Dynamics and Genealogy of Strains in Spatially Extended Host–Pathogen Models

Rauch, Erik; Sayama, Hiroki; Bar‐Yam, Yaneer

doi:10.1006/jtbi.2003.3127

Cited by 32 publications

(35 citation statements)

References 22 publications

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“…2 shows a typical example of the evolution of and ␦ during a single run. As in previous studies using similar models without communication (8,(10)(11)(12)(13), average transmissibility in the consumer population evolves to fluctuate about a moderate equilibrium value rather than increasing to the ϭ 1 limit as individual-level selection would predict. The maximum trace shows the repeated emergence of highervariants, evidence of individual-level selection winning out at a spatially and temporally local level; however, local extinctions eliminate these strains over the long term (10,12,13).…”

Section: Experiments I: Signal-based Reproductive Restraint Is Favoredsupporting

confidence: 54%

“…The amorphousness of these collections inhibits a quantitative formalization in the case of the simulations discussed here, but the conceptual framework may be a useful one. A time-dependent notion of fitness could be used to quantify the time scale over which selection operates (12,13).…”

Section: Discussionmentioning

confidence: 99%

“…However, experimental and theoretical metapopulation studies, with explicit partitioning into subpopulations, have shown that a lower reproduction rate can confer a long-term selective advantage with regard to population persistence (4)(5)(6)(7). More recent studies of the evolution of reproductive restraint in spatially extended models (8)(9)(10)(11)(12)(13) have demonstrated populations evolving such that individuals have lower reproduction ratios than they might. This restraint results in lower reproductive success for the individual, but over many generations, spatially and genetically correlated lineages avoid extinction that would otherwise result from exhaustion of all available resources.…”

mentioning

confidence: 99%

“…Whereas metapopulation studies display limited reproduction under restricted conditions, the spatially extended models demonstrate such behavior over a very wide range of model parameters (see figure 2 of ref. 13).…”

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confidence: 99%

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The evolution of reproductive restraint through social communication

Werfel

Bar‐Yam

2004

Proc. Natl. Acad. Sci. U.S.A.

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The evolution of altruistic behavior through group selection is generally viewed as possible in theory but unlikely in reality, because individual selection favoring selfish strategies should act more rapidly than group selection favoring cooperation. Here we demonstrate the evolution of altruism, in the form of conditional reproductive restraint based on an explicitly social mechanism, modulated by intrapopulation communication comprising signal and evolved response, in a spatially distributed predatory͞para-sitic͞pathogenic model system. The predatory species consistently comes to exploit a signal implying overcrowding, individuals constraining their reproduction in response, with a corresponding increase in equilibrium reproduction rate in the absence of signal. This signaled restraint arises in a robust way for a range of model spatial systems; it outcompetes non-signal-based restraint and is not vulnerable to subversion by noncooperating variants. In these systems, communication is used to evaluate population density and regulate reproduction accordingly R esearchers from Darwin on have speculated about the evolutionary origins of cooperative behavior. In recent decades, evolutionary explanations have been rooted in individual-and gene-level selection, with selection above these levels considered too weak to play any significant role. Altruistic behavior is explained using inclusive fitness theory, through fundamentally selfish mechanisms such as kin selection, in which individual reproductive success is augmented by success of relatives with shared genes (1-4). However, experimental and theoretical metapopulation studies, with explicit partitioning into subpopulations, have shown that a lower reproduction rate can confer a long-term selective advantage with regard to population persistence (4-7). More recent studies of the evolution of reproductive restraint in spatially extended models (8-13) have demonstrated populations evolving such that individuals have lower reproduction ratios than they might. This restraint results in lower reproductive success for the individual, but over many generations, spatially and genetically correlated lineages avoid extinction that would otherwise result from exhaustion of all available resources. This strain extinction mechanism thus operates as a form of selection above the level of individuals. Whereas metapopulation studies display limited reproduction under restricted conditions, the spatially extended models demonstrate such behavior over a very wide range of model parameters (see figure 2 of ref. 13).Although these studies indicate a kind of altruism, they do not reveal much about interactive social behavior and its effects on the outcomes of selection. Communication is ubiquitous in nature, with organisms using every available medium (auditory͞ vibrational, visual, olfactory͞chemical, electrical, and even tactile signals) for social integration (14, 15), and it is a necessary aspect of true social community. Moreover, social interactions very commonly affect reprod...

