Natural and Sexual Selection Giveth and Taketh Away Reproductive Barriers: Models of Population Divergence in Guppies
Authored by Andrew P Hendry, Jacques Labonne
Date Published: 2010
DOI: 10.1086/652992
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Platforms:
Java
CAPSIS
Model Documentation:
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Abstract
The standard predictions of ecological speciation might be nuanced by
the interaction between natural and sexual selection. We investigated
this hypothesis with an individual-based model tailored to the biology
of guppies (Poecilia reticulata). We specifically modeled the situation
where a high-predation population below a waterfall colonizes a
low-predation population above a waterfall. Focusing on the evolution of
male color, we confirm that divergent selection causes the appreciable
evolution of male color within 20 generations. The rate and magnitude of
this divergence were reduced when dispersal rates were high and when
female choice did not differ between environments. Adaptive divergence
was always coupled to the evolution of two reproductive barriers:
viability selection against immigrants and hybrids. Different types of
sexual selection, however, led to contrasting results for another
potential reproductive barrier: mating success of immigrants. In some
cases, the effects of natural and sexual selection offset each other, leading to no overall reproductive isolation despite strong adaptive
divergence. Sexual selection acting through female choice can thus
strongly modify the effects of divergent natural selection and thereby
alter the standard predictions of ecological speciation. We also found
that under no circumstances did divergent selection cause appreciable
divergence in neutral genetic markers.
Tags
sympatric speciation
Mate-choice
Rapid evolution
Life-history evolution
Ecological
speciation
Poecilia-reticulata
Female mating preferences
Host-plant
adaptation
Male color patterns
Trinidadian guppies