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SEXUAL DIMORPHISM AND SPECIATION ON TWO ECOLOGICAL COINS: PATTERNS FROM NATURE AND THEORETICAL PREDICTIONS
Author(s) -
Cooper Idelle A.,
Gilman R. Tucker,
Boughman Janette Wenrick
Publication year - 2011
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/j.1558-5646.2011.01332.x
Subject(s) - sexual dimorphism , biology , gasterosteus , genetic algorithm , disruptive selection , sexual selection , ecological speciation , stickleback , evolutionary biology , ecological selection , ecology , competition (biology) , interspecific competition , selection (genetic algorithm) , allopatric speciation , adaptation (eye) , zoology , natural selection , genetic variation , population , gene flow , biochemistry , demography , artificial intelligence , fishery , sociology , neuroscience , fish <actinopterygii> , computer science , gene
Adaptive divergence of phenotypes, such as sexual dimorphism or adaptive speciation, can result from disruptive selection via competition for limited resources. Theory indicates that speciation and sexual dimorphism can result from identical ecological conditions, but co‐occurrence is unlikely because whichever evolves first should dissipate the disruptive selection necessary to drive evolution of the other. Here, we consider ecological conditions in which disruptive selection can act along multiple ecological axes. Speciation in lake populations of threespine sticklebacks ( Gasterosteus aculeatus ) has been attributed to disruptive selection due to competition for resources. Head shape in sticklebacks is thought to reflect adaptation to different resource acquisition strategies. We measure sexual dimorphism and species variation in head shape and body size in stickleback populations in two lakes in British Columbia, Canada. We find that sexual dimorphism in head shape is greater than interspecific differences. Using a numerical simulation model that contains two axes of ecological variation, we show that speciation and sexual dimorphism can readily co‐occur when the effects of loci underlying sexually dimorphic traits are orthogonal to those underlying sexually selected traits.