Electrophysiological activity of labella and tarsal chemosensilla of Hybomitra lasiophthalma (Macquart) to stimulation with NaCl and various sugars

In the laboratory, the responses from the labellar and tarsal chemosensilla of adult females of Hybomitra lasiophthalma (Macq.) from Massachusetts, USA, to stimulation with salt or sugars (sucrose, glucose, fructose or galactose) were recorded electrophysiologically. The results demonstrated the existence of 4 chemosensory units (including units sensitive to water, salt and sugar separately) in each chemosensillum. Sensitivity thresholds for salt (above 50 mm) and sucrose (above 100 mm) were determined. Sucrose and galactose proved to be more active as stimulants than were fructose and glucose.