Project: Investigations of the acoustic behavior of the parasitoid fly, Emblemasoma auditrix and its host Okanagana rimosa (Homoptera) Okanagana rimosa is a common cicada in habitats in Northern Michigan including areas close to the Biological Station. Its population is severely affected by a parasitic fungus and a parasitic fly. The biology of this parasitic fly, Emblemasoma auditrix, is in focus of the research project. After the discovery that the parasite has evolved a tympanal organ to home in on the sound producing host, the phonotactic behavior was studied in respect to sensory neurobiology. This ability of sound localisation with the very small ear (>500µm) of the fly is in focus of the current project. The precision of sound localization is tested behaviorally in the forest near the UMBS. In the field a transportable setup will be used, where fly behavior can be videotaped. During phonotaxis the fly often uses structures in the habitat for stops and presumably re-orientation towards the sound source. This re-orientation behavior will be analysed in detail, especially in respect to behavioral components allowing the fly to increase directionality of the ear. Further studies will also include parasitation rates and the impact on the host population. The data are the basis for models of search strategies and population biology in parasite-host-systems. Such models might also lead to an understanding of the evolution of the periodicity in cicadas.