VARIATIONS IN SALT SENSITIVITY RELATED TO TYPE AND POSITION OF LABELLAR CHEMOSENSILLA IN PROTOPHORMIA-TERRAENOVAE

Electrophysiological responses to NaCl in the concentration range 1-10 00 mM were obtained from each of the 11 intermediate and 13 large labe llar chemosensilla in the blowfly Protophormia terraenovae. Up to thre e of the four chemoreceptor cells associated with each chemosensillum responded to NaCl in both sensillum types; the spike discharges of two of these cells were analysed and cross-compared. Differences in chemo receptor sensitivity and response pattern resulted between intermediat e and large sensilla. Sensitivity differences were found, by means of the cluster analysis, within each sensillum type in relation to sensil lar topology and are discussed in the light of a possible spatial cont ribution to the sensory coding process.