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Section: Experiments I: Signal-based Reproductive Restraint Is Favoredsupporting

confidence: 54%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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The evolution of reproductive restraint through social communication

Werfel

Bar‐Yam

2004

Proc. Natl. Acad. Sci. U.S.A.

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“…Home ranges and territories have become important parameters in mathematical models of population dynamics [1,2]. It has also become apparent that inhomogeneities in spatially distributed populations can fundamentally change the dynamics of these systems [3][4][5][6][7][8][9][10]. The spatial variations so common to species in the wild, for instance, is usually attributed to variations in selective forces, i.e., differences in the environment.…”

Section: Introductionmentioning

confidence: 99%

Robustness of spontaneous pattern formation in spatially distributed genetic populations

Aguiar¹,

Baranger²,

Bar‐Yam³

et al. 2003

Braz. J. Phys.

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Spatially distributed genetic populations that compete locally for resources and mate only with sufficiently close neighbors, may give rise to spontaneous pattern formation. Depending on the population parameters, like death rate per generation and size of the competition and mating neighborhoods, isolated groups of individuals, or demes, may appear. The existence of such groups in a population has consequences for genetic diversity and for speciation. In this paper we discuss the robustness of demes formation with respect to two important characteristics of the population: the way individuals recognize the demarcation of the local neighborhoods and the way competition for resources affects the birth rate in an overcrowed situation. Our results indicate that demes are expected to form only for sufficiently sharp demarcations and for sufficiently intense competition. I IntroductionAnimals don't live completely free in the wild because their living space is confined by natural boundaries. The size of the area used is determined often by individual and species needs and environmental limitation. Within the geographic distribution of the species, the range, only areas of suitable habitat are occupied.The living area normally inhabited by an animal is its Home Range. It may belong to a single individual, a mated pair, or a social unit. Within the home range there is often a defended area which is identified as a territory. Typical behavior is usually associated with establishing and defending or protecting the animal's territory. This behavior and the reproductive behavior associated with the territory is unique for each species, and allows several different animal species to live in the same space without rivalry, using different niches within the habitat. Territories are marked so that other members of the species can recognize it. Optical, acoustic, or olfactory cues, or a combination of these are often used. Olfactory demarcation is very common among mammals with a well-developed sense of smell. Urine, feces and products of special scent glands are used alone or in conjunction to mark out the territory.Theoretical biologists have become increasingly aware of the importance of space in ecology, evolution and epidemiology. Home ranges and territories have become important parameters in mathematical models of population dynamics [1,2]. It has also become apparent that inhomogeneities in spatially distributed populations can fundamentally change the dynamics of these systems [3][4][5][6][7][8][9][10]. The spatial variations so common to species in the wild, for instance, is usually attributed to variations in selective forces, i.e., differences in the environment. However, it has been shown that spatially distributed systems can develop inhomogeneity through symmetry breaking and spontaneous pattern formation, independently of environmental inhomogeneity [11,12]. Understanding the mechanisms that may lead to spatial inhomogeneities, and the eventual isolation of groups, is of fundamental importance for the study of g...

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Evolution in spatial predator–prey models and the “prudent predator”: The inadequacy of steady‐state organism fitness and the concept of individual and group selection

et al. 2008

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We review recent research which reveals: (1) how spatially distributed populations avoid overexploiting resources due to the local extinction of over-exploitative variants, and (2) how the conventional understanding of evolutionary processes is violated by spatial populations so that basic concepts, including fitness assignment to individual organisms, are not applicable, and even kin and group selection are unable to describe the mechanism by which exploitative behavior is bounded. To understand these evolutionary processes, a broader view is needed of the properties of multiscale spatiotemporal patterns in organism-environment interactions. We discuss measures that quantify the effects of these interactions on the evolution of a population, including multigenerational fitness and the heritability of the environment.2008 Wiley Periodicals, Inc. Complexity 13: 2008

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Dynamics and Genealogy of Strains in Spatially Extended Host–Pathogen Models

Cited by 32 publications

References 22 publications

The evolution of reproductive restraint through social communication

The evolution of reproductive restraint through social communication

Robustness of spontaneous pattern formation in spatially distributed genetic populations

Evolution in spatial predator–prey models and the “prudent predator”: The inadequacy of steady‐state organism fitness and the concept of individual and group selection

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