scholarly journals Evolution of a predator-induced, nonlinear reaction norm

2017 ◽  
Vol 284 (1861) ◽  
pp. 20170859 ◽  
Author(s):  
Mauricio J. Carter ◽  
Martin I. Lind ◽  
Stuart R. Dennis ◽  
William Hentley ◽  
Andrew P. Beckerman
Keyword(s):  
Evolutionary Dynamics ◽  
Daphnia Pulex ◽  
Reaction Norm ◽  
Maximum Response ◽  
Selective Predation ◽  
Evolutionary Trajectory ◽  
Defensive Reaction ◽  
Selection Gradients ◽  
Hunting Strategies ◽  
Evolutionary Response

Inducible, anti-predator traits are a classic example of phenotypic plasticity. Their evolutionary dynamics depend on their genetic basis, the historical pattern of predation risk that populations have experienced and current selection gradients. When populations experience predators with contrasting hunting strategies and size preferences, theory suggests contrasting micro-evolutionary responses to selection. Daphnia pulex is an ideal species to explore the micro-evolutionary response of anti-predator traits because they face heterogeneous predation regimes, sometimes experiencing only invertebrate midge predators and other times experiencing vertebrate fish and invertebrate midge predators. We explored plausible patterns of adaptive evolution of a predator-induced morphological reaction norm. We combined estimates of selection gradients that characterize the various habitats that D. pulex experiences with detail on the quantitative genetic architecture of inducible morphological defences. Our data reveal a fine scale description of daphnid defensive reaction norms, and a strong covariance between the sensitivity to cues and the maximum response to cues. By analysing the response of the reaction norm to plausible, predator-specific selection gradients, we show how in the context of this covariance, micro-evolution may be more uniform than predicted from size-selective predation theory. Our results show how covariance between the sensitivity to cues and the maximum response to cues for morphological defence can shape the evolutionary trajectory of predator-induced defences in D. pulex .

scholarly journals Swift evolutionary response of microbes to a rise in anthropogenic mercury in the Northern Hemisphere

2019 ◽  
Vol 14 (3) ◽  
pp. 788-800 ◽  
Author(s):  
Matti O. Ruuskanen ◽  
Stéphane Aris-Brosou ◽  
Alexandre J. Poulain
Keyword(s):  
Northern Hemisphere ◽  
Industrial Revolution ◽  
Evolutionary Dynamics ◽  
Atmospheric Mercury ◽  
Molecular Clocks ◽  
Mercury Deposition ◽  
Dna Encoding ◽  
Effective Population ◽  
Evolutionary Trajectory ◽  
Evolutionary Response

AbstractAnthropogenic mercury remobilization has considerably increased since the Industrial Revolution in the late 1700s. The Minamata Convention on Mercury is a United Nations treaty (2017) aiming at curbing mercury emissions. Unfortunately, evaluating the effectiveness of such a global treaty is hampered by our inability to determine the lag in aquatic ecosystem responses to a change in atmospheric mercury deposition. Whereas past metal concentrations are obtained from core samples, there are currently no means of tracking historical metal bioavailability or toxicity. Here, we recovered DNA from nine dated sediment cores collected in Canada and Finland, and reconstructed the past demographics of microbes carrying genes coding for the mercuric reductase (MerA)—an enzyme involved in Hg detoxification—using Bayesian relaxed molecular clocks. We found that the evolutionary dynamics of merA exhibited a dramatic increase in effective population size starting from 1783.8 ± 3.9 CE, which coincides with both the Industrial Revolution, and with independent measurements of atmospheric Hg concentrations. We show that even low levels of anthropogenic mercury affected the evolutionary trajectory of microbes in the Northern Hemisphere, and that microbial DNA encoding for detoxification determinants stored in environmental archives can be used to track historical pollutant toxicity.

scholarly journals Loci, genes, and gene networks associated with life history variation in a model ecological organism,Daphnia pulex(complex)

2018 ◽  
Author(s):  
Jacob W. Malcom ◽  
Thomas E. Juenger ◽  
Mathew A. Leibold
Keyword(s):  
Gene Expression ◽  
Genetic Variation ◽  
Life History ◽  
Molecular Basis ◽  
Life History Traits ◽  
Evolutionary Dynamics ◽  
Daphnia Pulex ◽  
Life History Trait ◽  
Life History Variation ◽  
Trait Variation

