scholarly journals Dispersal behaviour as the outcome and trigger of multilevel selection in a social spider

2019 ◽  
Author(s):  
Zsóka Vásárhelyi ◽  
Jonathan N. Pruitt ◽  
István Scheuring
Keyword(s):  
Empirical Studies ◽  
Natural Populations ◽  
Characteristic Size ◽  
Multilevel Selection ◽  
Dispersal Behaviour ◽  
Behavioural Phenotype ◽  
Social Spider ◽  
Parameter Ranges ◽  
Evolutionary Simulations ◽  
Colony Level

AbstractThe facultatively social spider Anelosimus studiosus offers a unique opportunity for understanding how multilevel selection acts in natural populations. However, the importance of previous empirical studies are shaded by a conceptual debate about whether colony-level selection is truly present in these populations or not. Here we introduce a detailed individual based model, where practically all assumptions are supported by empirical data. The only element of the female A. studiosus life cycle missing from the literature is how maturing female spiders decide whether to disperse. This behavioural component we estimate with evolutionary simulations. This model is able to recapitulate the characteristic size and composition distributions of natural populations in different environments. The evolutionary simulations revealed that the optimal dispersal behaviour of a maturing female varies both with her ecological environment and behavioural phenotype. This finding is open for straightforward empirical testing. In agreement with empirical findings we have established parameter ranges where the population is prone to extinction without multiple-female nests. We propose that the dispersal behaviour of individuals is both the result and the prerequisite of multilevel selection in this species.

scholarly journals The Temporal Dynamics of Background Selection in Nonequilibrium Populations

Genetics ◽  
2020 ◽  
Vol 214 (4) ◽  
pp. 1019-1030 ◽  
Author(s):  
Raul Torres ◽  
Markus G. Stetter ◽  
Ryan D. Hernandez ◽  
Jeffrey Ross-Ibarra
Keyword(s):  
Natural Selection ◽  
Temporal Dynamics ◽  
Direct Action ◽  
Demographic History ◽  
Empirical Studies ◽  
Natural Populations ◽  
Background Selection ◽  
Size Change ◽  
Demographic Models ◽  
Classical Models

Neutral genetic diversity across the genome is determined by the complex interplay of mutation, demographic history, and natural selection. While the direct action of natural selection is limited to functional loci across the genome, its impact can have effects on nearby neutral loci due to genetic linkage. These effects of selection at linked sites, referred to as genetic hitchhiking and background selection (BGS), are pervasive across natural populations. However, only recently has there been a focus on the joint consequences of demography and selection at linked sites, and some empirical studies have come to apparently contradictory conclusions as to their combined effects. To understand the relationship between demography and selection at linked sites, we conducted an extensive forward simulation study of BGS under a range of demographic models. We found that the relative levels of diversity in BGS and neutral regions vary over time and that the initial dynamics after a population size change are often in the opposite direction of the long-term expected trajectory. Our detailed observations of the temporal dynamics of neutral diversity in the context of selection at linked sites in nonequilibrium populations provide new intuition about why patterns of diversity under BGS vary through time in natural populations and help reconcile previously contradictory observations. Most notably, our results highlight that classical models of BGS are poorly suited for predicting diversity in nonequilibrium populations.

scholarly journals Risky movement increases the rate of range expansion

2011 ◽  
Vol 279 (1731) ◽  
pp. 1194-1202 ◽  
Author(s):  
K. A. Bartoń ◽  
T. Hovestadt ◽  
B. L. Phillips ◽  
J. M. J. Travis
Keyword(s):  
Population Dynamics ◽  
Range Expansion ◽  
Movement Behaviour ◽  
Dispersal Behaviour ◽  
Dispersal Success ◽  
Movement Strategy ◽  
Development And Utilization ◽  
Evolutionary Simulations ◽  
Straight Lines ◽  
Movement Rules

The movement rules used by an individual determine both its survival and dispersal success. Here, we develop a simple model that links inter-patch movement behaviour with population dynamics in order to explore how individual dispersal behaviour influences not only its dispersal and survival, but also the population's rate of range expansion. Whereas dispersers are most likely to survive when they follow nearly straight lines and rapidly orient movement towards a non-natal patch, the most rapid rates of range expansion are obtained for trajectories in which individuals delay biasing their movement towards a non-natal patch. This result is robust to the spatial structure of the landscape. Importantly, in a set of evolutionary simulations, we also demonstrate that the movement strategy that evolves at an expanding front is much closer to that maximizing the rate of range expansion than that which maximizes the survival of dispersers. Our results suggest that if one of our conservation goals is the facilitation of range-shifting, then current indices of connectivity need to be complemented by the development and utilization of new indices providing a measure of the ease with which a species spreads across a landscape.

