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evolutionary simulation of Contractors' Learning and Behavior under Two Bid-Tendering Approaches

JOURNAL OF MANAGEMENT IN ENGINEERING 2016年第2期32卷 1-13页

作者： Awwad, Rita Lebanese Amer Univ Dept Civil Engn POB 36 Byblos Lebanon

Bidding and determining the optimum markup are two major decisions that a contractor has to think about thoroughly when faced with a new project. Several bidding models have been presented in the literature to help contractors make these two decisions;however, they mostly considered the perspective of one contractor bidding on a single project, obscuring the interaction and learning components among contractors and the observation of emergent bidding patterns at both individual and aggregate levels. This research uses an evolutionary approach to model construction-bidding market dynamics and study the effect of contractors' risk attitude on their markups, and on the long-term progression of bid prices under two bid-tendering approaches, namely the low and average bid methods. simulation results showed that the most risk-tolerant contractors submit the lowest bid prices under the low-bid method and the highest prices under the average bid method. Moreover, the low-bid approach revealed long-term equilibrium in tendered prices whereas the average bid method reflected a gradual bid-price increase. (C) 2015 American Society of Civil Engineers.

关键词： evolutionary simulation Low bid method Average bid method Markup Risk aversion Profit utility Bid prices

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The role of evolutionary processes in determining trophic structure

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OIKOS 2025年第1期2025卷

作者： Furness, Euan N. Speed, James D. M. Garwood, Russell J. Sutton, Mark D. Univ Cambridge Dept Zool Cambridge England Univ Cambridge Sidney Sussex Coll Cambridge England Norwegian Univ Sci & Technol NTNU Univ Museum Dept Nat Hist Trondheim Norway Univ Manchester Dept Earth & Environm Sci Manchester England Nat Hist Museum London England Imperial Coll London Dept Earth Sci & Engn London England

There are two contrasting hypotheses regarding the drivers of biomass-distribution among trophic levels within ecosystems. Energetic or bottom-up models propose control by supply of energy, either from autotrophy or from the underlying trophic level. Dynamical or top-down models propose control by predators in the overlying trophic level. Although multiple approaches have been used to reconcile these hypotheses, they have rarely considered the evolutionary pressures created by different distributions of biomass. Here, we study the effects of these evolutionary processes using an agent-based, spatially-explicit, eco-evolutionary model. We demonstrate that, when ecosystems are simple and predator-prey relationships between species are fixed and do not evolve, primary productivity limits the number of trophic levels. In this case, the abundance in the top trophic level is always limited by productivity. However, productivity-limited trophic levels subject those below them to limitation by predation, and predation-limited trophic levels allow trophic levels below them to grow until limited by productivity. These results match the expectations of the exploitation ecosystems hypothesis (EEH), which predicts the same pattern of alternating top-down and bottom-up control on trophic levels. When species are able to evolve to adaptively adjust their trophic levels, however, selection is liable to lead to collapse of the trophic pyramid through prey switching. Under these conditions, all trophic levels experience bottom-up control. When the evolution of prey switching is restricted, higher trophic levels are evolutionarily stable and the predictions of the EEH are once again met;the stability of long food chains is thus dependent on the difficulty associated with prey switching. These results suggest that, at least under the combinations of model parameters explored in this study, evolutionary limitation is key to maintaining trophic structure.

关键词： agent-based simulation evolutionary simulation exploitation ecosystems hypothesis foodchain length intraguild predation trophic levels

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What maintains variation in flower accessibility to pollinators in plant communities? A simulation study

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BMC Ecology and Evolution 2025年第1期25卷 1-12页

作者： Keasar, Tamar Wajnberg, Eric Department of Biology University of Haifa – Oranim Tivon Israel INRAE Sophia Antipolis Sophia Antipolis France INRIA Hephaistos Sophia Antipolis France

Background: Flowers in natural plant communities come in many shapes. Flowers with restrictive morphologies are considered complex, because only a subset of pollinators are able to learn how to access their nectar and pollen. Other flowers are easily accessible to diverse pollinating insects, and are regarded as simple. How and why do the two types of flowers coexist in natural plant communities? We developed a spatially explicit evolutionary simulation framework to explore this question. We modeled the dynamics of two types of flowers (‘complex’ and ‘simple’) that differ in accessibility to their simulated pollinators and in food rewards. The flowers are visited by a population of pollinators, which initially possess heritable variation in their ability to learn to forage on the complex flowers. We manipulated the pollinators’ flying distances and the flowers’ overall density, spatial distribution, and starting proportion of simple flowers. We recorded the resulting dynamics of the two flower types in the community, and of the pollinators’ learning rates, over 100 generations. Results: Complex and simple flowers coexisted under all simulated conditions. The steady-state community always contained more simple flowers than complex ones. Complex flowers attained higher frequencies when flowers were highly aggregated than when flower aggregation was low. Long-distance fliers evolved higher learning abilities than short-distance fliers. Pollinator learning abilities, in turn, were positively correlated with the frequency of complex flowers. Conclusions: Frequencies of complex flowers vary among natural plant communities. Our model predicts that this variation is shaped by the plants’ spatial distribution as well as by the cognitive abilities of their pollinators. The model generates novel and testable hypotheses for understanding how diversity in flower shapes is maintained in natural plant communities. © The Author(s) 2025.

