title: Compound valence is conserved in binary odor mixtures in Drosophila melanogaster.
abstract: Most naturally occurring olfactory signals do not consist of monomolecular odorants but, rather, are mixtures whose composition and concentration ratios vary. While there is ample evidence for the relevance of complex odor blends in ecological interactions and for interactions of chemicals in both peripheral and central neuronal processing, a fine-scale analysis of rules governing the innate behavioral responses of Drosophila melanogaster towards odor mixtures is lacking. In this study we examine whether the innate valence of odors is conserved in binary odor mixtures. We show that binary mixtures of attractants are more attractive than individual mixture constituents. In contrast, mixing attractants with repellents elicits responses that are lower than the responses towards the corresponding attractants. This decrease in attraction is repellent-specific, independent of the identity of the attractant and more stereotyped across individuals than responses towards the repellent alone. Mixtures of repellents are either less attractive than the individual mixture constituents or these mixtures represent an intermediate. Within the limits of our data set, most mixture responses are quantitatively predictable on the basis of constituent responses. In summary, the valence of binary odor mixtures is predictable on the basis of valences of mixture constituents. Our findings will further our understanding of innate behavior towards ecologically relevant odor blends and will serve as a powerful tool for deciphering the olfactory valence code.
authors.affiliation: Max Planck Institute for Chemical Ecology, 07745 Jena, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Thoma
authors.affiliation: Max Planck Institute for Chemical Ecology, 07745 Jena, Germany hansson@ice.mpg.de mknaden@ice.mpg.de.
authors.forename: Bill S
authors.initials: BS
authors.lastname: Hansson
authors.affiliation: Max Planck Institute for Chemical Ecology, 07745 Jena, Germany hansson@ice.mpg.de mknaden@ice.mpg.de.
authors.forename: Markus
authors.initials: M
authors.lastname: Knaden
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D004331:Drosophila melanogaster / Q000187:drug effects*; D005260:Female; D007302:Insect Repellents / Q000494:pharmacology; D009812:Odorants; D009930:Organic Chemicals / Q000494:pharmacology; D012903:Smell
chemical_list: D007302:Insect Repellents; D009930:Organic Chemicals
keywords: Drosophila; Insect; Mixture; Olfaction