Divergent host plant specialization as the critical driving force in speciation between populations of a phytophagous ladybird beetle.

Autor: Matsubayashi KW; Division of Environmental Biology, Faculty of Environmental Earth Science, Hokkaido University, Sapporo, Hokkaido, Japan. matsuba@sci.hokudai.ac.jp, Kahono S, Katakura H
Jazyk: angličtina
Zdroj: Journal of evolutionary biology [J Evol Biol] 2011 Jul; Vol. 24 (7), pp. 1421-32. Date of Electronic Publication: 2011 May 04.
DOI: 10.1111/j.1420-9101.2011.02274.x
Abstrakt: Detecting the isolating barrier that arises earliest in speciation is critically important to understanding the mechanism of species formation. We tested isolating barriers between host races of a phytophagous ladybird beetle, Henosepilachna diekei (Coleoptera: Coccinellidae: Epilachnine), that occur sympatrically on distinct host plants. We conducted field surveys for the distribution of the beetles and host plants, rearing experiments to measure six potential isolating factors (adult host preference, adult and larval host performance, sexual isolation, egg hatchability, F(1) hybrid inviability, and sexual selection against F(1) hybrids), and molecular analyses of mitochondrial ND2 and the nuclear ITS2 sequences. We found significant genetic divergence between the host races, and extremely divergent host preference (i.e. habitat isolation) and host performance (i.e. immigrant inviability), but no other isolating barriers. The fidelity to particular host plants arises first and alone can prevent gene flow between differentiating populations of phytophagous specialists.
(© 2011 The Authors. Journal of Evolutionary Biology © 2011 European Society For Evolutionary Biology.)
Databáze: MEDLINE
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