scholarly journals Experimental evolution of reproductive isolation from a single natural population

2018 ◽  
Author(s):  
Scott M. Villa ◽  
Juan C. Altuna ◽  
James S. Ruff ◽  
Andrew B. Beach ◽  
Lane I. Mulvey ◽  
...  
Keyword(s):  
Body Size ◽  
Natural Selection ◽  
Reproductive Isolation ◽  
Natural Population ◽  
Experimental Evolution ◽  
Natural Populations ◽  
Ecological Speciation ◽  
Phenotypic Trait ◽  
Sexual Competition ◽  
Feather Lice

Ecological speciation occurs when local adaptation generates reproductive isolation as a by-product of natural selection1–3. Although ecological speciation is a fundamental source of diversification, the mechanistic link between natural selection and reproductive isolation remains poorly understood, especially in natural populations2–6. Here we show that experimental evolution of parasite body size over four years (ca. 60 generations) leads to reproductive isolation in natural populations of feather lice on birds. When lice are transferred to pigeons of different sizes they rapidly evolve differences in body size that are correlated with host size. These size differences trigger mechanical mating isolation between lice that are locally adapted to the different sized hosts. Size differences among lice also influence the outcome of competition between males for access to females. Thus, body size directly mediates reproductive isolation through its influence on both inter-sexual compatibility and intra-sexual competition. Our results confirm that divergent natural selection acting on a single phenotypic trait can cause reproductive isolation to emerge from a single natural population in real time.

scholarly journals Rapid experimental evolution of reproductive isolation from a single natural population

2019 ◽  
Vol 116 (27) ◽  
pp. 13440-13445 ◽  
Author(s):  
Scott M. Villa ◽  
Juan C. Altuna ◽  
James S. Ruff ◽  
Andrew B. Beach ◽  
Lane I. Mulvey ◽  
...  
Keyword(s):  
Body Size ◽  
Natural Selection ◽  
Reproductive Isolation ◽  
Natural Population ◽  
Experimental Evolution ◽  
Natural Populations ◽  
Ecological Speciation ◽  
Phenotypic Trait ◽  
Divergent Natural Selection ◽  
Feather Lice

Ecological speciation occurs when local adaptation generates reproductive isolation as a by-product of natural selection. Although ecological speciation is a fundamental source of diversification, the mechanistic link between natural selection and reproductive isolation remains poorly understood, especially in natural populations. Here, we show that experimental evolution of parasite body size over 4 y (approximately 60 generations) leads to reproductive isolation in natural populations of feather lice on birds. When lice are transferred to pigeons of different sizes, they rapidly evolve differences in body size that are correlated with host size. These differences in size trigger mechanical mating isolation between lice that are locally adapted to the different sized hosts. Size differences among lice also influence the outcome of competition between males for access to females. Thus, body size directly mediates reproductive isolation through its influence on both intersexual compatibility and intrasexual competition. Our results confirm that divergent natural selection acting on a single phenotypic trait can cause reproductive isolation to emerge from a single natural population in real time.

scholarly journals GENETIC LOAD IN NATURAL POPULATIONS: IS IT COMPATIBLE WITH THE HYPOTHESIS THAT MANY POLYMORPHISMS ARE MAINTAINED BY NATURAL SELECTION?

Genetics ◽  
1974 ◽  
Vol 77 (3) ◽  
pp. 569-589
Author(s):  
Martin L Tracey ◽  
Francisco J Ayala
Keyword(s):  
Drosophila Melanogaster ◽  
Natural Selection ◽  
Natural Population ◽  
Natural Populations ◽  
Genetic Load ◽  
Structural Genes ◽  
Invertebrate Species ◽  
Average Proportion ◽  
Mean Fitness ◽  
The Mean

ABSTRACT Recent studies of genetically controlled enzyme variation lead to an estimation that at least 30 to 60% of the structural genes are polymorphic in natural populations of many vertebrate and invertebrate species. Some authors have argued that a substantial proportion of these polymorphisms cannot be maintained by natural selection because this would result in an unbearable genetic load. If many polymorphisms are maintained by heterotic natural selection, individuals with much greater than average proportion of homozygous loci should have very low fitness. We have measured in Drosophila melanogaster the fitness of flies homozygous for a complete chromosome relative to normal wild flies. A total of 37 chromosomes from a natural population have been tested using 92 experimental populations. The mean fitness of homozygous flies is 0.12 for second chromosomes, and 0.13 for third chromosomes. These estimates are compatible with the hypothesis that many (more than one thousand) loci are maintained by heterotic selection in natural populations of D. melanogaster.

