Figure 4. Light intensity had the same effect on all antennal treatments.

To test the effect of visual feedback and its possible interaction with antennal mechanosensory feedback on flower tracking, we performed all experiments both in bright (3000 lux) and dim (30 lux) light intensities. Hawkmoths showed reduced tracking performance of artificial flowers moving at higher frequencies in dim light, due to the slowing of their visual system (Figure 2—figure supplement 2, Figure 3—figure supplements 1,4). Here, we compare tracking performance between bright and dim light across antennal treatments. (A) We quantified the difference in frequency between light intensities at which moths reached a tracking error of 1 with the sum-of-sines stimulus. There was no significant difference (Supplementary file 8) between antennal conditions, suggesting that vision reduced tracking performance in dim light irrespective of the presence or absence of mechano-sensory feedback. (B) Similarly, there was no significant difference between the tracking performance in dim and bright light for the chirp stimulus (quantified as the difference of tracking abortion frequency at the two light conditions) (Supplementary file 6). (C–D) We determined the difference between the log-transformed magnitude spectra for thorax (C) and abdomen (D) jitter in bright and dim light. No significant effect of antennal condition was found using Friedman comparisons of the average difference in thorax or abdomen movements (Supplementary files 7 and 13). Lines show average, and shaded areas ± SEM.