scholarly journals Host-parasite coevolution can promote the evolution of seed banking as a bet-hedging strategy

2018 ◽  
Author(s):  
Mélissa Verin ◽  
Aurélien Tellier
Keyword(s):  
Genetic Linkage ◽  
Bet Hedging ◽  
Gene Model ◽  
Hedging Strategy ◽  
Resistant Genotype ◽  
Additional Hypothesis ◽  
Delayed Emergence ◽  
Environmental Unpredictability ◽  
Banking Strategy ◽  
Host Parasite

AbstractSeed (egg) banking is a common bet-hedging strategy maximizing the fitness of organisms facing environmental unpredictability by the delayed emergence of offspring. Yet, this condition often requires fast and drastic stochastic shifts between good and bad years. We hypothesize that the host seed banking strategy can evolve in response to coevolution with parasites because the coevolutionary cycles promote a gradually changing environment over longer times than seed persistence. We study the evolution of host germination fraction as a quantitative trait using both pairwise competition and multiple mutant competition methods, while the germination locus can be genetically linked or unlinked with the host locus under coevolution. In a gene-for-gene model of coevolution, hosts evolve a seed bank strategy under unstable coevolutionary cycles promoted by moderate to high costs of resistance or strong disease severity. Moreover, when assuming genetic linkage between coevolving and germination loci, the resistant genotype always evolves seed banking in contrast to susceptible hosts. Under a matching-allele interaction, both hosts’ genotypes exhibit the same seed banking strategy irrespective of the genetic linkage between loci. We suggest host-parasite coevolution as an additional hypothesis for the evolution of seed banking as a temporal bet-hedging strategy.

scholarly journals Biological adaptation under fluctuating selection

2018 ◽  
Author(s):  
Ming Liu ◽  
Dustin R. Rubenstein ◽  
Wei-Chung Liu ◽  
Sheng-Feng Shen
Keyword(s):  
Evolutionary Strategy ◽  
Bet Hedging ◽  
Negative Effects ◽  
Fluctuating Selection ◽  
Hedging Strategy ◽  
Biological Adaptation ◽  
Wide Range ◽  
Population Sizes ◽  
Mean And Variance ◽  
Environmental Unpredictability

AbstractBet-hedging—an evolutionary strategy that reduces fitness variance at the expense of lower mean fitness—is the primary explanation for most forms of biological adaptation to environmental unpredictability. However, most applications of bet-hedging theory to biological problems have largely made unrealistic demographic assumptions, such as non-overlapping generations and fixed population sizes. Consequently, the generality and applicability of bet-hedging theory to real world phenomena remains unclear. Here we use continuous-time, stochastic Lotka-Volterra models to relax overly restrictive demographic assumptions and explore a suite of biological adaptations to fluctuating environments. We discover a novel “rising-tide strategy” that—unlike the bet-hedging strategy—generates both a higher mean and variance in fitness. The positive fitness effects of the rising-tide strategy’s specialization to good years can overcome any negative effects of higher fitness variance in unpredictable environments. Moreover, we show not only that the rising-tide strategy will be selected for over a much broader range of environmental conditions than the bet-hedging strategy, but also under more realistic demographic circumstances. Ultimately, our model demonstrates that there are likely to be a wide range of ways that organisms respond to environmental unpredictability.

scholarly journals Host-parasite coevolution can promote the evolution of seed banking as a bet-hedging strategy

Evolution ◽  
2018 ◽  
Vol 72 (7) ◽  
pp. 1362-1372 ◽  
Author(s):  
Mélissa Verin ◽  
Aurélien Tellier
Keyword(s):  
Bet Hedging ◽  
Hedging Strategy ◽  
Host Parasite

scholarly journals Individual reversible plasticity as a genotype‐level bet‐hedging strategy

2021 ◽  
Author(s):  
Thomas R. Haaland ◽  
Jonathan Wright ◽  
Irja I. Ratikainen
Keyword(s):  
Bet Hedging ◽  
Hedging Strategy

Cleistogamy as a bet‐hedging strategy in Oxalis acetosella , a perennial herb

1998 ◽  
Vol 86 (3) ◽  
pp. 491-500 ◽  
Author(s):  
Henrik Berg ◽  
Peter Redbo‐torstensson
Keyword(s):  
Perennial Herb ◽  
Bet Hedging ◽  
Hedging Strategy ◽  
Oxalis Acetosella

scholarly journals Different resource allocation in a Bacillus subtilis population displaying bimodal motility