关键词： evolutionary simulation Flower morphology Flying distance Learning Monte Carlo simulation Pollination Spatial aggregation Spatially explicit model

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An evolutionary Distance Based on Maximal Unique Matches

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COMMUNICATIONS IN STATISTICS-THEORY AND METHODS 2010年第3期39卷 385-397页

作者： Guyon, Frederic Guenoche, Alain Univ Paris Diderot UMR S 726 F-75005 Paris France CNRS IML Marseille France

We propose to compare complete genomes using a new evolutionary distance based on maximum unique matches (MUMs). We first evaluate the minimum length for a MUM to be significant, and significant MUMs shared by two genomes are then searched with a linear time algorithm. Then, by simulating sets of sequences evolving according to a given tree topology, we prove that this distance varies monotonically with the amount of evolutionary events and, using the NJ method, we get phylogenetic trees very close to the initial ones. Finally, we apply this very fast method to compare bacterial genomes among the Gammaproteobacteria family.

关键词： Bacterial phylogeny evolutionary simulation Genome distance Maximal unique matches

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Warning displays in spiny animals: One (more) evolutionary route to aposematism

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EVOLUTION 2005年第12期59卷 2499-2508页

作者： Speed, MP Ruxton, GD Univ Liverpool Sch Biol Sci Liverpool L69 7ZB Merseyside England Univ Glasgow Inst Biomed & Life Sci Div Environm & Evolut Biol Glasgow G12 8QQ Lanark Scotland

To date, theoretical or laboratory simulations of aposematic evolution in prey animals have focused narrowly on internally stored chemical defense as the source of unprofitability and ignore aposematic advertisement of physical defenses such as spines (and defensive hairs, claws, etc.). This has occurred even though aposematism in spiny animals has been recognized since the 19th century. In this paper we present the first detailed theoretical consideration of aposematism in spiny animals, focusing on questions of initial evolution, costs of display, and coevolution of displays with defenses. Using an individual-based evolutionary model, we found that spines (or similar physical defenses) can easily evolve without aposematism, but when spines do evolve, aposematic displays can also easily evolve if they help to make the prey animal distinctive and if they draw attention to the physical threat. When aposematic displays evolve, they cause reduced investment in costly spines, so that, in addition to signaling unprofitability, aposematic display may enhance the cost-effectiveness of antipredator defenses (one exception to this conclusion is if the display is itself as costly as the defense). For animals with stinging spines, combining physical and chemical defense, the evolution of aposematic display may lead to reduced investment in the toxin compared to the spine. This occurs because spines act as both secondary (repellent) defenses and as primary defenses (their own visible, honest advertisement), whereas internally stored toxins only (generally) act as repellent secondary defenses. We argue that conspicuous aposematism in spines functions as an attention-getting mechanism, whereas conspicuous aposematic display in purely toxic animals may be explained by signal reliability arguments. Finally, one (more) route by which aposematism may initially evolve is by spiny rather than purely chemically defended species, spreading to species with other forms of secondary defense

关键词： aposematism coevolution evolutionary simulation physical defense predation secondary defense

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evolutionary modelling of feed forward loops in gene regulatory networks

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BIOSYSTEMS 2008年第1期91卷 231-244页

作者： Cooper, Max B. Loose, Matthew Brookfield, John F. Y. Univ Nottingham Sch Biol Inst Genet Queens Med Ctr Nottingham NG7 2UH England

Feed forward loops (FFLs) are gene regulatory network motifs. They exist in different types, defined by the signs of the effects of genes in the motif on one another. We examine 36 feed forward loops in Escherichia coli, using evolutionary simulations to predict the forms of FFL expected to evolve to generate the pattern of expression of the output gene. These predictions are tested using likelihood ratios, comparing likelihoods of the observed FFL structures with their likelihoods under null models. The very high likelihood ratios generated, of over 10(11), suggest that evolutionary simulation is a valuable component in the explanation of FFL structure. (C) 2007 Elsevier Ireland Ltd. All rights reserved.

关键词： feed forward loops evolutionary simulation regulatory networks motifs likelihood ratios

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Consequences of Single-Locus and Tightly Linked Genomic Architectures for evolutionary Responses to Environmental Change

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JOURNAL OF HEREDITY 2020年第4期111卷 319-332页

作者： Oomen, Rebekah A. Kuparinen, Anna Hutchings, Jeffrey A. Univ Oslo Ctr Ecol & Evolutionary Synth Oslo Norway Univ Agder Ctr Coastal Res Kristiansand Norway Univ Jyvaskyla Dept Biol & Environm Sci Jyvaskyla Finland Dalhousie Univ Dept Biol Halifax NS Canada Inst Marine Res Flodevigen Marine Res Stn His Norway