ABSTRACTBackgroundIdentifying the molecular basis of heritable variation provides insight into the underlying mechanisms generating phenotypic variation and the evolutionary history of organismal traits. Life history trait variation is of central importance to ecological and evolutionary dynamics, and contemporary genomic tools permit studies of the basis of this variation in non-genetic model organisms. We used high density genotyping, RNA-Seq gene expression assays, and detailed phenotyping of fourteen ecologically important life history traits in a wild-caught panel of 32Daphnia pulexclones to explore the molecular basis of trait variation in a model ecological species.ResultsWe found extensive phenotypic and a range of heritable genetic variation (~0 < H2< 0.44) in the panel, and accordingly identify 75-261 genes—organized in 3-6 coexpression modules—associated with genetic variation in each trait. The trait-related coexpression modules possess well-supported promoter motifs, and in conjunction with marker variation at trans- loci, suggest a relatively small number of important expression regulators. We further identify a candidate genetic network with SNPs in eight known transcriptional regulators, and dozens of differentially expressed genes, associated with life history variation. The gene-trait associations include numerous un-annotated genes, but also support several a priori hypotheses, including an ecdysone-induced protein and several Gene Ontology pathways.ConclusionThe genetic and gene expression architecture ofDaphnialife history traits is complex, and our results provide numerous candidate loci, genes, and coexpression modules to be tested as the molecular mechanisms that underlieDaphniaeco-evolutionary dynamics.

scholarly journals Eco-evolutionary dynamics: disentangling phenotypic, environmental and population fluctuations

2009 ◽  
Vol 364 (1523) ◽  
pp. 1491-1498 ◽  
Author(s):  
Thomas H.G. Ezard ◽  
Steeve D. Côté ◽  
Fanie Pelletier
Keyword(s):  
Population Growth ◽  
Evolutionary Dynamics ◽  
Environmental Variability ◽  
Phenotypic Variability ◽  
Ecological Change ◽  
Population Fluctuations ◽  
Rapid Responses ◽  
Evolutionary Response ◽  
Anthropogenic Threats ◽  
The Impact

Decomposing variation in population growth into contributions from both ecological and evolutionary processes is of fundamental concern, particularly in a world characterized by rapid responses to anthropogenic threats. Although the impact of ecological change on evolutionary response has long been acknowledged, the converse has predominantly been neglected, especially empirically. By applying a recently published conceptual framework, we assess and contrast the relative importance of phenotypic and environmental variability on annual population growth in five ungulate populations. In four of the five populations, the contribution of phenotypic variability was greater than the contribution of environmental variability, although not significantly so. The similarity in the contributions of environment and phenotype suggests that neither is worthy of neglect. Population growth is a consequence of multiple processes, which strengthens arguments advocating integrated approaches to assess how populations respond to their environments.

scholarly journals Polygenic variation in sexual investment across an ephemerality gradient in Daphnia pulex

2021 ◽  
Author(s):  
Karen B Barnard-Kubow ◽  
Dörthe Becker ◽  
Connor S Murray ◽  
Robert Porter ◽  
Grace Gutierrez ◽  
...  
Keyword(s):  
Reproductive Strategy ◽  
Evolutionary Dynamics ◽  
Daphnia Pulex ◽  
Clonal Diversity ◽  
Basic Question ◽  
Male Production ◽  
Dynamic Nature ◽  
Quantitative Genetic ◽  
History Of ◽  
Polygenic Variation

Species across the tree of life can switch between asexual and sexual reproduction. In facultatively sexual species, the ability to switch between reproductive modes is often environmentally dependent and subject to local adaptation. However, the ecological and evolutionary factors that influence the maintenance and turnover of polymorphism associated with facultative sex remain unclear. To address this basic question, we studied the ecological and evolutionary dynamics of polymorphism in reproductive strategy in a metapopulation of the model facultative sexual, Daphnia pulex, located in the southern United Kingdom. We found that patterns of clonal diversity, but not genetic diversity varied with ephemerality. Reconstruction of a multi-year pedigree demonstrated the co-existence of clones that were found to differ in their investment into male production. Mapping of quantitative variation in male production using lab-generated and field-collected individuals identified multiple putative QTL underlying this trait, and we identified a plausible candidate gene. The evolutionary history of these QTL suggests that they are relatively young, and male limitation in this system is a rapidly evolving trait. Our work highlights the dynamic nature of the genetic structure and composition of facultative sex across space and time and suggests that quantitative genetic variation in reproductive strategy can undergo rapid evolutionary turnover.