scholarly journals Assortative flocking in crossbills and implications for ecological speciation

2012 ◽  
Vol 279 (1745) ◽  
pp. 4223-4229 ◽  
Author(s):  
Julie W. Smith ◽  
Stephanie M. Sjoberg ◽  
Matthew C. Mueller ◽  
Craig W. Benkman
Keyword(s):  
Natural Selection ◽  
Reproductive Isolation ◽  
Assortative Mating ◽  
Ecological Speciation ◽  
Central Question ◽  
Loxia Curvirostra ◽  
Call Type ◽  
Divergent Natural Selection ◽  
Contact Calls ◽  
Red Crossbills

How reproductive isolation is related to divergent natural selection is a central question in speciation. Here, we focus on several ecologically specialized taxa or ‘call types’ of red crossbills ( Loxia curvirostra complex), one of the few groups of birds providing much evidence for ecological speciation. Call types differ in bill sizes and feeding capabilities, and also differ in vocalizations, such that contact calls provide information on crossbill phenotype. We found that two call types of red crossbills were more likely to approach playbacks of their own call type than those of heterotypics, and that their propensity to approach heterotypics decreased with increasing divergence in bill size. Although call similarity also decreased with increasing divergence in bill size, comparisons of responses to familiar versus unfamiliar call types indicate that the decrease in the propensity to approach heterotypics with increasing divergence in bill size was a learned response, and not a by-product of calls diverging pleiotropically as bill size diverged. Because crossbills choose mates while in flocks, assortative flocking could lead indirectly to assortative mating as a by-product. These patterns of association therefore provide a mechanism by which increasing divergent selection can lead to increasing reproductive isolation.

scholarly journals Pre- and post-mating reproductive isolation evolve independently during rapid adaptation to high temperature

2021 ◽  
Author(s):  
Sheng-Kai Hsu ◽  
Wei-Yun Lai ◽  
Johannes Novak ◽  
Felix Lehner ◽  
Ana Marija Jakšić ◽  
...  
Keyword(s):  
Reproductive Isolation ◽  
Natural Populations ◽  
Cuticular Hydrocarbon ◽  
Ecological Speciation ◽  
Temperature Adaptation ◽  
Rapid Adaptation ◽  
Epistatic Interactions ◽  
Males And Females ◽  
Altered Lipid Metabolism ◽  
Altered Lipid

Ambient temperature is one major ecological factor driving adaptation in natural populations, but its impact on the emergence of new species is not yet clear. Here, we explored the evolution of reproductive isolation during temperature adaptation by exposing 10 replicate Drosophila simulans populations to a hot temperature regime. Within less than 200 generations, both pre- and post-mating reproductive isolation evolved. The altered lipid metabolism of evolved flies also affected the cuticular hydrocarbon (CHCs) profiles. Different CHC profiles could explain the emerged assortative mating between ancestral and evolved populations. Hence, we identified the hallmark of ecological speciation driven by temperature adaptation. While this pre-mating isolation occurred only between ancestral and evolved replicate populations, post-mating reproductive isolation was observed among evolved replicate populations. We propose that epistatic interactions of reproduction-related genes between males and females resulted in adaptive co-evolution. Incompatibilities between different gene combinations favored in each replicate could explain the observed post-mating reproductive isolation. We anticipate that this mutation-order-like speciation from standing genetic variation, a new speciation process, is widespread in nature when highly polygenic traits are involved in adaptation.

scholarly journals Evidence for mutation-order speciation inSenecio lautus

2019 ◽  
Author(s):  
Maria C. Melo ◽  
Maddie E. James ◽  
Federico Roda ◽  
Diana Bernal-Franco ◽  
Melanie J. Wilkinson ◽  
...  
Keyword(s):  
Natural Selection ◽  
Reproductive Isolation ◽  
Animal Species ◽  
Growth Habit ◽  
Sand Dunes ◽  
Ecological Speciation ◽  
Divergent Natural Selection ◽  
Genetic Complexity ◽  
Comprehensive Test ◽  
Prostrate Growth

