title: Bacteria may contribute to distant species recognition in ant-aphid mutualistic relationships.
abstract: Mutualistic interactions between ant and aphid species have been the subject of considerable historical and contemporary investigations, the primary benefits being cleaning and protection for the aphids and carbohydrate-rich honeydew for the ants. Questions remained, however, as to the volatile semiochemical factor influencing this relationship. A recent study highlighted the role of bacterial honeydew volatile compounds in ant attraction. Here, ant's ability to distantly discriminate 2 aphid species was investigated based on bacterial honeydew semiochemicals emissions using a two-way olfactometer. Both the mutualistic aphid Aphis fabae L. and the nonmyrmecophilous aphid Acyrthosiphon pisum Harris were found to be attractive for the ant Lasius niger L. The level of attraction was similar in both assays (control vs. one of the aphid species). However, when given a choice between these 2 aphid species, ants showed a significant preference for Aphis fabae. Honeydew volatiles, mostly from bacterial origins, are known to be a key element in ant attraction. Using the same olfactometry protocol, the relative attractiveness of volatiles emitted by honeydews collected from each aphid species and by bacteria isolated from each honeydew was investigated. Again, ants significantly preferred volatiles released by Aphis fabae honeydew and bacteria. This information suggests that microbial honeydew volatiles enable ants to distantly discriminate aphid species. These results strengthen the interest of studying the occurrence and potential impact of microorganisms in insect symbioses.
authors.affiliation: Laboratory of Analytical Chemistry, University of Liege, Gembloux Agro-Bio Tech, Passage des Déportés 2, 5030, Gembloux, Belgium.
authors.forename: Christophe Y
authors.initials: CY
authors.lastname: Fischer
authors.affiliation: Unit of Social Ecology, Université Libre de Bruxelles, CP231, 50 avenue F. Roosevelt, B-1050, Brussels, Belgium.
authors.forename: Claire
authors.initials: C
authors.lastname: Detrain
authors.affiliation: Walloon Center of Industrial Biology, University of Liege, B40, Sart-Tilman, 4000, Liège, Belgium.
authors.forename: Philippe
authors.initials: P
authors.lastname: Thonart
authors.affiliation: Functional and Evolutionary Entomology, University of Liege, Gembloux Agro-Bio Tech, Passage des Déportés 2, 5030, Gembloux, Belgium.
authors.forename: Eric
authors.initials: E
authors.lastname: Haubruge
authors.affiliation: Functional and Evolutionary Entomology, University of Liege, Gembloux Agro-Bio Tech, Passage des Déportés 2, 5030, Gembloux, Belgium.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Francis
authors.affiliation: Functional and Evolutionary Entomology, University of Liege, Gembloux Agro-Bio Tech, Passage des Déportés 2, 5030, Gembloux, Belgium.
authors.forename: François J
authors.initials: FJ
authors.lastname: Verheggen
authors.affiliation: Laboratory of Analytical Chemistry, University of Liege, Gembloux Agro-Bio Tech, Passage des Déportés 2, 5030, Gembloux, Belgium.
authors.forename: Georges C
authors.initials: GC
authors.lastname: Lognay
mesh_terms: D000818:Animals; D001000:Ants / Q000502:physiology*; D001042:Aphids / Q000382:microbiology / Q000502:physiology*; D001419:Bacteria / Q000737:chemistry; D002755:Choice Behavior; D010675:Pheromones / Q000032:analysis; D012903:Smell; D013045:Species Specificity; D013559:Symbiosis; D055549:Volatile Organic Compounds / Q000032:analysis
chemical_list: D010675:Pheromones; D055549:Volatile Organic Compounds
keywords: VOC; ant; aphid; bacteria; honeydew; mutualism; recognition