title: Trichobaris weevils distinguish amongst toxic host plants by sensing volatiles that do not affect larval performance.
abstract: Herbivorous insects use plant metabolites to inform their host plant selection for oviposition. These host-selection behaviours are often consistent with the preference-performance hypothesis; females oviposit on hosts that maximize the performance of their offspring. However, the metabolites used for these oviposition choices and those responsible for differences in offspring performance remain unknown for ecologically relevant interactions. Here, we examined the host-selection behaviours of two sympatric weevils, the Datura (Trichobaris compacta) and tobacco (T. mucorea) weevils in field and glasshouse experiments with transgenic host plants specifically altered in different components of their secondary metabolism. Adult females of both species strongly preferred to feed on D. wrightii rather than on N. attenuata leaves, but T. mucorea preferred to oviposit on N. attenuata, while T. compacta oviposited only on D. wrightii. These oviposition behaviours increased offspring performance: T. compacta larvae only survived in D. wrightii stems and T. mucorea larvae survived better in N. attenuata than in D. wrightii stems. Choice assays with nicotine-free, JA-impaired, and sesquiterpene-over-produced isogenic N. attenuata plants revealed that although half of the T. compacta larvae survived in nicotine-free N. attenuata lines, nicotine did not influence the oviposition behaviours of both the nicotine-adapted and nicotine-sensitive species. JA-induced sesquiterpene volatiles are key compounds influencing T. mucorea females' oviposition choices, but these sesquiterpenes had no effect on larval performance. We conclude that adult females are able to choose the best host plant for their offspring and use chemicals different from those that influence larval performance to inform their oviposition decisions.
authors.affiliation: Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, Jena, D-07745, Germany.|School of Biological Science, Seoul National University, 599 Gwanak-ro, Gwanak-gu, Seoul, 08826, Korea.
authors.forename: Gisuk
authors.initials: G
authors.lastname: Lee
authors.affiliation: Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, Jena, D-07745, Germany.
authors.forename: Youngsung
authors.initials: Y
authors.lastname: Joo
authors.affiliation: Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, Jena, D-07745, Germany.
authors.forename: Celia
authors.initials: C
authors.lastname: Diezel
authors.affiliation: School of Biological Science, Seoul National University, 599 Gwanak-ro, Gwanak-gu, Seoul, 08826, Korea.
authors.forename: Eun Ju
authors.initials: EJ
authors.lastname: Lee
authors.affiliation: Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, Jena, D-07745, Germany.
authors.forename: Ian T
authors.initials: IT
authors.lastname: Baldwin
authors.affiliation: Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, Jena, D-07745, Germany.
authors.forename: Sang-Gyu
authors.initials: SG
authors.lastname: Kim
mesh_terms: D000818:Animals; D032302:Datura / Q000737:chemistry; D005260:Female; D060434:Herbivory; D007814:Larva / Q000187:drug effects; D009538:Nicotine / Q000737:chemistry; D010058:Oviposition; D018515:Plant Leaves / Q000737:chemistry*; D030821:Plants, Genetically Modified / Q000737:chemistry; D014026:Nicotiana / Q000737:chemistry; D055549:Volatile Organic Compounds / Q000737:chemistry*; D048889:Weevils / Q000187:drug effects / Q000502:physiology*
chemical_list: D055549:Volatile Organic Compounds; D009538:Nicotine
keywords: Datura wrightii; Nicotiana attenuata; Trichobaris compacta; Trichobaris mucorea; host selection behaviour; secondary metabolites