scholarly journals Limited potential for adaptation to climate change in a broadly distributed marine crustacean

2011 ◽  
Vol 279 (1727) ◽  
pp. 349-356 ◽  
Author(s):  
Morgan W. Kelly ◽  
Eric Sanford ◽  
Richard K. Grosberg
Keyword(s):  
Climate Change ◽  
Local Adaptation ◽  
Thermal Tolerance ◽  
Extinction Risk ◽  
Empirical Studies ◽  
Natural Populations ◽  
Adaptation To Climate Change ◽  
Isolated Populations ◽  
Tigriopus Californicus ◽  
Standing Variation

The extent to which acclimation and genetic adaptation might buffer natural populations against climate change is largely unknown. Most models predicting biological responses to environmental change assume that species' climatic envelopes are homogeneous both in space and time. Although recent discussions have questioned this assumption, few empirical studies have characterized intraspecific patterns of genetic variation in traits directly related to environmental tolerance limits. We test the extent of such variation in the broadly distributed tidepool copepod Tigriopus californicus using laboratory rearing and selection experiments to quantify thermal tolerance and scope for adaptation in eight populations spanning more than 17° of latitude. Tigriopus californicus exhibit striking local adaptation to temperature, with less than 1 per cent of the total quantitative variance for thermal tolerance partitioned within populations. Moreover, heat-tolerant phenotypes observed in low-latitude populations cannot be achieved in high-latitude populations, either through acclimation or 10 generations of strong selection. Finally, in four populations there was no increase in thermal tolerance between generations 5 and 10 of selection, suggesting that standing variation had already been depleted. Thus, plasticity and adaptation appear to have limited capacity to buffer these isolated populations against further increases in temperature. Our results suggest that models assuming a uniform climatic envelope may greatly underestimate extinction risk in species with strong local adaptation.

scholarly journals A theory of evolutionary dynamics on any complex spatial structure

2021 ◽  
Author(s):  
Yang Ping Kuo ◽  
César Nombela Arrieta ◽  
Oana Carja
Keyword(s):  
Bone Marrow ◽  
Stem Cell ◽  
Spatial Structure ◽  
Evolutionary Dynamics ◽  
Natural Populations ◽  
Spatial Arrangement ◽  
Death Process ◽  
Stem Cell Population ◽  
Evolutionary Simulations ◽  
Regular Networks

AbstractUnderstanding how the spatial arrangement of a population shapes its evolutionary dynamics has been of long-standing interest in population genetics. Most previous studies assume a small number of demes connected by migration corridors, symmetrical structures that most often act as well-mixed populations. Other studies use networks to model the more complex topologies of natural populations and to study the structures that suppress or amplify selection. However, they usually assume very small, regular networks, with strong constraints on the strength of selection considered. Here we build network generation algorithms, evolutionary simulations and derive general analytic approximations for probabilities of fixation in populations with complex spatial structure. By tuning network parameters and properties independent of each other, we systematically span across network families and show that both a network’s degree distribution, as well as its node mixing pattern shape the evolutionary dynamics of new mutations. We analytically write the relevant selective parameter, predictive of evolutionary dynamics, as a combination of network statistics. As one application, we use recent imaging datasets and build the cellular spatial networks of the stem cell niches of the bone marrow. Across a wide variety of parameters and regardless of the birth-death process used, we find these networks to be strong suppressors of selection, delaying mutation accumulation in this tissue. We also find that decreases in stem cell population size decrease the suppression strength of the tissue spatial structure, hinting at a potential diminishing spatial suppression in the bone marrow tissue as individuals age.

scholarly journals Repeatable aversion across threat types is linked with life-history traits but is dependent on how aversion is measured

2018 ◽  
Vol 5 (2) ◽  
pp. 172218 ◽  
Author(s):  
Gabrielle L. Davidson ◽  
Michael S. Reichert ◽  
Jodie M. S. Crane ◽  
William O'Shea ◽  
John L. Quinn
Keyword(s):  
Life History ◽  
Risk Aversion ◽  
Life History Traits ◽  
Empirical Studies ◽  
Natural Populations ◽  
Parus Major ◽  
Inspection Time ◽  
Life History Variation ◽  
Risk Avoidance ◽  
Personality Research

