Parameters of vibrational signals produced by mechanisms other than abdomen vibration.

n = the number of signals analysed, N = the number of individuals analysed, where N is not specified then N = 1. Data are shown as mean ± SD when differences in parameter values between individuals were not significant and as minimal and maximal values when differences in parameter values between individuals were significant. For percussion signals we indicate the statistical test used to compare parameters of signals emitted as independent sequences (I) and parameters of signals emitted as a response to other vibrational emissions (R).