scholarly journals Eco-evolutionary partitioning metrics: a practical guide for biologists

2018 ◽  
Vol 148 (2) ◽  
Author(s):  
Lynn Govaert
Keyword(s):  
Time Scales ◽  
Evolutionary Dynamics ◽  
Detailed Comparison ◽  
Reaction Norm ◽  
Evolutionary Change ◽  
Evolutionary Processes ◽  
Similar Time ◽  
Practical Guide ◽  
Relative Contribution ◽  
Community Data

It is well-known that ecological and evolutionary processes can occur on similar time scales resulting in eco-evolutionary dynamics. One of the main questions in eco-evolutionary dynamics involves the assessment of the relative contribution of evolution, ecology and their interaction in the eco-evolutionary change under study. This has led to the development of several methods aimed to quantify the contributions of ecology and evolution to observed trait change, here referred to as eco-evolutionary partitioning metrics. This study provides an overview on currently-used partitioning metrics with a focus on methods that can quantify evolutionary and non-evolutionary contributions to population and community trait change. I highlight key differences between these metrics found in previous studies. Additionally, I also provide a detailed comparison between the ‘Geber’ method and the reaction norm approach. Next, I provide a guideline for researchers to assess which metrics are best suited for their data, give an overview on the type of data needed for these metrics, and how this data can be collected with a focus on community data.

scholarly journals No evidence for short-term evolutionary response to a warming environment in Drosophila

2021 ◽  
Author(s):  
Marta A. Santos ◽  
Ana Carromeu-Santos ◽  
Ana S. Quina ◽  
Mauro Santos ◽  
Margarida Matos ◽  
...  
Keyword(s):  
Thermal Response ◽  
Reaction Norm ◽  
Thermal Reaction ◽  
Historical Background ◽  
Adaptive Responses ◽  
Short Term ◽  
Warming Scenario ◽  
Evolutionary Response ◽  
Evolution Experiment ◽  
Global Warming Scenario

AbstractAdaptive evolution is key in mediating responses to climate change. Such evolution will expectedly lead to changes in the populations’ thermal reaction norm and improve their ability to cope with stressful conditions. Conversely, constraints of different nature might limit the adaptive response. Here, we test these expectations by performing a real-time evolution experiment in historically differentiated Drosophila subobscura populations. We address the phenotypic changes of flies evolving for nine generations in a daily fluctuating environment with average constant temperature, or a warming environment with increasing average and amplitude temperature across generations. Our results showed that (1) evolution under a global warming scenario has not led, so far, to a noticeable change in the thermal response; (2) historical background appears to be affecting the responses of populations under the warming environment, particularly at higher temperatures; (3) thermal reaction norms are trait-dependent: while lifelong exposure to low temperature decreases fecundity and productivity but not viability, high temperature causes negative transgenerational effects on productivity and viability, even though fecundity remains high. These findings raise concerns about the short-term efficiency of adaptive responses to the current changing climate.

scholarly journals Steering ecological-evolutionary dynamics to improve artificial selection of microbial communities

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Li Xie ◽  
Wenying Shou
Keyword(s):  
Microbial Communities ◽  
Artificial Selection ◽  
Species Interactions ◽  
Evolutionary Dynamics ◽  
Species Coexistence ◽  
Evolutionary Trajectory ◽  
Community Function ◽  
Link Type ◽  
Selection Strategies ◽  
Effective Selection