Personality research suggests that individual differences in risk aversion may be explained by links with life-history variation. However, few empirical studies examine whether repeatable differences in risk avoidance behaviour covary with life-history traits among individuals in natural populations, or how these links vary depending on the context and the way risk aversion is measured. We measured two different risk avoidance behaviours (latency to enter the nest and inspection time) in wild great tits ( Parus major ) in two different contexts—response to a novel object and to a predator cue placed at the nest-box during incubation---and related these behaviours to female reproductive success and condition. Females responded equally strongly to both stimuli, and although both behaviours were repeatable, they did not correlate. Latency to enter was negatively related to body condition and the number of offspring fledged. By contrast, inspection time was directly explained by whether incubating females had been flushed from the nest before the trial began. Thus, our inferences on the relationship between risk aversion and fitness depend on how risk aversion was measured. Our results highlight the limitations of drawing conclusions about the relevance of single measures of a personality trait such as risk aversion.

scholarly journals Sexually Antagonistic Cytonuclear Fitness Interactions inDrosophila melanogaster

Genetics ◽  
2001 ◽  
Vol 159 (1) ◽  
pp. 173-187 ◽  
Author(s):  
David M Rand ◽  
Andrew G Clark ◽  
Lisa M Kann
Keyword(s):  
Empirical Studies ◽  
Natural Populations ◽  
X Chromosomes ◽  
Disease Phenotypes ◽  
Fitness Effects ◽  
Wild Strains ◽  
Sexually Antagonistic Selection ◽  
Cytoplasmic Variation ◽  
Joint Transmission ◽  
Mtdna Haplotype

AbstractTheoretical and empirical studies have shown that selection cannot maintain a joint nuclear-cytoplasmic polymorphism within a population except under restrictive conditions of frequency-dependent or sex-specific selection. These conclusions are based on fitness interactions between a diploid autosomal locus and a haploid cytoplasmic locus. We develop a model of joint transmission of X chromosomes and cytoplasms and through simulation show that nuclear-cytoplasmic polymorphisms can be maintained by selection on X-cytoplasm interactions. We test aspects of the model with a “diallel” experiment analyzing fitness interactions between pairwise combinations of X chromosomes and cytoplasms from wild strains of Drosophila melanogaster. Contrary to earlier autosomal studies, significant fitness interactions between X chromosomes and cytoplasms are detected among strains from within populations. The experiment further demonstrates significant sex-by-genotype interactions for mtDNA haplotype, cytoplasms, and X chromosomes. These interactions are sexually antagonistic—i.e., the “good” cytoplasms in females are “bad” in males—analogous to crossing reaction norms. The presence or absence of Wolbachia did not alter the significance of the fitness effects involving X chromosomes and cytoplasms but tended to reduce the significance of mtDNA fitness effects. The negative fitness correlations between the sexes demonstrated in our empirical study are consistent with the conditions that maintain cytoplasmic polymorphism in simulations. Our results suggest that fitness interactions with the sex chromosomes may account for some proportion of cytoplasmic variation in natural populations. Sexually antagonistic selection or reciprocally matched fitness effects of nuclear-cytoplasmic genotypes may be important components of cytonuclear fitness variation and have implications for mitochondrial disease phenotypes that differ between the sexes.

scholarly journals Gene regulatory evolution in cold-adapted fly populations neutralizes plasticity and may undermine genetic canalization

2022 ◽  
Author(s):  
Yuheng Huang ◽  
Justin Lack ◽  
Grant Hoppel ◽  
John E Pool
Keyword(s):  
Gene Expression ◽  
Alternative Splicing ◽  
Adaptive Evolution ◽  
Empirical Studies ◽  
Natural Populations ◽  
Plastic Response ◽  
Cold Adapted ◽  
Thermal Environments ◽  
Gene Regulatory ◽  
Transcriptomic Level

