scholarly journals Attracting pollinators vs escaping herbivores: eco-evolutionary dynamics of plants confronted with an ecological trade-off

2021 ◽  
Author(s):  
Youssef Yacine ◽  
Nicolas Loeuille
Keyword(s):  
Evolutionary Dynamics ◽  
Plant Traits ◽  
Adaptive Dynamics ◽  
Disruptive Selection ◽  
Stabilizing Selection ◽  
Ecological Communities ◽  
Trade Off ◽  
Trade Offs ◽  
Herbivore Community ◽  
Plant Animal Interactions

AbstractA large number of plant traits are subject to an ecological trade-off between attracting pollinators and escaping herbivores. The interplay of both plant-animal interactions determines their evolution. Within a plant-pollinator-herbivore community in which interaction strengths depend on trait-matching, eco-evolutionary dynamics are studied using the framework of adaptive dynamics. We characterize the type of selection acting on the plant phenotype and the consequences for multispecies coexistence. We find that pollination favors stabilizing selection and coexistence. In contrast, herbivory fosters runaway selection, which threatens plant-animal coexistence. These contrasting dynamics highlight the key role of ecological trade-offs in structuring ecological communities. In particular, we show that disruptive selection is possible when such trade-offs are strong. While the interplay of pollination and herbivory is known to maintain plant polymorphism in several cases, our work suggests that it might also have fueled the diversification process itself.

scholarly journals Evolution of nutrient acquisition: when adaptation fills the gap between contrasting ecological theories

2010 ◽  
Vol 278 (1704) ◽  
pp. 449-457 ◽  
Author(s):  
S. Boudsocq ◽  
S. Barot ◽  
N. Loeuille
Keyword(s):  
Evolutionary Dynamics ◽  
Plant Biomass ◽  
Adaptive Dynamics ◽  
Ecosystem Model ◽  
Point Of View ◽  
Mineral Nutrient ◽  
Trade Off ◽  
Ecosystem Properties ◽  
Ecological Theories ◽  
Limiting Nutrient

Although plant strategies for acquiring nutrients have been widely studied from a functional point of view, their evolution is still not well understood. In this study, we investigate the evolutionary dynamics of these strategies and determine how they influence ecosystem properties. To do so, we use a simple nutrient-limited ecosystem model in which plant ability to take up nutrients is subject to adaptive dynamics. We postulate the existence of a trade-off between this ability and mortality. We show that contrasting strategies are possible as evolutionary outcomes, depending on the shape of the trade-off and, when nitrogen is considered as the limiting nutrient, on the intensity of symbiotic fixation. Our model enables us to bridge these evolutionary outcomes to classical ecological theories such as Hardin's tragedy of the commons and Tilman's rule of R *. Evolution does not systematically maximize plant biomass or primary productivity. On the other hand, each evolutionary outcome leads to a decrease in the availability of the limiting mineral nutrient, supporting the work of Tilman on competition between plants for a single resource. Our model shows that evolution can be used to link different classical ecological results and that adaptation may influence ecosystem properties in contrasted ways.

Classifying the role of trade-offs in the evolutionary diversity of pathogens

2005 ◽  
Vol 462 (2065) ◽  
pp. 97-116 ◽  
Author(s):  
Ivana Gudelj ◽  
Ciprian D Coman ◽  
Robert E Beardmore
Keyword(s):  
Phenotypic Diversity ◽  
Transmission Rate ◽  
Adaptive Dynamics ◽  
Reaction Diffusion ◽  
Pathogen Transmission ◽  
Reaction Diffusion Equations ◽  
Central Feature ◽  
Pathogen Population ◽  
Trade Off ◽  
Trade Offs

In this paper we use a system of non-local reaction–diffusion equations to study the effect of host heterogeneity on the phenotypic evolution of a pathogen population. The evolving phenotype is taken to be the transmission rate of the pathogen on the different hosts, and in our system there are two host populations present. The central feature of our model is a trade-off relationship between the transmission rates on these hosts, which means that an increase in the pathogen transmission on one host will lead to a decrease in the pathogen transmission on the other. The purpose of the paper is to develop a classification of phenotypic diversity as a function of the shape of the trade-off relationship and this is achieved by determining the maximum number of phenotypes a pathogen population can support in the long term, for a given form of the trade-off. Our findings are then compared with results obtained by applying classical theory from evolutionary ecology and the more recent adaptive dynamics method to the same host–pathogen system. We find our work to be in good agreement with these two approaches.