Genetic and genomic architectures of traits under selection are key factors influencing evolutionary ***, knowledge of their impacts has been limited by a widespread assumption that most traits are controlled by unlinked polygenic architectures. Recent advances in genome sequencing and eco-evolutionary modeling are unlocking the potential for integrating genomic information into predictions of population responses to environmental change. Using eco-evolutionary simulations, we demonstrate that hypothetical single-locus control of a life history trait produces highly variable and unpredictable harvesting-induced evolution relative to the classically applied nnultilocus model. Single-locus control of complex traits is thought to be uncommon, yet blocks of linked genes, such as those associated with some types of structural genomic variation, have emerged as taxonomically widespread phenomena. Inheritance of linked architectures resembles that of single loci, thus enabling single-locus-like modeling of polygenic ***, the number of loci, their effect sizes, and the degree of linkage among them all occur along a continuum. We review how linked architectures are often associated, directly or indirectly, with traits expected to be under selection from anthropogenic stressors and are likely to play a large role in adaptation to environmental disturbance. We suggest using single-locus models to explore evolutionary extremes and uncertainties when the trait architecture is unknown, refining parameters as genomic information becomes available, and explicitly incorporating linkage among loci when possible. By overestimating the complexity (e.g., number of independent loci) of the genomic architecture of traits under selection, we risk underestimating the complexity (e.g., nonlinearity) of their evolutionary dynamics.

关键词： climate change evolutionary simulation genetic architecture linkage disequilibrium recombination rate structural genomic variation

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Predicting evolutionary responses to interspecific interference in the wild

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ECOLOGY LETTERS 2020年第2期23卷 221-230页

作者： Grether, Gregory F. Drury, Jonathan P. Okamoto, Kenichi W. McEachin, Shawn Anderson, Christopher N. Univ Calif Los Angeles Dept Ecol & Evolutionary Biol Los Angeles CA 90032 USA Univ Durham Dept Biosci Durham England Univ St Thomas Dept Biol St Paul MN USA Dominican Univ Dept Biol Sci River Forest IL 60305 USA

Many interspecifically territorial species interfere with each other reproductively, and in some cases, aggression towards heterospecifics may be an adaptive response to interspecific mate competition. This hypothesis was recently formalised in an agonistic character displacement (ACD) model which predicts that species should evolve to defend territories against heterospecific rivals above a threshold level of reproductive interference. To test this prediction, we parameterised the model with field estimates of reproductive interference for 32 sympatric damselfly populations and ran evolutionary simulations. Asymmetries in reproductive interference made the outcome inherently unpredictable in some cases, but 80% of the model's stable outcomes matched levels of heterospecific aggression in the field, significantly exceeding chance expectations. In addition to bolstering the evidence for ACD, this paper introduces a new, predictive approach to testing character displacement theory that, if applied to other systems, could help in resolving long-standing questions about the importance of character displacement processes in nature.

关键词： Character displacement competitor recognition evolutionary simulation individual-based model interference competition heterospecific aggression interspecific aggression reproductive interference species recognition

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An evolutionary benefit from misperception in foraging behaviour

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3rd Australian Conference on Artificial Life

作者： Brumley, Lachlan Korb, Kevin B. Kopp, Carlo Monash Univ Clayton Sch Informat Technol Clayton Vic 3168 Australia

ISBN: (纸本)9783540769309

Misperception is a common cause of error for individuals and organisations. Conventional wisdom suggests that its effects are detrimental to the misperceiver or its society as a whole. However, in some circumstances misperception can provide a benefit either by diversifying the behaviour of a population or by discouraging behaviour that has a negative impact on the population. In such cases adaptive pressures will drive the population to evolve a probability of misperception that is optimal for that environment. We explore this hypothesis using an evolutionary artificial life simulation.

关键词： artificial life misperception evolutionary simulation

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Emergence of Altruism Behavior for Multi Feeding Areas in Army Ant Social evolutionary System

Emergence of Altruism Behavior for Multi Feeding Areas in Ar...

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IEEE International Conference on Systems, Man, and Cybernetics (SMC)

作者： Ichimura, Takumi Uemoto, Takuya Hara, Akira Prefecture Univ Hiroshima Dept Management & Syst Hiroshima 7348558 Japan Hiroshima City Univ Grad Sch Informat Sci Hiroshima 7313194 Japan

ISBN: (纸本)9781479938407

Army ants perform the altruism that an ant sacrifices its own well-being for the benefit of another ants. Army ants build bridges using their own bodies along the path from a food to the nest. We developed the army ant inspired social evolutionary system which can perform the altruism. The system has 2 kinds of ant agents, 'Major ant' and 'Minor ant' and the ants communicate with each other via pheromones. One ants can recognize them as the signals from the other ants. The pheromones evaporate with the certain ratio and diffused into the space of neighbors stochastically. If the optimal bridge is found, the path through the bridge is the shortest route from foods to the nest. We define the probability for an ant to leave a bridge at a low occupancy condition of ants and propose the constructing method of the optimal route. In this paper, the behaviors of ant under the environment with two or more feeding spots are observed. Some experimental results show the behaviors of great interest with respect to altruism of ants. The description in some computer simulation is reported in this paper.

关键词： Army Ants Altruism Behavior Multi Agent System evolutionary simulation Swarm library

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