Electrophysiological responses of antennal receptor neurons in female Australian sheep blowflies, Lucilia cuprina, to host odours

Studies were conducted to investigate the electrophysiological responses of receptor neurons on the antennae of female Lucilia cuprina to putative sti mulants. Three distinct types of olfactory neurons were identified. Tests w ith 25 compounds showed 27 out of the 75 neurons examined responded best to racemic 1-octen-3-ol (Oct-best neuron), nine to dimethyldisulphide (DMDS-b est neuron) and seven to 2-phenylethanol (PE-best neuron). The remaining ce lls were not stimulated by any chemical stimulus presented, in this study. The olfactory neurons showed low spontaneous activities, 2,2 similar to 2.7 impulses/s, which increased significantly on stimulation with test compoun ds. Dose-dependent responses were observed with Oct-best neurons. Another t ype of neuron that had a much higher spontaneous activity (26 impulses/s) w as observed. This neuron did not respond to any of the candidate compounds tested but showed a decrease in activity with increased airflow over the an tennae and was termed the Airflow-sensitive neuron. The spontaneous activit ies of Oct-, DMDS-, PE-best and Airflow-sensitive neurons were inhibited by butanoic, pentanoic, hexanoic acids, and 3-methylindole. (C) 1998 Elsevier Science Ltd. All rights reserved.