title: The floral scent of Taccarum ulei (Araceae): attraction of scarab beetle pollinators to an unusual aliphatic acyloin.
abstract: The strongly fragrant thermogenic inflorescences of Taccarum ulei (Araceae) are highly attractive to night-active scarab beetles of Cyclocephala celata and C. cearae (Scarabaeidae, Cyclocephalini), which are effective pollinators of plants in the wild in northeastern Brazil. GC-MS analysis of headspace floral scent samples of T. ulei established that two constituents, (S)-2-hydroxy-5-methyl-3-hexanone (an aliphatic acyloin rarely detected in flowers) and dihydro-β-ionone (an irregular terpene) accounted for over 96% of the total scent discharge. Behavioral tests (in both field and cages) showed that male and female C. celata and C. cearae were attracted to traps baited with a synthetic mixture of both compounds; however, they were also responsive to (S)-2-hydroxy-5-methyl-3-hexanone alone, which thus functions as a specific attractive cue. These findings support other recent research in suggesting that angiosperms pollinated by cyclocephaline scarab beetles release floral odors of limited complexity in terms of numbers of compounds, but often dominated by unusual compounds that may ensure attraction of specific pollinator species.
authors.affiliation: Departamento de Química Fundamental, Universidade Federal de Pernambuco, Recife 50740-560, Brazil. artur_campos_maia@yahoo.com.br
authors.forename: Artur Campos Dália
authors.initials: AC
authors.lastname: Maia
authors.forename: Marc
authors.initials: M
authors.lastname: Gibernau
authors.forename: Stefan
authors.initials: S
authors.lastname: Dötterl
authors.forename: Daniela Maria do Amaral Ferraz
authors.initials: DM
authors.lastname: Navarro
authors.forename: Karlheinz
authors.initials: K
authors.lastname: Seifert
authors.forename: Tobias
authors.initials: T
authors.lastname: Müller
authors.forename: Clemens
authors.initials: C
authors.lastname: Schlindwein
mesh_terms: D000818:Animals; D029064:Araceae / Q000737:chemistry*; D001517:Coleoptera / Q000187:drug effects* / Q000502:physiology; D005233:Fatty Alcohols / Q000737:chemistry* / Q000494:pharmacology*; D005260:Female; D035264:Flowers / Q000737:chemistry*; D008297:Male; D015394:Molecular Structure; D009812:Odorants; D054817:Pollination
chemical_list: D005233:Fatty Alcohols; C011159:acyloin
keywords: (S)-2-Hydroxy-5-methyl-3-hexanone; Araceae; Behavioral tests; Cyclocephala celata and C. cearae; Dihydro-β-ionone; Floral volatiles; Taccarum ulei