SMILE

Stochastic Models for the Inference of Life Evolution

Refining the conditions for sympatric ecological speciation

Débarre, F.

Journal of Evolutionary Biology

2012

Can speciation occur in a single population when different types of resources are available, in the absence of any geographical isolation, or any spatial or temporal variation in selection? The controversial topics of sympatric speciation and ecological speciation have already stimulated many theoretical studies, most of them agreeing on the fact that mechanisms generating disruptive selection, some level of assortment, and enough heterogeneity in the available resources, are critical for sympatric speciation to occur. Few studies, however, have combined the three factors and investigated their interactions. In this article, I analytically derive conditions for sympatric speciation in a general model where the distribution of resources can be uni- or bimodal, and where a parameter controls the range of resources that an individual can exploit. This approach bridges the gap between models of a unimodal continuum of resources and Levene-type models with discrete resources. I then test these conditions against simulation results from a recently published article (Thibert-Plante \& Hendry, 2011, J. Evol. Biol. 24: 2186-2196) and confirm that sympatric ecological speciation is favoured when (i) selection is disruptive (i.e. individuals with an intermediate trait are at a local fitness minimum), (ii) resources are differentiated enough and (iii) mating is assortative. I also discuss the role of mating preference functions and the need (or lack thereof) for bimodality in resource distributions for diversification.

Bibtex

@article{debarre_refining_2012,
Author = {Débarre, F.},
Title = {Refining the conditions for sympatric ecological
speciation},
Journal = {Journal of Evolutionary Biology},
Volume = {25},
Number = {12},
Pages = {2651--2660},
Keywords = {Animals, Female, Genetic Speciation, Male, Models,
Genetic, Selection, Genetic, Sexual Behavior, Animal,
Sympatry},
abstract = {Can speciation occur in a single population when
different types of resources are available, in the
absence of any geographical isolation, or any spatial
or temporal variation in selection? The controversial
topics of sympatric speciation and ecological
speciation have already stimulated many theoretical
studies, most of them agreeing on the fact that
mechanisms generating disruptive selection, some level
of assortment, and enough heterogeneity in the
available resources, are critical for sympatric
speciation to occur. Few studies, however, have
combined the three factors and investigated their
interactions. In this article, I analytically derive
conditions for sympatric speciation in a general model
where the distribution of resources can be uni- or
bimodal, and where a parameter controls the range of
resources that an individual can exploit. This approach
bridges the gap between models of a unimodal continuum
of resources and Levene-type models with discrete
resources. I then test these conditions against
simulation results from a recently published article
(Thibert-Plante \& Hendry, 2011, J. Evol. Biol. 24:
2186-2196) and confirm that sympatric ecological
speciation is favoured when (i) selection is disruptive
(i.e. individuals with an intermediate trait are at a
local fitness minimum), (ii) resources are
differentiated enough and (iii) mating is assortative.
I also discuss the role of mating preference functions
and the need (or lack thereof) for bimodality in
resource distributions for diversification.},
doi = {10.1111/j.1420-9101.2012.02621.x},
issn = {1420-9101},
language = {eng},
month = dec,
pmid = {23020181},
year = 2012
}

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