scholarly journals Bet-hedging strategies in expanding populations

2018 ◽  
Author(s):  
Martín Paula Villa ◽  
Miguel A. Muñoz ◽  
Simone Pigolotti
Keyword(s):  
Phenotypic Diversity ◽  
Phenotypic Switching ◽  
Bet Hedging ◽  
Uncertain Environments ◽  
Adverse Conditions ◽  
Hedging Strategies ◽  
Spatial Fluctuations ◽  
Fluctuating Environments ◽  
Population Sizes ◽  
Mixed Populations

AbstractIn ecology, species can mitigate their extinction risks in uncertain environments by diversifying individual phenotypes. This observation is quantified by the theory of bet-hedging, which provides a reason for the degree of phenotypic diversity observed even in clonal populations. The theory of bet-hedging in well-mixed populations is rather well developed. However, many species underwent range expansions during their evolutionary history, and the importance of phenotypic diversity in such scenarios still needs to be understood. In this paper, we develop a theory of bet-hedging for populations colonizing new, unknown environments that fluctuate either in space or time. In this case, we find that bet-hedging is a more favorable strategy than in well-mixed populations. For slow rates of variation, temporal and spatial fluctuations lead to different outcomes. In spatially fluctuating environments, bet-hedging is favored compared to temporally fluctuating environments. In the limit of frequent environmental variation, no opportunity for bet-hedging exists, regardless of the nature of the environmental fluctuations. For the same model, bet-hedging is never an advantageous strategy in the well-mixed case, supporting the view that range expansions strongly promote diversification. These conclusions are robust against stochasticity induced by finite population sizes. Our findings shed light on the importance of phenotypic heterogeneity in range expansions, paving the way to novel approaches to understand how biodiversity emerges and is maintained.Author summaryEcological populations are often exposed to unpredictable and variable environmental conditions. A number of strategies have evolved to cope with such uncertainty. One of them is stochastic phenotypic switching, by which some individuals in the community are enabled to tackle adverse conditions, even at the price of reducing overall growth in the short term. In this paper, we study the effectiveness of these “bet-hedging” strategies for a population in the process of colonizing new territory. We show that bet-hedging is more advantageous when the environment varies spatially rather than temporally, and infrequently rather than frequently.

scholarly journals A continuum of biological adaptations to environmental fluctuation

2019 ◽  
Vol 286 (1912) ◽  
pp. 20191623 ◽  
Author(s):  
Ming Liu ◽  
Dustin R. Rubenstein ◽  
Wei-Chung Liu ◽  
Sheng-Feng Shen
Keyword(s):  
Overlapping Generations ◽  
Bet Hedging ◽  
Environmental Fluctuation ◽  
Infinite Population ◽  
Biological Adaptation ◽  
Hedging Strategies ◽  
Wide Range ◽  
Population Sizes ◽  
Environmental Unpredictability ◽  
Per Capita

Bet-hedging—a strategy that reduces fitness variance at the expense of lower mean fitness among different generations—is thought to evolve as a biological adaptation to environmental unpredictability. Despite widespread use of the bet-hedging concept, most theoretical treatments have largely made unrealistic demographic assumptions, such as non-overlapping generations and fixed or infinite population sizes. Here, we extend the concept to consider overlapping generations by defining bet-hedging as a strategy with lower variance and mean per capita growth rate across different environments. We also define an opposing strategy—the rising-tide—that has higher mean but also higher variance in per capita growth. These alternative strategies lie along a continuum of biological adaptions to environmental fluctuation. Using stochastic Lotka–Volterra models to explore the evolution of the rising-tide versus bet-hedging strategies, we show that both the mean environmental conditions and the temporal scales of their fluctuations, as well as whether population dynamics are discrete or continuous, are crucial in shaping the type of strategy that evolves in fluctuating environments. Our model demonstrates that there are likely to be a wide range of ways that organisms with overlapping generations respond to environmental unpredictability beyond the classic bet-hedging concept.

scholarly journals Environmental variability and the evolution of bet-hedging strategies

2020 ◽  
Author(s):  
Kelley Slimon ◽  
Rachel M. Germain
Keyword(s):  
Environmental Variability ◽  
Dispersal Ability ◽  
Bet Hedging ◽  
Uncertain Environments ◽  
Climate Fluctuations ◽  
Heterogeneous Landscapes ◽  
Hedging Strategies ◽  
Biodiversity Maintenance ◽  
New Perspective ◽  
Offspring Generation

AbstractBet-hedging strategies, such as dispersal and dormancy, are predicted to evolve in varying and uncertain environments and are critical to ecological models of biodiversity maintenance. Theories of the specific ecological scenarios that favor the evolution of dispersal, dormancy, or their covariance are rarely tested, particularly for naturally-evolved populations that experience complex patterns of spatiotemporal environmental variation. We grew 23 populations of Vulpia microstachys, an annual grass native to California, in a greenhouse, and on the offspring generation measured seed dispersal ability and dormancy rates. We hypothesized that seed dormancy rates and dispersal abilities would be highest in populations from more productive, temporally variable sites, causing them to covary positively. Contrary to our hypothesis, our data suggest that both dispersal and dormancy evolve to combat different axes and scales of spatial heterogeneity, and are underlain by different seed traits, allowing them to evolve independently. Dormancy appears to have evolved as a strategy for overcoming microgeographic heterogeneity rather than temporal climate fluctuations, an outcome that to our knowledge has not been considered by theory. In sum, we provide much needed empirical data on the evolution of bet hedging, as well as a new perspective on the ecological function dormancy provides in heterogeneous landscapes.

