Supplementary material S26: A comparison of the spectral features of the loudest jolt against walking vibrations on each substrate.

A series of spectrograms allowing the comparison of the vibration originating from the loudest jolt on the left column and walking behaviour on the right column, on three separate substrates (petri-dish (a and b), empty honeycomb (c and d), brood-comb (e and f). The magnitude of acceleration is logarithmic (to the base 10), where the highest magnitude is dark red (2.1x10^-3 m/s²) and the lowest magnitude dark blue (and forced to 1/200 of the maximum). All six panels are scaled identically for ease of comparison. In each spectrogram, the regular background vibration inherent to the room was calculated and subtracted, but still results in red pixels on the very lowest frequency band. The data observed in each panel is that also used in S24.