Figure 1. (a) Threshold curve for flight stop of tethered P. interpunctella males (n=8). Squares indicate the different intensities of the 50 kHz signal used in flight tunnel experiments. (b) Typical flight stop responses of a male P. interpunctella exposed to different intensities of a 50 ms stimulus at 50 kHz. Traces show the wing beat frequency of a male monitored by an infrared detector. The bar indicates the duration of ultrasound stimulation. A flight stop response is observed at both 75 dB SPL and 95 dB SPL, whereas no response is observed at 55 dB SPL, which is below the flight stop threshold of the species. Note that response latency decreases with increasing sound intensity. Intensities of the sound stimulus: upper trace: 55 dB SPL, middle trace: 75 dB SPL, lower trace: 95 dB SPL.