2021 ◽  
Author(s):  
Simon Syvertsson ◽  
Biwen Wang ◽  
Jojet Staal ◽  
Yongqiang Gao ◽  
Remco Kort ◽  
...  
Keyword(s):  
Gene Expression ◽  
Bacillus Subtilis ◽  
Exponential Growth ◽  
Environmental Changes ◽  
Feedback Regulation ◽  
Bet Hedging ◽  
Hedging Strategy ◽  
Negative Feedback Regulation ◽  
Continuous Increase ◽  
Motile Cells

To cope with sudden changes in their environment, bacteria can use a bet-hedging strategy by dividing the population into cells with different properties. This so-called bimodal or bistable cellular differentiation is generally controlled by positive feedback regulation of transcriptional activators. Due to the continuous increase in cell volume, it is difficult for these activators to reach an activation threshold concentration when cells are growing exponentially. This is one reason why bimodal differentiation is primarily observed from the onset of the stationary phase when exponential growth ceases. An exception is the bimodal induction of motility in Bacillus subtilis, which occurs early during exponential growth. Several mechanisms have been put forward to explain this, including double negative-feedback regulation and the stability of the mRNA molecules involved. In this study, we used fluorescence-assisted cell sorting to compare the transcriptome of motile and non-motile cells and noted that expression of ribosomal genes is lower in motile cells. This was confirmed using an unstable GFP reporter fused to the strong ribosomal rpsD promoter. We propose that the reduction in ribosomal gene expression in motile cells is the result of a diversion of cellular resources to the synthesis of the chemotaxis and motility systems. In agreement, single-cell microscopic analysis showed that motile cells are slightly shorter than non-motile cells, an indication of slower growth. We speculate that this growth rate reduction can contribute to the bimodal induction of motility during exponential growth. IMPORTANCE To cope with sudden environmental changes, bacteria can use a bet-hedging strategy and generate different types of cells within a population, so called bimodal differentiation. For example, a Bacillus subtilis culture can contain both motile and non-motile cells. In this study we compared the gene expression between motile and non-motile cells. It appeared that motile cells express less ribosomes. To confirm this, we constructed a ribosomal promoter fusion that enabled us to measure expression of this promoter in individual cells. This reporter fusion confirmed our initial finding. The re-allocation of cellular resources from ribosome synthesis towards synthesis of the motility apparatus results in a reduction in growth. Interestingly, this growth reduction has been shown to stimulate bimodal differentiation.

A bet-hedging strategy rather than just a classic fast life-history strategy exhibited by invasive fall armyworm

2021 ◽  
Author(s):  
Pengxiang Wu ◽  
Qilin Ren ◽  
Wei Wang ◽  
Zhuo Ma ◽  
Runzhi Zhang
Keyword(s):  
Life History ◽  
Life History Strategy ◽  
Fall Armyworm ◽  
Bet Hedging ◽  
Hedging Strategy

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 Costs and benefits of maternally inherited algal symbionts in coral larvae

2017 ◽  
Vol 284 (1857) ◽  
pp. 20170852 ◽  
Author(s):  
Valérie F. Chamberland ◽  
Kelly R. W. Latijnhouwers ◽  
Jef Huisman ◽  
Aaron C. Hartmann ◽  
Mark J. A. Vermeij
Keyword(s):  
Marine Invertebrates ◽  
Costs And Benefits ◽  
Bet Hedging ◽  
Hedging Strategy ◽  
Coral Larvae ◽  
Stony Coral ◽  
Algal Symbionts ◽  
Settlement Success ◽  
Spatio Temporal ◽  
Endosymbiotic Algae

Many marine invertebrates provide their offspring with symbionts. Yet the consequences of maternally inherited symbionts on larval fitness remain largely unexplored. In the stony coral Favia fragum (Esper 1797), mothers produce larvae with highly variable amounts of endosymbiotic algae, and we examined the implications of this variation in symbiont density on the performance of F. fragum larvae under different environmental scenarios. High symbiont densities prolonged the period that larvae actively swam and searched for suitable settlement habitats. Thermal stress reduced survival and settlement success in F. fragum larvae, whereby larvae with high symbiont densities suffered more from non-lethal stress and were five times more likely to die compared with larvae with low symbiont densities. These results show that maternally inherited algal symbionts can be either beneficial or harmful to coral larvae depending on the environmental conditions at hand, and suggest that F. fragum mothers use a bet-hedging strategy to minimize risks associated with spatio-temporal variability in their offspring's environment.

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