Bioacoustics of Segestidea novaeguineae

Distribution. The locality of this species is covered by the distribution as mapped in F. Willemse (1977 , 1979 ). Stridulation. Sustained over many seconds, the buzzes of the single recorded male ( Fig. 34A ) time resolved to regularly repeated wave trains of about 60 ms duration ( Fig. 34B ) with a regular period of a quarter second ( 0.25 s ). The trains are characterized by a highly erratic amplitude envelope ( Fig. 34B ). Spectrum frequencies formed one broad aggregate in the audio range ( Fig. 34D ): for 10 averaged calls this aggregate centred on 10.0 kHz. Though the spectrum is markedly low Q, the waveform of the pulse is not a train of distinctly time-separated transients and at higher time resolution these are seen to be almost sinusoid ( Fig 34C ); visible are distortions of the sine waves which might be the result of overloading the recording equipment or alternatively of a low sampling rate. A related species Sexava femorata C. Willemse , exhibits mandibular stridulation as a protest sound.A restrained female moved her labrum to and fro, sliding it “vertically over the anterior surface of her mandibles” ( Lloyd & Gurney 1975 ). Working with a recorder (Uher 4000 Report L) limited to the audio frequency range these authors found sound spectral energy for this defensive strigin near 3.5 kHz.