title: Na+/K+-ATPase resistance and cardenolide sequestration: basal adaptations to host plant toxins in the milkweed bugs (Hemiptera: Lygaeidae: Lygaeinae).
abstract: Despite sequestration of toxins being a common coevolutionary response to plant defence in phytophagous insects, the macroevolution of the traits involved is largely unaddressed. Using a phylogenetic approach comprising species from four continents, we analysed the ability to sequester toxic cardenolides in the hemipteran subfamily Lygaeinae, which is widely associated with cardenolide-producing Apocynaceae. In addition, we analysed cardenolide resistance of their Na(+)/K(+)-ATPases, the molecular target of cardenolides. Our data indicate that cardenolide sequestration and cardenolide-resistant Na(+)/K(+)-ATPase are basal adaptations in the Lygaeinae. In two species that shifted to non-apocynaceous hosts, the ability to sequester was secondarily reduced, yet Na(+)/K(+)-ATPase resistance was maintained. We suggest that both traits evolved together and represent major coevolutionary adaptations responsible for the evolutionary success of lygaeine bugs. Moreover, specialization on cardenolides was not an evolutionary dead end, but enabled this insect lineage to host shift to cardenolide-producing plants from distantly related families.
authors: Biozentrum Grindel, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany.
authors: Christiane
authors: C
authors: Bramer
authors: Biozentrum Grindel, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany.
authors: Susanne
authors: S
authors: Dobler
authors: Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Invalidenstrasse 43, 10115 Berlin, Germany.
authors: Jürgen
authors: J
authors: Deckert
authors: Am Stux, 53572 Unkel, Germany.
authors: Michael
authors: M
authors: Stemmer
authors: Biozentrum Grindel, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany Department of Ecology and Evolutionary Biology, Cornell University, Corson Hall, Ithaca, NY 14853, USA georg.petschenka@googlemail.com.
authors: Georg
authors: G
authors: Petschenka
mesh_terms: D000220:Adaptation, Biological; D000818:Animals; D029062:Apocynaceae / Q000254:growth & development; D005075:Biological Evolution; D002298:Cardenolides / Q000378:metabolism*; D020387:Food Chain; D020062:Heteroptera / Q000201:enzymology / Q000502:physiology*; D019476:Insect Proteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D000254:Sodium-Potassium-Exchanging ATPase / Q000235:genetics* / Q000378:metabolism
chemical_list: D002298:Cardenolides; D019476:Insect Proteins; D000254:Sodium-Potassium-Exchanging ATPase
keywords: Lygaeinae; Na+/K+-ATPase; adaptation; cardenolide; phylogeny; sequestration