Weak Disruptive Selection and Incomplete Phenotypic Divergence in Two Classic Examples of Sympatric Speciation: Cameroon Crater Lake Cichlids

2012 ◽  
Vol 180 (4) ◽  
pp. E90-E109 ◽  
Author(s):  
Christopher H. Martin
Keyword(s):  
Crater Lake ◽  
Sympatric Speciation ◽  
Disruptive Selection ◽  
Phenotypic Divergence

scholarly journals Sympatric speciation in Nicaraguan crater lake cichlid fish

Nature ◽  
2006 ◽  
Vol 439 (7077) ◽  
pp. 719-723 ◽  
Author(s):  
Marta Barluenga ◽  
Kai N. Stölting ◽  
Walter Salzburger ◽  
Moritz Muschick ◽  
Axel Meyer
Keyword(s):  
Crater Lake ◽  
Cichlid Fish ◽  
Sympatric Speciation

Sympatric speciation suggested by monophyly of crater lake cichlids

Nature ◽  
1994 ◽  
Vol 368 (6472) ◽  
pp. 629-632 ◽  
Author(s):  
Ulrich K. Schliewen ◽  
Diethard Tautz ◽  
Svante Pääbo
Keyword(s):  
Crater Lake ◽  
Sympatric Speciation

scholarly journals Speciation: more likely through a genetic or through a learned habitat preference?

2005 ◽  
Vol 272 (1571) ◽  
pp. 1455-1463 ◽  
Author(s):  
J.B Beltman ◽  
J.A.J Metz
Keyword(s):  
Reproductive Isolation ◽  
Habitat Preference ◽  
Sympatric Speciation ◽  
Genetic Mechanism ◽  
Dynamical Analysis ◽  
Disruptive Selection ◽  
Single Population ◽  
Preferred Habitat ◽  
Simultaneous Evolution ◽  
Evolution Proceeds

A problem in understanding sympatric speciation is establishing how reproductive isolation can arise when there is disruptive selection on an ecological trait. One of the solutions that has been proposed is that a habitat preference evolves, and that mates are chosen within the preferred habitat. We present a model where the habitat preference can evolve either by means of a genetic mechanism or by means of learning. Employing an adaptive-dynamical analysis, we show that evolution proceeds either to a single population of specialists with a genetic preference for their optimal habitat, or to a population of generalists without a habitat preference. The generalist population subsequently experiences disruptive selection. Learning promotes speciation because it increases the intensity of disruptive selection. An individual-based version of the model shows that, when loci are completely unlinked and learning confers little cost, the presence of disruptive selection most probably leads to speciation via the simultaneous evolution of a learned habitat preference. For high costs of learning, speciation is most likely to occur via the evolution of a genetic habitat preference. However, the latter only happens when the effect of mutations is large, or when there is linkage between genes coding for the different traits.

scholarly journals Sympatric Speciation in Threespine Stickleback: Why Not?

2011 ◽  
Vol 2011 ◽  
pp. 1-15 ◽  
Author(s):  
Daniel I. Bolnick
Keyword(s):  
Sexual Dimorphism ◽  
Assortative Mating ◽  
Intraspecific Competition ◽  
Gasterosteus Aculeatus ◽  
Theoretical Models ◽  
Sympatric Speciation ◽  
Threespine Stickleback ◽  
Disruptive Selection ◽  
Evolutionary Diversification ◽  
Trait Variance

Numerous theoretical models suggest that sympatric speciation is possible when frequency-dependent interactions such as intraspecific competition drive disruptive selection on a trait that is also subject to assortative mating. Here, I review recent evidence that both conditions are met in lake populations of threespine stickleback (Gasterosteus aculeatus). Nonetheless, sympatric speciation appears to be rare or absent in stickleback. If stickleback qualitatively fit the theoretical requirements for sympatric speciation, why do they not undergo sympatric speciation? I present simulations showing that disruptive selection and assortative mating in stickleback, though present, are too weak to drive speciation. Furthermore, I summarize empirical evidence that disruptive selection in stickleback drives other forms of evolutionary diversification (plasticity, increased trait variance, and sexual dimorphism) instead of speciation. In conclusion, core assumptions of sympatric speciation theory seem to be qualitatively reasonable for stickleback, but speciation may nevertheless fail because of (i) quantitative mismatches with theory and (ii) alternative evolutionary outcomes.

