evolution in gradient form, such that evolution described as the climbing of a fitness landscape occurs in “geno-phenotype” space. Genetic constraints in geno-phenotype space are necessarily absolute because the phenotype is related to the genotype by development. Thus, the long-term evolutionary dynamics of developed phenotypes is strongly non-standard: (1) evolutionary equilibria are either absent or infinite in number and depend on genetic covariation and hence on development; (2) developmental constraints determine the admissible evolutionary path and hence which evolutionary equilibria are admissible; and (3) evolutionary outcomes occur at admissible evolutionary equilibria, which do not generally occur at fitness landscape peaks in geno-phenotype space, but at peaks in the admissible evolutionary path where “total genotypic selection” vanishes if exogenous plastic response vanishes and mutational variation exists in all directions of genotype space. Hence, selection and development jointly define the evolutionary outcomes if absolute mutational constraints and exogenous plastic response are absent, rather than the outcomes being defined only by selection. Moreover, our framework provides formulas for the sensitivities of a recurrence and an alternative method to dynamic optimization (i.e., dynamic programming or optimal control) to identify evolutionary outcomes in models with developmentally dynamic traits. These results sho
{"title":"A mathematical framework for evo-devo dynamics","authors":"Mauricio González-Forero","doi":"10.1016/j.tpb.2023.11.003","DOIUrl":"10.1016/j.tpb.2023.11.003","url":null,"abstract":"<div><p>Natural selection acts on phenotypes constructed over development, which raises the question of how development affects evolution. Classic evolutionary theory indicates that development affects evolution by modulating the genetic covariation upon which selection acts, thus affecting genetic constraints. However, whether genetic constraints are relative, thus diverting adaptation from the direction of steepest fitness ascent, or absolute, thus blocking adaptation in certain directions, remains uncertain. This limits understanding of long-term evolution of developmentally constructed phenotypes. Here we formulate a general, tractable mathematical framework that integrates age progression, explicit development (i.e., the construction of the phenotype across life subject to developmental constraints), and evolutionary dynamics, thus describing the evolutionary and developmental (evo-devo) dynamics. The framework yields simple equations that can be arranged in a layered structure that we call the evo-devo process, whereby five core elementary components generate all equations including those mechanistically describing genetic covariation and the evo-devo dynamics. The framework recovers evolutionary dynamic equations in gradient form and describes the evolution of genetic covariation from the evolution of genotype, phenotype, environment, and mutational covariation. This shows that genotypic and phenotypic evolution must be followed simultaneously to yield a dynamically sufficient description of long-term phenotypic evolution in gradient form, such that evolution described as the climbing of a fitness landscape occurs in “geno-phenotype” space. Genetic constraints in geno-phenotype space are necessarily absolute because the phenotype is related to the genotype by development. Thus, the long-term evolutionary dynamics of developed phenotypes is strongly non-standard: (1) evolutionary equilibria are either absent or infinite in number and depend on genetic covariation and hence on development; (2) developmental constraints determine the admissible evolutionary path and hence which evolutionary equilibria are admissible; and (3) evolutionary outcomes occur at admissible evolutionary equilibria, which do not generally occur at fitness landscape peaks in geno-phenotype space, but at peaks in the admissible evolutionary path where “total genotypic selection” vanishes if exogenous plastic response vanishes and mutational variation exists in all directions of genotype space. Hence, selection and development jointly define the evolutionary outcomes if absolute mutational constraints and exogenous plastic response are absent, rather than the outcomes being defined only by selection. Moreover, our framework provides formulas for the sensitivities of a recurrence and an alternative method to dynamic optimization (i.e., dynamic programming or optimal control) to identify evolutionary outcomes in models with developmentally dynamic traits. These results sho","PeriodicalId":49437,"journal":{"name":"Theoretical Population Biology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0040580923000758/pdfft?md5=25cdbdfeeebde0e5d03bffee9e055302&pid=1-s2.0-S0040580923000758-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138479100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-23DOI: 10.1016/j.tpb.2023.11.001
Jorge Peña , Aviad Heifetz , Georg Nöldeke
Cooperation usually becomes harder to sustain as groups become larger because incentives to shirk increase with the number of potential contributors to collective action. But is this always the case? Here we study a binary-action cooperative dilemma where a public good is provided as long as not more than a given number of players shirk from a costly cooperative task. We find that at the stable polymorphic equilibrium, which exists when the cost of cooperation is low enough, the probability of cooperating increases with group size and reaches a limit of one when the group size tends to infinity. Nevertheless, increasing the group size may increase or decrease the probability that the public good is provided at such an equilibrium, depending on the cost value. We also prove that the expected payoff to individuals at the stable polymorphic equilibrium (i.e., their fitness) decreases with group size. For low enough costs of cooperation, both the probability of provision of the public good and the expected payoff converge to positive values in the limit of large group sizes. However, we also find that the basin of attraction of the stable polymorphic equilibrium is a decreasing function of group size and shrinks to zero in the limit of very large groups. Overall, we demonstrate non-trivial comparative statics with respect to group size in an otherwise simple collective action problem.
