title: Ceropegia sandersonii Mimics Attacked Honeybees to Attract Kleptoparasitic Flies for Pollination.
abstract: Four to six percent of plants, distributed over different angiosperm families, entice pollinators by deception [1]. In these systems, chemical mimicry is often used as an efficient way to exploit the olfactory preferences of animals for the purpose of attracting them as pollinators [2,3]. Here, we report a very specific type of chemical mimicry of a food source. Ceropegia sandersonii (Apocynaceae), a deceptive South African plant with pitfall flowers, mimics attacked honeybees. We identified kleptoparasitic Desmometopa flies (Milichiidae) as the main pollinators of C. sandersonii. These flies are well known to feed on honeybees that are eaten by spiders, which we thus predicted as the model chemically mimicked by the plant. Indeed, we found that the floral scent of C. sandersonii is comparable to volatiles released from honeybees when under simulated attack. Moreover, many of these shared compounds elicited physiological responses in antennae of pollinating Desmometopa flies. A mixture of four compounds-geraniol, 2-heptanone, 2-nonanol, and (E)-2-octen-1-yl acetate-was highly attractive to the flies. We conclude that C. sandersonii is specialized on kleptoparasitic fly pollinators by deploying volatiles linked to the flies' food source, i.e., attacked and/or freshly killed honeybees. The blend of compounds emitted by C. sandersonii is unusual among flowering plants and lures kleptoparasitic flies into the trap flowers. This study describes a new example of how a plant can achieve pollination through chemical mimicry of the food sources of adult carnivorous animals.
authors.affiliation: Department of Ecology and Evolution, Plant Ecology, University of Salzburg, 5020 Salzburg, Austria; Department of Plant Systematics, University of Bayreuth, 95440 Bayreuth, Germany.
authors.forename: Annemarie
authors.initials: A
authors.lastname: Heiduk
authors.affiliation: Department of Life Sciences, Natural History Museum, London SW7 5BD, United Kingdom.
authors.forename: Irina
authors.initials: I
authors.lastname: Brake
authors.affiliation: Department of Biology, University of Bielefeld, 33615 Bielefeld, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: von Tschirnhaus
authors.affiliation: Department of Organic Chemistry, University of Bayreuth, 95440 Bayreuth, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Göhl
authors.affiliation: Department of Biology, Plant Chemical Ecology, Technische Universität Darmstadt, 64287 Darmstadt, Germany; School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, Private Bag X01, Scottsville 3209, South Africa.
authors.forename: Andreas
authors.initials: A
authors.lastname: Jürgens
authors.affiliation: School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, Private Bag X01, Scottsville 3209, South Africa.
authors.forename: Steven D
authors.initials: SD
authors.lastname: Johnson
authors.affiliation: Department of Plant Systematics, University of Bayreuth, 95440 Bayreuth, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Meve
authors.affiliation: Department of Ecology and Evolution, Plant Ecology, University of Salzburg, 5020 Salzburg, Austria. Electronic address: stefan.doetterl@sbg.ac.at.
authors.forename: Stefan
authors.initials: S
authors.lastname: Dötterl
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents; D029062:Apocynaceae / Q000502:physiology*; D001516:Bees; D000067558:Biological Mimicry; D004175:Diptera / Q000502:physiology*; D020387:Food Chain; D054817:Pollination; D013019:South Africa
chemical_list: D000970:Antineoplastic Agents