Evaluating agricultural bet-hedging strategies in the Kona Field System: New high-precision230Th/U and14C dates and plant microfossil data from Kealakekua, Hawai‘i Island

2016 ◽  
Vol 52 (1) ◽  
pp. 70-80 ◽  
Author(s):  
MARK D. McCOY ◽  
MARA A. MULROONEY ◽  
MARK HORROCKS ◽  
HAI CHENG ◽  
THEGN N. LADEFOGED
Keyword(s):  
Bet Hedging ◽  
Field System ◽  
Hedging Strategies ◽  
Plant Microfossil

scholarly journals Seasonality and competition select for variable germination behavior in perennials

2022 ◽  
Author(s):  
Hanna ten Brink ◽  
Thomas Ray Haaland ◽  
Oystein Hjorthol Opedal
Keyword(s):  
Simulation Models ◽  
Population Variation ◽  
Priority Effects ◽  
Bet Hedging ◽  
Environmental Predictability ◽  
Hedging Strategies ◽  
Unpredictable Environments ◽  
Evolutionary Simulation ◽  
Negative Frequency Dependent Selection ◽  
Germination Timing

The common occurrence of within-population variation in germination behavior and associated traits such as seed size has long fascinated evolutionary ecologists. In annuals, unpredictable environments are known to select for bet-hedging strategies causing variation in dormancy duration and germination strategies. Variation in germination timing and associated traits is also commonly observed in perennials, and often tracks gradients of environmental predictability. Although bet-hedging is thought to occur less frequently in long-lived organisms, these observations suggest a role of bet-hedging strategies in perennials occupying unpredictable environments. We use complementary numerical and evolutionary simulation models of within- and among-individual variation in germination behavior in seasonal environments to show how bet-hedging interacts with density dependence, life-history traits, and priority effects due to competitive differences among germination strategies. We reveal substantial scope for bet-hedging to produce variation in germination behavior in long-lived plants, when "false starts" to the growing season results in either competitive advantages or increased mortality risk for alternative germination strategies. Additionally, we find that two distinct germination strategies can evolve and coexist through negative frequency-dependent selection. These models extend insights from bet-hedging theory to perennials and explore how competitive communities may be affected by ongoing changes in climate and seasonality patterns.

scholarly journals A New Approach to Predicting Cryptocurrency Returns Based on the Gold Prices with Support Vector Machines during the COVID-19 Pandemic Using Sensor-Related Data

Sensors ◽  
2021 ◽  
Vol 21 (18) ◽  
pp. 6319
Author(s):  
Esam Mahdi ◽  
Víctor Leiva ◽  
Saed Mara’Beh ◽  
Carlos Martin-Barreiro
Keyword(s):  
Investment Decisions ◽  
Trading Strategies ◽  
Support Vector ◽  
Uncertain Environments ◽  
New Approach ◽  
Adverse Conditions ◽  
Related Data ◽  
Svm Algorithm ◽  
Vector Machines ◽  
Real World Situation

In a real-world situation produced under COVID-19 scenarios, predicting cryptocurrency returns accurately can be challenging. Such a prediction may be helpful to the daily economic and financial market. Unlike forecasting the cryptocurrency returns, we propose a new approach to predict whether the return classification would be in the first, second, third quartile, or any quantile of the gold price the next day. In this paper, we employ the support vector machine (SVM) algorithm for exploring the predictability of financial returns for the six major digital currencies selected from the list of top ten cryptocurrencies based on data collected through sensors. These currencies are Binance Coin, Bitcoin, Cardano, Dogecoin, Ethereum, and Ripple. Our study considers the pre-COVID-19 and ongoing COVID-19 periods. An algorithm that allows updated data analysis, based on the use of a sensor in the database, is also proposed. The results show strong evidence that the SVM is a robust technique for devising profitable trading strategies and can provide accurate results before and during the current pandemic. Our findings may be helpful for different stakeholders in understanding the cryptocurrency dynamics and in making better investment decisions, especially under adverse conditions and during times of uncertain environments such as in the COVID-19 pandemic.

scholarly journals Ecological niche and bet-hedging strategies for Triodia (R.Br.) seed germination

2017 ◽  
Vol 121 (2) ◽  
pp. 367-375 ◽  
Author(s):  
Wolfgang Lewandrowski ◽  
Todd E Erickson ◽  
Emma L Dalziell ◽  
Jason C Stevens
Keyword(s):  
Seed Germination ◽  
Ecological Niche ◽  
Bet Hedging ◽  
Hedging Strategies

scholarly journals Modes of response to environmental change and the elusive empirical evidence for bet hedging

2011 ◽  
Vol 278 (1712) ◽  
pp. 1601-1609 ◽  
Author(s):  
Andrew M. Simons
Keyword(s):  
Environmental Change ◽  
Empirical Evidence ◽  
Natural Environments ◽  
Bet Hedging ◽  
Fluctuating Selection ◽  
Hedging Strategies ◽  
Evolutionary Response ◽  
Human Decision ◽  
Response To Environmental Change

Uncertainty is a problem not only in human decision-making, but is a prevalent quality of natural environments and thus requires evolutionary response. Unpredictable natural selection is expected to result in the evolution of bet-hedging strategies, which are adaptations to long-term fluctuating selection. Despite a recent surge of interest in bet hedging, its study remains mired in conceptual and practical difficulties, compounded by confusion over what constitutes evidence for its existence. Here, I attempt to resolve misunderstandings about bet hedging and its relationship with other modes of response to environmental change, identify the challenges inherent to its study and assess the state of existing empirical evidence. The variety and distribution of plausible bet-hedging traits found across 16 phyla in over 100 studies suggest their ubiquity. Thus, bet hedging should be considered a specific mode of response to environmental change. However, the distribution of bet-hedging studies across evidence categories—defined according to potential strength—is heavily skewed towards weaker categories, underscoring the need for direct appraisals of the adaptive significance of putative bet-hedging traits in nature.

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