Mating behavior in Centruroides margaritatus, as in other scorpion species, includes a series of rapid rocking or shaking movements of the male ("juddering"). It has been suggested that substrate vibrations are generated by juddering and that females respond to them by approaching the male, but its functional significance remains little studied. For the first time, substrate vibrations produced by males during courtship in Centruroides margaritatus are documented. The male started juddering after his first physical contact with the female and only one type of male vibratory signal was registered. The signal is produced during a series of rapid shaking of the male s body from front to rear and consists of multiple short pulses. Each pulse is called a judder and several judders "a series". The average duration of each judder was 0.018±0.009s (n=50) with an interval of 0.028±0.013s (n=50); the average duration of each series of judders was 4.2±3.5s with an interval between series of 3.5±6.3s and a rate of 0.21±0.17 series per second. The females responded in 72% of the time to the males juddering. Rev. Biol. Trop. 57 (Suppl. 1): 267-274. Epub 2009 November 30.