Electrophysiological Odorant Response in Moths

The antennae of 2- to 3-day-old virgin male and female moths were cut at the base of the flagellum. After removing the tip, one antenna was inserted between two glass electrodes filled with 0.1 M KCl solution. In each test, a 10-μl solution of each odorant was added onto a piece of filter paper (0.5 cm × 0.5 cm) and then inserted into a Pasteur pipette. About 100 ng/μl stock solutions of individual odorants and different doses of the mixture IAC were prepared with paraffin oil. A continuous airflow of 30 ml/s was produced by a stimulus controller (CS-55, Syntech, Kirchzarten, Germany). Odor stimulation was controlled by a puff of purified air (0.2 s at 10 ml/s airflow) from the CS-55. EAG signals were amplified with a 10× AC/DC headstage preamplifier (Syntech) and further acquired with an Intelligent Data Acquisition Controller (IDAC-4-USB, Syntech) (Cao et al. 2016 (link)). The signals were recorded, monitored, and analyzed using Syntech EAG-software (Syntech, Germany). The EAG response values for each compound were calculated by subtracting the value of the same antennae corresponding to a solvent blank of paraffin oil.