In the recent years, vibrational communication signals have become more and more prominent in research—often, characteristics of signals are described for several closely related species or populations of the same species, using means and standard deviations. Phenotypic variation in vibratory communication signals can be measured and compared using the coefficient of variation, which is supposed to be independent of trait size. However, it has been shown that the coefficients of variation of acoustic (airborne sound) male courtship signals in insects and anurans increase with signal duration in accordance with a power law. To examine whether this pattern is also true for vibrational communication signals, we used original data for Mantophasmatodea and reviewed the literature for published data on arthropods, anurans and mammals. The relationship between trait variability and duration is surprisingly stable for all investigated biotremology data and similar to the relationships found for airborne sound courtship signals. This study adds towards our knowledge about a general pattern for temporal variability of communication signals. [ABSTRACT FROM AUTHOR]