scholarly journals Implications of the evolution of agriculture and resource foraging for the maintenance of species diversity and community structure

2021 ◽  
Author(s):  
Aurore Picot ◽  
Thibaud Monnin ◽  
Nicolas Loeuille
Keyword(s):  
Community Structure ◽  
Opportunity Cost ◽  
Evolutionary Dynamics ◽  
Niche Construction ◽  
Adaptive Dynamics ◽  
Trade Off ◽  
Selective Pressures ◽  
Negative Effect ◽  
The Cost ◽  
Positive Effect

AbstractAgriculture - cultivation of plants, algae, fungi and animal herding - is found in numerous taxa such as humans, but also ants, beetles, fishes and even bacteria. Such niche construction behaviours have evolved independently from hunter/predation behaviours, though many species remain primarily predators. We here investigate when such a transition from predation/hunter behaviour to agriculture is favoured. In these systems where a consumer has a positive effect on its resource, we can expect an allocative cost of agriculture for the farmer, hence modifying the selective pressures acting upon it. The management of the resource may have a negative effect on its consumption: for instance, when the consumer defends the resource against other predators (exploitation cost). In other situations, the cost may occur on the foraging of alternative resources, for instance if the consumer spends more time nearby the farmed resource (opportunity cost). Here, we develop a simple three-species model constituted by a farmer species that consumes two resource species, one of them receiving an additional positive effect from the consumer. We consider two trade-off scenarios based on how the cost of agriculture is implemented, either as an exploitation cost or as an opportunity cost. We use an adaptive dynamics approach to study the conditions for the evolution of the investment into agriculture and specialization on the two resources, and consequences on the ecological dynamics of the community. Eco-evolutionary dynamics generate a feedback between the evolution of agriculture and specialization on the helped resource, that can lead to varying selected intensity of agriculture, from generalist strategies with no agriculture, to farmer phenotypes that are entirely specialized on the farmed resource, with possible coexistence between those two extreme strategies.

scholarly journals Plant eco-evolution weakens mutualistic interaction with declining pollinator populations

2019 ◽  
Author(s):  
Avril Weinbach ◽  
Nicolas Loeuille ◽  
Rudolf P. Rohr
Keyword(s):  
Growth Rates ◽  
Evolutionary Dynamics ◽  
Plant Evolution ◽  
Population Declines ◽  
Pollination Services ◽  
Nectar Production ◽  
Trade Off ◽  
Trade Offs ◽  
Mutualistic Interaction ◽  
Plant Pollinator

AbstractRecent pollinator population declines threaten pollination services and greatly impact plant-pollinator coevolution. We investigate how such evolutionary effects affect plant-pollinator coexistence. Using eco-evolutionary dynamics, we study the evolution of plant attractiveness in a simple pollinator-plant model, assuming an allocation trade-off between attractiveness (e.g. nectar production, flower shape and size) and plant intrinsic growth rates. First, we investigated how attractiveness evolution changes species persistence, biomass production, and the intensity of the mutualism (as a proxy for pollination services). We show that the shape of the allocation trade-off is key in determining the outcome of the eco-evolutionary dynamics and that concave trade-offs allow convergence to stable plant-pollinator coexistence. Then we analyse the effect of pollinator population declines on the eco-evolutionary dynamics. Decreasing intrinsic growth rates of pollinator population results in a plant-evolution driven disappearance of the mutualistic interaction, eventually leading to pollinator extinction. With asymmetric mutualism favouring the pollinator, the evolutionary disappearance of the mutualistic interaction is delayed. Our results suggest that evolution may account for the current collapse of pollination systems and that restoration attempts should be enforced early enough to prevent potential negative effects driven by plant evolution.

scholarly journals Treating symptomatic infections and the co-evolution of virulence and drug resistance

2020 ◽  
Author(s):  
Samuel Alizon
Keyword(s):  
Evolutionary Dynamics ◽  
Adaptive Dynamics ◽  
Drug Resistant ◽  
Treatment Rate ◽  
Virulence Evolution ◽  
Trade Offs ◽  
Virulent Strains ◽  
Host Mortality ◽  
Parameter Values

