title: Mammal pollinators lured by the scent of a parasitic plant.
abstract: To communicate with animals, plants use signals that are distinct from their surroundings. Animals generally learn to use these signals through associative conditioning; however, signals are most effective when they elicit innate behavioural responses. Many plant species have flowers specialized for pollination by ground-dwelling mammals, but the signals used to attract these pollinators have not been elucidated. Here, we demonstrate the chemical basis for attraction of mammal pollinators to flowers of the dioecious parasitic plant Cytinus visseri (Cytinaceae). Two aliphatic ketones dominate the scent of this species; 3-hexanone, which elicits strong innate attraction in rodents, and 1-hexen-3-one, which repels them in isolation, but not in combination with 3-hexanone. The aliphatic ketone-dominated scent of C. visseri contrasts with those of insect-pollinated plants, which are typically dominated by terpenoids, aromatic or non-ketone aliphatic compounds. 3-hexanone is also known from some bat-pollinated species, suggesting independent evolution of plant signals in derived, highly specialized mammal-pollination systems.
authors.affiliation: School of Biological and Conservation Sciences, University of KwaZulu-Natal, Private Bag X01, Scottsville, Pietermaritzburg 3209, South Africa. johnsonsd@ukzn.ac.za
authors.forename: Steven D
authors.initials: SD
authors.lastname: Johnson
authors.forename: Priscilla M
authors.initials: PM
authors.lastname: Burgoyne
authors.forename: Lawrence D
authors.initials: LD
authors.lastname: Harder
authors.forename: Stefan
authors.initials: S
authors.lastname: Dötterl
mesh_terms: D000818:Animals; D005075:Biological Evolution; D002849:Chromatography, Gas; D035264:Flowers / Q000737:chemistry / Q000502:physiology; D006588:Hexanones / Q000032:analysis*; D019684:Magnoliopsida / Q000737:chemistry*; D009812:Odorants / Q000032:analysis*; D054817:Pollination / Q000502:physiology*; D012377:Rodentia / Q000502:physiology*; D013019:South Africa
chemical_list: D006588:Hexanones