Segestidea novaeguineae (Brancski, 1897)

Morris, Glenn K, Ingrisch, Sigfrid, Willemse, Fer, Willemse, Luc, De Luca, Paul A. & Klimas, Dita, 2025, Stridulation songs of some Tettigoniidae (Ensifera, Orthoptera) from Papua New Guinea, Zootaxa 5600 (1), pp. 1-81 : 33-35

Segestidea novaeguineae (Brancski, 1897)

( Figs 33 , 34 )

Specimens studied. (1 male) Papua New Guinea, McAdam Nat. Park , Bulolo Gorge, 28 viii 1981, Coll. G.K.Morris.

Systematics. The male fits perfectly the redescription (F. Willemse 1977, 1979).

Comments. Common name palm katydid. Several Sexava spp. are pests of Oil Palm ( Page 2005).

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.

Figures

FIGURE 33. Segestidea novaeguineae strigin:A) Figs 6,7 from F.Willemse 1977 clarifies venation posterior to Cu2 contributing to overmirror fold; B) Fig. 107 from F. Willemse 1977, straight file of many broad teeth, note absence of basal block; C) Dorsal aspect of right tegmen strigin showing fold cantilevers only modestly over mirror.

FIGURE 34. Segestidea novaeguineae sound analysis: B&K 2203 SL meter and 4165 ½” B&K microphone, equipment insensitive above 40 kHz.A) Coarse time resolution of song shows 19 phonatome emissions; B) One such phonatome at higher time resolution showing characteristically variable amplitudes; C) Time domain sample excerpt from B at high resolution; D) Spectrum of the sound in B, single broad low-Q peak centred on 9.4 kHz.