Evolutionary Branching in a Classical Model for Sympatric Speciation

2011 ◽  
Author(s):  
Michael Doebeli
Keyword(s):  
Reproductive Isolation ◽  
Adaptive Dynamics ◽  
Classical Model ◽  
Sympatric Speciation ◽  
Disruptive Selection ◽  
General Outcome ◽  
Wide Range ◽  
Genetic Mechanisms ◽  
Basic Concepts ◽  
Smith Model

This chapter begins by considering the Maynard Smith model. Much of this work concentrated on the genetic mechanisms for assortative mating and reproductive isolation, based on the assumption that the underlying niche ecology would generate disruptive selection. However, understanding the conditions under which disruptive selection arises in the first place is equally important, and indeed necessary for assessing whether diversification is a general outcome in the Maynard Smith model. The chapter then shows that disruptive selection and polymorphism are scenarios that occur generically, that is, for a wide range of parameters, in a classical and widely used speciation model. It also provides an introduction to some of the basic concepts of adaptive dynamics theory.

scholarly journals Complex histories of repeated gene flow in Cameroon crater lake cichlids cast doubt on one of the clearest examples of sympatric speciation

Evolution ◽  
2015 ◽  
Vol 69 (6) ◽  
pp. 1406-1422 ◽  
Author(s):  
Christopher H. Martin ◽  
Joseph S. Cutler ◽  
John P. Friel ◽  
Cyrille Dening Touokong ◽  
Graham Coop ◽  
...  
Keyword(s):  
Gene Flow ◽  
Crater Lake ◽  
Sympatric Speciation ◽  
Cast Doubt

Disruptive selection of shell colour in land snails: a mark–recapture study of Euhadra peliomphala simodae

2019 ◽  
Vol 129 (2) ◽  
pp. 323-333 ◽  
Author(s):  
Shun Ito ◽  
Junji Konuma
Keyword(s):  
Survival Rates ◽  
Field Studies ◽  
Bimodal Distribution ◽  
Land Snail ◽  
Land Snails ◽  
Disruptive Selection ◽  
Evolutionary Divergence ◽  
Colour Variation ◽  
Intermediate Phenotypes ◽  
Phenotypic Divergence

Abstract Many theoretical studies have suggested that disruptive selection plays an important role in phenotypic divergence, but few studies have determined the action of disruptive selection on phenotypic divergence via field studies. This study investigated the effect of disruptive selection on shell colour polymorphism in the Japanese land snail Euhadra peliomphala simodae to determine whether extreme phenotypes of snail shell colour are favoured over intermediate phenotypes. We conducted field surveys on an oceanic island with black, yellow and intermediate-coloured E. p. simodae snails. We captured and marked ~1800 individual snails and monitored their survival over 18 months. We quantified shell colours against images and examined the frequency distribution of shell colour variation. The variation exhibited a bimodal distribution with a far lower frequency of intermediate-coloured snails than of black or yellow snails. The population sizes of the three snail groups fluctuated synchronously with the changing seasons. Bayesian estimates showed lower survival rates for juvenile intermediate-coloured snails than for juvenile black and yellow snails, implying there was disruptive selection associated with shell colour. We suggest this disruptive selection may have resulted in the evolutionary divergence of the snail’s shell colour within the lineage having high shell colour variation.

scholarly journals Incipient sympatric speciation via host race formation in Phengaris arion (Lepidoptera: Lycaenidae)

2019 ◽  
Vol 20 (1) ◽  
pp. 63-76 ◽  
Author(s):  
Judit Bereczki ◽  
Szilárd Póliska ◽  
Alex Váradi ◽  
János P. Tóth
Keyword(s):  
Negative Selection ◽  
Time Slot ◽  
Sympatric Speciation ◽  
Time Frame ◽  
Food Plants ◽  
Disruptive Selection ◽  
Incipient Speciation ◽  
Host Races ◽  
Host Race Formation ◽  
Race Formation

AbstractThe plausibility of sympatric speciation is still debated despite increasing evidence, such as host races in insects. This speciation process may be occurring in the case of the two phenological forms of the obligatorily myrmecophilous Phengaris arion. The main goal of our research was to study the nature and causes of difference between these forms focusing primarily on the incipient speciation via host races. Molecular analyses based on highly variable microsatellites together with Wolbachia screening, male genitalia morphometrics and host ant studies were carried out on four syntopic sample pairs. Our results show that the two phenological forms of P. arion may meet the criteria for host plant races. They coexist in sympatry in certain parts of the species range which is allowed by the adaptation to the distinct phenology of the host plants. Negative selection acts against the intermediate individuals which are on the wing in the inappropriate time frame. Thus, disruptive selection affects and produces bimodal distributions of phenotypes. However, the phenology of food plants is not entirely distinct and fluctuates year by year. Therefore, the two forms can exchange genes occasionally depending on the length of the time slot when they can meet with each other. Consequently, the reproductive isolation could not be completed and the existence of the two arion forms may represent only an incipient stage of sympatric speciation. It is also clear that Wolbachia is likely not a driver of sympatric speciation in this case.

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