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Odor-guided orientation in insects

For many insects smelling is the most important sense to find food, a partner or a nesting site. Orientation towards an odor source can be accomplished by simply moving along a concentration gradient or by zigzagging against the wind continuously catching up odor filaments.

One project of this PhD thesis is the investigation of olfactory orientation in ants. In some species odor trails are employed to guide workers to a rich food source and back to the nest entrance. Besides this, ants are known to navigate throughout their habitat using visual (i.e. celestial compass and visual landmarks) and proprioceptive cues (i.e. step integrator) We now research whether ants use olfactory landmarks. One part of this study will be carried out in the laboratory with Formica cunicullaria, and investigates ants' ability to learn a sequence of odors. Furthermore desert ants, Cataglyphis fortis in Tunisian salt pans are studied. We could show that desert ants use odor patterns as olfactory nest landmarks.

Another organism studied in this PhD thesis is the fruit fly Drosophila melanogaster. Over the past decades Drosophila had become a model organism in many study fields. Therefore much is known about olfaction, i.e. the reception on the level of receptor molecules, the signal transfer, the coupling and processing in the antennal lobes and higher instances. But so far few studies had been conducted concerning behavior. This study deals with the influence of an odors quality and quantity on the behavior of individual flies. Therefore a simple setup is employed where individual fruit flies are able to move towards and from an odor source that could be attractive or repellent.