{"title":"The shirker’s dilemma and the prospect of cooperation in large groups","authors":"Jorge Peña , Aviad Heifetz , Georg Nöldeke","doi":"10.1016/j.tpb.2023.11.001","DOIUrl":"10.1016/j.tpb.2023.11.001","url":null,"abstract":"<div><p>Cooperation usually becomes harder to sustain as groups become larger because incentives to shirk increase with the number of potential contributors to collective action. But is this always the case? Here we study a binary-action cooperative dilemma where a public good is provided as long as not more than a given number of players shirk from a costly cooperative task. We find that at the stable polymorphic equilibrium, which exists when the cost of cooperation is low enough, the probability of cooperating increases with group size and reaches a limit of one when the group size tends to infinity. Nevertheless, increasing the group size may increase or decrease the probability that the public good is provided at such an equilibrium, depending on the cost value. We also prove that the expected payoff to individuals at the stable polymorphic equilibrium (i.e., their fitness) decreases with group size. For low enough costs of cooperation, both the probability of provision of the public good and the expected payoff converge to positive values in the limit of large group sizes. However, we also find that the basin of attraction of the stable polymorphic equilibrium is a decreasing function of group size and shrinks to zero in the limit of very large groups. Overall, we demonstrate non-trivial comparative statics with respect to group size in an otherwise simple collective action problem.</p></div>","PeriodicalId":49437,"journal":{"name":"Theoretical Population Biology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138435318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-22DOI: 10.1016/j.tpb.2023.11.002
Carlos Hernandez-Suarez , Jorge Rabinovich
By quantifying key life history parameters in populations, such as growth rate, longevity, and generation time, researchers and administrators can obtain valuable insights into its dynamics. Although point estimates of demographic parameters have been available since the inception of demography as a scientific discipline, the construction of confidence intervals has typically relied on approximations through series expansions or computationally intensive techniques. This study introduces the first mathematical expression for calculating confidence intervals for the aforementioned life history traits when individuals are unidentifiable and data are presented as a life table. The key finding is the accurate estimation of the confidence interval for , the instantaneous growth rate, which is tested using Monte Carlo simulations with four arbitrary discrete distributions. In comparison to the bootstrap method, the proposed interval construction method proves more efficient, particularly for experiments with a total offspring size below 400. We discuss handling cases where data are organized in extended life tables or as a matrix of vital rates. We have developed and provided accompanying code to facilitate these computations.
{"title":"Exact confidence intervals for population growth rate, longevity and generation time","authors":"Carlos Hernandez-Suarez , Jorge Rabinovich","doi":"10.1016/j.tpb.2023.11.002","DOIUrl":"10.1016/j.tpb.2023.11.002","url":null,"abstract":"<div><p>By quantifying key life history parameters in populations, such as growth rate, longevity, and generation time, researchers and administrators can obtain valuable insights into its dynamics. Although point estimates of demographic parameters have been available since the inception of demography as a scientific discipline, the construction of confidence intervals has typically relied on approximations through series expansions or computationally intensive techniques. This study introduces the first mathematical expression for calculating confidence intervals for the aforementioned life history traits when individuals are unidentifiable and data are presented as a life table. The key finding is the accurate estimation of the confidence interval for <span><math><mi>r</mi></math></span>, the instantaneous growth rate, which is tested using Monte Carlo simulations with four arbitrary discrete distributions. In comparison to the bootstrap method, the proposed interval construction method proves more efficient, particularly for experiments with a total offspring size below 400. We discuss handling cases where data are organized in extended life tables or as a matrix of vital rates. We have developed and provided accompanying code to facilitate these computations.</p></div>","PeriodicalId":49437,"journal":{"name":"Theoretical Population Biology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138435317","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}