AbstractAntimicrobial therapeutic treatments are by definition applied after the onset of symptoms, which tend to correlate with infection severity. Using mathematical epidemiology models, I explore how this link affects the coevolutionary dynamics between the virulence of an infection, measured via host mortality rate, and its susceptibility to chemotherapy. I show that unless resistance pre-exists in the population, drug-resistant infections are initially more virulent than drug-sensitive ones. As the epidemic unfolds, virulence is more counter-selected in drug-sensitive than in drug-resistant infections. This difference decreases over time and, eventually, the exact shape of genetic trade-offs govern long-term evolutionary dynamics. Using adaptive dynamics, I show that two types of evolutionary stable strategies (ESS) may be reached in the context of this simple model and that, depending on the parameter values, an ESS may only be locally stable. In general, the more the treatment rate increases with virulence, the lower the ESS value. Overall, both on the short-term and long-term, having treatment rate depend on infection virulence tend to favour less virulent strains in drug-sensitive infections. These results highlight the importance of the feedbacks between epidemiology, public health policies and parasite evolution, and have implications for the monitoring of virulence evolution.

scholarly journals Rapid evolution of learning and reproduction in natural populations of Drosophila melanogaster

2018 ◽  
Author(s):  
Emily L. Behrman ◽  
Tadeusz J. Kawecki ◽  
Paul Schmidt
Keyword(s):  
Drosophila Melanogaster ◽  
Evolutionary Dynamics ◽  
Rna Binding ◽  
Rapid Evolution ◽  
Learning Ability ◽  
Learning Performance ◽  
General Mechanism ◽  
Behavioural Plasticity ◽  
Trade Off ◽  
Trade Offs

AbstractLearning is a general mechanism of adaptive behavioural plasticity whose benefits and costs depend on the environment. Thus, seasonal oscillations in temperate environments between winter and summer might produce cyclical selection pressures that would drive rapid evolution of learning performance in multivoltine populations. To test this hypothesis, we investigated the evolutionary dynamics of learning ability over this rapid seasonal timescale in a natural population of Drosophila melanogaster. Associative learning was tested in common garden-raised flies collected from nature in the spring and fall over three consecutive years. The spring flies consistently learned better than fall flies, revealing seasonal evolution of improved learning performance in nature. Fecundity showed the opposite seasonal pattern, suggesting a trade-off between learning and reproduction. This trade-off also held within population: more fecund individual females learned less well. This trade-off is mediated at least in part by natural polymorphism in the RNA binding protein couch potato (cpo), with a genotype favoured during summer showing poorer learning performance and higher fecundity than a genotype favoured over winter. Thus, seasonal environments can drive rapid cyclical evolution of learning performance, but the evolutionary dynamics may be driven by trade-offs generated by pleiotropic effects of causative alleles selected for other reasons.

Dual Goals for Speed and Accuracy on the Same Performance Task

2012 ◽  
Vol 11 (3) ◽  
pp. 118-126 ◽  
Author(s):  
Olive Emil Wetter ◽  
Jürgen Wegge ◽  
Klaus Jonas ◽  
Klaus-Helmut Schmidt
Keyword(s):  
Memory Scanning ◽  
Performance Task ◽  
Performance Tasks ◽  
Trade Off ◽  
Test Experiment ◽  
Trade Offs ◽  
New Finding ◽  
Sternberg Paradigm ◽  
Speed Accuracy ◽  
Speed And Accuracy

In most work contexts, several performance goals coexist, and conflicts between them and trade-offs can occur. Our paper is the first to contrast a dual goal for speed and accuracy with a single goal for speed on the same task. The Sternberg paradigm (Experiment 1, n = 57) and the d2 test (Experiment 2, n = 19) were used as performance tasks. Speed measures and errors revealed in both experiments that dual as well as single goals increase performance by enhancing memory scanning. However, the single speed goal triggered a speed-accuracy trade-off, favoring speed over accuracy, whereas this was not the case with the dual goal. In difficult trials, dual goals slowed down scanning processes again so that errors could be prevented. This new finding is particularly relevant for security domains, where both aspects have to be managed simultaneously.

