Vinegar flies (Drosophila melanogaster) show a highly selective behavior towards odor stimuli. A series of behavioral studies showed that a single olfactory stimulus is often not sufficient for immediate attraction to potential food sources or oviposition sites. Interestingly, the behavior differed between investigated D. melanogaster varieties, so-called "wildtypes". Natural odors (bananas, mangos) were preferred by most flies, whereas artificial flavors induced a more differentiated behavior. In addition, the nutritional condition of the animals, whether hungry or not, played a role. These studies confirm what researchers in the field of Chemical Ecology have observed with other organisms: that the behavior of animals, as well as plant responses to biotic or abiotic stress, are less regulated by an individual signal, but rather by a complex composition and amount of particular volatile compounds.
In their experiments the scientists used different varieties of vinegar flies that had already been characterized neurophysiologically: Canton-S, Oregon-R-C, Oregon R-S, Berlin-K, and wild-type Berlin. Electroantennographic measurements conducted before the actual behavioral experiments showed that all fly varieties showed an identical physiological response to five different chemical stimuli. Also, the vitality and mobility of the animals was similar. Nevertheless, the behavior, measured in periods of 24 hours, was different depending on fly variety and food (odor) supply: some varieties responded fast, others very slow. Equivalent behavioral studies on three additional fly varieties that had only recently been included in the strain collection (Dalby-HL, Helsingborg-E, and Helsingborg-F), proved especially interesting: these varieties turned out to be particularly selective and displayed slower and less strong responses to fruity smells, and especially to single odor components. "These flies, which have only until recently been living
|Contact: Bill S. Hansson|
Max Planck Institute for Chemical Ecology