In a number of animal species, divergent natural selection has repeatedly and independently driven the evolution of reproductive isolation between populations adapted to contrasting, but not to similar environments1. This process is known as parallel ecological speciation, and examples in plants are enigmatically rare2. Here, we perform a comprehensive test of the ecological speciation hypothesis in an Australian wildflower where parapatric populations found in coastal sand dunes (Dune ecotype) and headlands (Headland ecotype) have repeatedly and independently diverged in growth habit. Consistent with a role for divergent natural selection driving the evolution of reproductive isolation, we found that Dune populations with erect growth habit were easy to transplant across sand dunes, were largely interfertile despite half-a-million years of divergence, and were reproductively isolated from equally divergent Headland populations with prostrate growth habit. However, we unexpectedly discovered that both extrinsic and intrinsic reproductive isolation has evolved between prostrate Headland populations, suggesting that populations evolving convergent phenotypes can also rapidly become new species. Mutation-order speciation2, where the random accumulation of adaptive alleles create genetic incompatibilities between populations inhabiting similar habitats, provides a compelling explanation for these complex patterns of reproductive isolation. Our results suggest that natural selection can drive speciation effectively, but environmental and genetic complexity might make parallel ecological speciation uncommon in plants despite strong morphological convergence.

scholarly journals Gradient Evolution of Body Colouration in Surface- and Cave-DwellingPoecilia mexicanaand the Role of Phenotype-Assortative Female Mate Choice

2013 ◽  
Vol 2013 ◽  
pp. 1-15 ◽  
Author(s):  
David Bierbach ◽  
Marina Penshorn ◽  
Sybille Hamfler ◽  
Denise B. Herbert ◽  
Jessica Appel ◽  
...  
Keyword(s):  
Natural Selection ◽  
Reproductive Isolation ◽  
Assortative Mating ◽  
Ecological Speciation ◽  
Divergent Selection ◽  
Gradual Change ◽  
Cave Fish ◽  
Resident Male ◽  
Poecilia Mexicana ◽  
Body Colouration

Ecological speciation assumes reproductive isolation to be the product of ecologically based divergent selection. Beside natural selection, sexual selection via phenotype-assortative mating is thought to promote reproductive isolation. Using the neotropical fishPoecilia mexicanafrom a system that has been described to undergo incipient ecological speciation in adjacent, but ecologically divergent habitats characterized by the presence or absence of toxic H2S and darkness in cave habitats, we demonstrate a gradual change in male body colouration along the gradient of light/darkness, including a reduction of ornaments that are under both inter- and intrasexual selection in surface populations. In dichotomous choice tests using video-animated stimuli, we found surface females to prefer males from their own population over the cave phenotype. However, female cave fish, observed on site via infrared techniques, preferred to associate with surface males rather than size-matched cave males, likely reflecting the female preference for better-nourished (in this case: surface) males. Hence, divergent selection on body colouration indeed translates into phenotype-assortative mating in the surface ecotype, by selecting against potential migrant males. Female cave fish, by contrast, do not have a preference for the resident male phenotype, identifying natural selection against migrants imposed by the cave environment as the major driver of the observed reproductive isolation.

scholarly journals Ant collective behavior is heritable and shaped by selection

2019 ◽  
Author(s):  
Justin T. Walsh ◽  
Simon Garnier ◽  
Timothy A. Linksvayer
Keyword(s):  
Body Size ◽  
Natural Selection ◽  
Sex Ratio ◽  
Collective Behavior ◽  
Genetic Correlations ◽  
Natural Populations ◽  
The Body ◽  
Collective Behaviors ◽  
Fitness Consequences ◽  
Caste Ratio

AbstractCollective behaviors are widespread in nature and usually assumed to be strongly shaped by natural selection. However, the degree to which variation in collective behavior is heritable and has fitness consequences -- the two prerequisites for evolution by natural selection -- is largely unknown. We used a new pharaoh ant (Monomorium pharaonis) mapping population to estimate the heritability, genetic correlations, and fitness consequences of three collective behaviors (foraging, aggression, and exploration) as well as body size, sex ratio, and caste ratio. Heritability estimates for the collective behaviors were moderate, ranging from 0.17 to 0.32, but lower than our estimates for the heritability of caste ratio, sex ratio, and the body size of new workers, queens, and males. Moreover, variation among colonies in collective behaviors was phenotypically correlated, suggesting that selection may shape multiple colony collective behaviors simultaneously. Finally, we found evidence for directional selection that was similar in strength to estimates of selection in natural populations. Altogether, our study begins to elucidate the genetic architecture of collective behavior and is one of the first studies to demonstrate that it is shaped by selection.

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