The Effects of Decision Time on Perceptions of Decisions and Decision Makers in (Moral) Trade-Off Scenarios

2019 ◽  
Author(s):  
Anna Katharina Spälti ◽  
Mark John Brandt ◽  
Marcel Zeelenberg
Keyword(s):  
Decision Process ◽  
Decision Time ◽  
Decision Makers ◽  
Process Information ◽  
Total N ◽  
Trade Off ◽  
Financial Gain ◽  
Trade Offs ◽  
Sacred Values ◽  
Moral Context

People often have to make trade-offs. We study three types of trade-offs: 1) "secular trade-offs" where no moral or sacred values are at stake, 2) "taboo trade-offs" where sacred values are pitted against financial gain, and 3) "tragic trade-offs" where sacred values are pitted against other sacred values. Previous research (Critcher et al., 2011; Tetlock et al., 2000) demonstrated that tragic and taboo trade-offs are not only evaluated by their outcomes, but are also evaluated based on the time it took to make the choice. We investigate two outstanding questions: 1) whether the effect of decision time differs for evaluations of decisions compared to decision makers and 2) whether moral contexts are unique in their ability to influence character evaluations through decision process information. In two experiments (total N = 1434) we find that decision time affects character evaluations, but not evaluations of the decision itself. There were no significant differences between tragic trade-offs and secular trade-offs, suggesting that the decisions structure may be more important in evaluations than moral context. Additionally, the magnitude of the effect of decision time shows us that decision time, may be of less practical use than expected. We thus urge, to take a closer examination of the processes underlying decision time and its perception.

Predicting Undesired Treatment Outcome in Mental Healthcare: Machine Learning Study (Preprint)

2019 ◽  
Author(s):  
Kasper Van Mens ◽  
Joran Lokkerbol ◽  
Richard Janssen ◽  
Robert de Lange ◽  
Bea Tiemens
Keyword(s):  
Machine Learning ◽  
Treatment Outcome ◽  
Mental Health Treatment ◽  
Mental Healthcare ◽  
Machine Learning Algorithms ◽  
Gradient Boosting ◽  
Trade Off ◽  
Trade Offs ◽  
Outcome Monitoring ◽  
Extreme Gradient Boosting

BACKGROUND It remains a challenge to predict which treatment will work for which patient in mental healthcare. OBJECTIVE In this study we compare machine algorithms to predict during treatment which patients will not benefit from brief mental health treatment and present trade-offs that must be considered before an algorithm can be used in clinical practice. METHODS Using an anonymized dataset containing routine outcome monitoring data from a mental healthcare organization in the Netherlands (n = 2,655), we applied three machine learning algorithms to predict treatment outcome. The algorithms were internally validated with cross-validation on a training sample (n = 1,860) and externally validated on an unseen test sample (n = 795). RESULTS The performance of the three algorithms did not significantly differ on the test set. With a default classification cut-off at 0.5 predicted probability, the extreme gradient boosting algorithm showed the highest positive predictive value (ppv) of 0.71(0.61 – 0.77) with a sensitivity of 0.35 (0.29 – 0.41) and area under the curve of 0.78. A trade-off can be made between ppv and sensitivity by choosing different cut-off probabilities. With a cut-off at 0.63, the ppv increased to 0.87 and the sensitivity dropped to 0.17. With a cut-off of at 0.38, the ppv decreased to 0.61 and the sensitivity increased to 0.57. CONCLUSIONS Machine learning can be used to predict treatment outcomes based on routine monitoring data.This allows practitioners to choose their own trade-off between being selective and more certain versus inclusive and less certain.

Challenges in the Empirical Study of Global Governance Legitimacy

2018 ◽  
Author(s):  
Steven Bernstein
Keyword(s):  
Empirical Study ◽  
Global Governance ◽  
Research Agenda ◽  
Cultural Factors ◽  
Theory Building ◽  
Trade Off ◽  
Trade Offs ◽  
Different Types ◽  
Political Communities

This commentary discusses three challenges for the promising and ambitious research agenda outlined in the volume. First, it interrogates the volume’s attempts to differentiate political communities of legitimation, which may vary widely in composition, power, and relevance across institutions and geographies, with important implications not only for who matters, but also for what gets legitimated, and with what consequences. Second, it examines avenues to overcome possible trade-offs from gains in empirical tractability achieved through the volume’s focus on actor beliefs and strategies. One such trade-off is less attention to evolving norms and cultural factors that may underpin actors’ expectations about what legitimacy requires. Third, it addresses the challenge of theory building that can link legitimacy sources, (de)legitimation practices, audiences, and consequences of legitimacy across different types of institutions.

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