The relationships between adaptive evolution, phenotypic plasticity, and canalization remain incompletely understood. Theoretical and empirical studies have made conflicting arguments on whether adaptive evolution may enhance or oppose the plastic response. Gene regulatory traits offer excellent potential to study the relationship between plasticity and adaptation, and they can now be studied at the transcriptomic level. Here we take advantage of three closely-related pairs of natural populations of Drosophila melanogaster from contrasting thermal environments that reflect three separate instances of cold tolerance evolution. We measure the transcriptome-wide plasticity in gene expression levels and alternative splicing (intron usage) between warm and cold laboratory environments. We find that suspected adaptive changes in both gene expression and alternative splicing tend to neutralize the ancestral plastic response. Further, we investigate the hypothesis that adaptive evolution can lead to decanalization of selected gene regulatory traits. We find strong evidence that suspected adaptive gene expression (but not splicing) changes in cold-adapted populations are more vulnerable to the genetic perturbation of inbreeding than putatively neutral changes. We find some evidence that these patterns may reflect a loss of genetic canalization accompanying adaptation, although other processes including hitchhiking recessive deleterious variants may contribute as well. Our findings augment our understanding of genetic and environmental effects on gene regulation in the context of adaptive evolution.

scholarly journals On the role of unequal exchange in the containment of transposable element copy number

1988 ◽  
Vol 52 (3) ◽  
pp. 223-235 ◽  
Author(s):  
Charles H. Langley ◽  
Elizabeth Montgomery ◽  
Richard Hudson ◽  
Norman Kaplan ◽  
Brian Charlesworth
Keyword(s):  
Transposable Element ◽  
Copy Number ◽  
Natural Populations ◽  
Crossing Over ◽  
Relevant Parameter ◽  
Normal Crossing ◽  
Unequal Exchange ◽  
Parameter Ranges ◽  
Transposable Element Copy

SummaryA population genetics model of the role of asymmetric pairing and unequal exchange in the stabilization of transposable element copy number in natural populations is proposed and analysed. Monte Carlo simulations indicate that the approximations incorporated into the analysis are robust in the relevant parameter ranges. Given several simple assumptions concerning transposition and excision, equal and unequal exchange, and chromosome structure, predictions of the relative numbers of transposable elements in various regions of the Drosophila melanogaster genome are compared to the observed distribution of roo/B104 elements across chromosomal regions with differing rates of exchange, and between X chromosomes and autosomes. There is no indication of an accumulation of elements in the distal regions of chromosomes, which is expected if unequal exchange is reduced concomitantly with normal crossing over in the distal regions. There is, however, an indication of an excess of elements relative to physical length in the proximal regions of the chromosomes, which also have restricted crossing over. This observation is qualitatively consistent with the model's predictions. The observed distribution of elements between the mid-sections of the X chromosomes and autosomes is consistent with the predictions of one of two models of unequal exchange.

scholarly journals Sex in the wild: how and why field-based studies contribute to solving the problem of sex

2017 ◽  
Author(s):  
Maurine Neiman ◽  
Patrick G. Meirmans ◽  
Tanja Schwander ◽  
Stephanie Meirmans
Keyword(s):  
Adaptive Evolution ◽  
Evolutionary Biology ◽  
Empirical Studies ◽  
Empirical Evaluation ◽  
Natural Populations ◽  
Strong Support ◽  
Niche Differentiation ◽  
In The Wild ◽  
Supplementary Material

AbstractWhy and how sexual reproduction is maintained in natural populations, the so-called “queen of problems”, is a key unanswered question in evolutionary biology. Recent efforts to solve the problem of sex have often emphasized results generated from laboratory settings. Here, we use a survey of representative “sex in the wild” literature to review and synthesize the outcomes of empirical studies focused on natural populations. Especially notable results included relatively strong support for mechanisms involving niche differentiation and a near absence of attention to adaptive evolution. Support for a major role of parasites is largely confined to a single study system, and only three systems contribute most of the support for mutation accumulation hypotheses. This evidence for taxon specificity suggests that outcomes of particular studies should not be more broadly extrapolated without extreme caution. We conclude by suggesting steps forward, highlighting tests of niche differentiation mechanisms in both lab and nature and empirical evaluation of adaptive evolution-focused hypotheses in the wild. We also emphasize the value of leveraging the growing body of genomic resources for non-model taxa to address whether the clearance of harmful mutations and spread of beneficial variants in natural populations proceeds as expected under various hypotheses for sex.Author contributionsSM and MN conceived the paper idea, SM, PM, MN, and TS designed the review strategy, reviewed and analysed the literature, and wrote the manuscript. All authors gave final approval for publication.Data archival locationThe results of our literature survey are provided as electronic supplementary material.

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