This figure depicts the processing for the detection of swarming in the post-training phase. Each hour-long averaged spectrum is compared, using the cross-correlation product (CCP), to a pair of DF (discriminant function) curves, as determined by the DFA algorithm, providing the co-ordinates for a single point in the DF space (green ‘+’ sign). From: Ramsey et al., (2020) The prediction of swarming in honeybee colonies using vibrational spectra. Scientific Reports 10: 9789.