AbstractMicrobial communities often perform important functions that depend on inter-species interactions. To improve community function via artificial selection, one can repeatedly grow many communities to allow mutations to arise, and “reproduce” the highest-functioning communities by partitioning each into multiple offspring communities for the next cycle. Since improvement is often unimpressive in experiments, we study how to design effective selection strategies in silico. Specifically, we simulate community selection to improve a function that requires two species. With a “community function landscape”, we visualize how community function depends on species and genotype compositions. Due to ecological interactions that promote species coexistence, the evolutionary trajectory of communities is restricted to a path on the landscape. This restriction can generate counter-intuitive evolutionary dynamics, prevent the attainment of maximal function, and importantly, hinder selection by trapping communities in locations of low community function heritability. We devise experimentally-implementable manipulations to shift the path to higher heritability, which speeds up community function improvement even when landscapes are high dimensional or unknown. Video walkthroughs: https://go.nature.com/3GWwS6j; https://online.kitp.ucsb.edu/online/ecoevo21/shou2/.

scholarly journals Between migration load and evolutionary rescue: dispersal, adaptation and the response of spatially structured populations to environmental change

2014 ◽  
Vol 281 (1778) ◽  
pp. 20132795 ◽  
Author(s):  
Elizabeth C. Bourne ◽  
Greta Bocedi ◽  
Justin M. J. Travis ◽  
Robin J. Pakeman ◽  
Rob W. Brooker ◽  
...  
Keyword(s):  
Evolutionary Dynamics ◽  
Structured Populations ◽  
Evolutionary Potential ◽  
Beneficial Effects ◽  
Individual Fitness ◽  
Spatially Structured Populations ◽  
Local Selection ◽  
Evolutionary Response ◽  
Evolutionary Rescue ◽  
Opposing Effects

The evolutionary potential of populations is mainly determined by population size and available genetic variance. However, the adaptability of spatially structured populations may also be affected by dispersal: positively by spreading beneficial mutations across sub-populations, but negatively by moving locally adapted alleles between demes. We develop an individual-based, two-patch, allelic model to investigate the balance between these opposing effects on a population's evolutionary response to rapid climate change. Individual fitness is controlled by two polygenic traits coding for local adaptation either to the environment or to climate. Under conditions of selection that favour the evolution of a generalist phenotype (i.e. weak divergent selection between patches) dispersal has an overall positive effect on the persistence of the population. However, when selection favours locally adapted specialists, the beneficial effects of dispersal outweigh the associated increase in maladaptation for a narrow range of parameter space only (intermediate selection strength and low linkage among loci), where the spread of beneficial climate alleles is not strongly hampered by selection against non-specialists. Given that local selection across heterogeneous and fragmented landscapes is common, the complex effect of dispersal that we describe will play an important role in determining the evolutionary dynamics of many species under rapidly changing climate.

scholarly journals Eco-evolutionary dynamics of social dilemmas

2016 ◽  
Author(s):  
Chaitanya S. Gokhale ◽  
Christoph Hauert
Keyword(s):  
Social Interactions ◽  
Evolutionary Dynamics ◽  
Complex Dynamics ◽  
Social Dilemmas ◽  
Microbial Populations ◽  
Evolutionary Processes ◽  
Ecological Processes ◽  
Evolutionary Trajectory ◽  
Changes Over Time ◽  
Better Than

AbstractSocial dilemmas are an integral part of social interactions. Cooperative actions, ranging from secreting extra-cellular products in microbial populations to donating blood in humans, are costly to the actor and hence create an incentive to shirk and avoid the costs. Nevertheless, cooperation is ubiquitous in nature. Both costs and benefits often depend non-linearly on the number and types of individuals involved–as captured by idioms such as ‘too many cooks spoil the broth’ where additional contributions are discounted, or ‘two heads are better than one’ where cooperators synergistically enhance the group benefit. Interaction group sizes may depend on the size of the population and hence on ecological processes. This results in feedback mechanisms between ecological and evolutionary processes, which jointly affect and determine the evolutionary trajectory. Only recently combined eco-evolutionary processes became experimentally tractable in microbial social dilemmas. Here we analyse the evolutionary dynamics of non-linear social dilemmas in settings where the population fluctuates in size and the environment changes over time. In particular, cooperation is often supported and maintained at high densities through ecological fluctuations. Moreover, we find that the combination of the two processes routinely reveals highly complex dynamics, which suggests common occurrence in nature.

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