Electrophysiological Responses of Labellar Chemosensilla of a Wild Type and a Salt Tolerant Mutant (Lot-94) of Drosophila Melanogaster (Meigen) (Diptera Drosophilidae)

SUMMARY The labellar chemosensilla of a wild type strain (QA) and a «salt tolerant» mutant (Lot-94) of Drosophila melanogaster (Meigen) (Diptera Drosophilidae) were tested electrophysiologically in order to ascertain whether the altered feeding reflex response of the mutant is related to differences at the chemoreceptor or within the CNS. Four chemosensory units were identified in each chemosensillum of both strains: one unit was most sensitive to NaCl (M1) and a different one to sucrose (M2). The analysis of the spike frequencies of the M1 and M2 units in QA and Lot-94 flies indicates that the altered feeding behaviour observed in the mutant probably depends on variations within the CNS.