Vibratory communication in a spider: female responses to synthetic male vibrations

Abstract

1. Adult females of the spider Cupiennius salei respond to electronically synthesized and sequentially presented models of male courtship vibration with their own vibration. By varying the different parameters contained in the ‘male’ vibration we measured the respective importance of these parameters for the attractivity of the signal and thereby defined filter properties of the female's innate releasing mechanism. 2. Both spectral and temporal properties of the male vibration influence the number of female responses. The carrier frequency (CF), the duration of the silent period between subsequent syllables (PD), syllable duration (SD), and syllable repetition rate (SRR) are the most important features. Acceleration amplitude, syllable shape, number of syllables per syllable series, and the change of syllable amplitude within a series are clearly less influential on the male signal's attractivity. 3. Vibrations eliciting a maximum number of female responses have the following properties: CF 133 Hz, SD 105 ms, PD 169 ms, SRR (at a duty cycle of 40%) 3.8/s, acceleration amplitude increasing from 10 mm/s2 to 100 mm/s2 within a series of syllables, number of syllables within a series 12 to 14. Trade-off phenomena could be demonstrated for SD and PD. 4. The female is rather narrowly tuned to the natural vibrations of conspecific males. There are combinations of values, however, which are more effective than natural signals.