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ECB-ART-52310
Sci Adv 2023 Mar 31;913:eabm8157. doi: 10.1126/sciadv.abm8157.
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Disruptive selection and the evolution of discrete color morphs in Timema stick insects.

Villoutreix R , de Carvalho CF , Feder JL , Gompert Z , Nosil P .


Abstract
A major unresolved issue in biology is why phenotypic and genetic variation is sometimes continuous, yet other times packaged into discrete units of diversity, such as morphs, ecotypes, and species. In theory, ecological discontinuities can impose strong disruptive selection that promotes the evolution of discrete forms, but direct tests of this hypothesis are lacking. Here, we show that Timema stick insects exhibit genetically determined color morphs that range from weakly to strongly discontinuous. Color data from nature and a manipulative field experiment demonstrate that greater morph differentiation is associated with shifts from host plants exhibiting more continuous color variation to those exhibiting greater coloration distance between green leaves and brown stems, the latter of which generates strong disruptive selection. Our results show how ecological factors can promote discrete variation, and we further present results on how this can have variable effects on the genetic differentiation that promotes speciation.

PubMed ID: 37000882
Article link: Sci Adv
Grant support: [+]


References [+] :
Barrett, Linking a mutation to survival in wild mice. 2019, Pubmed