Trichophallus capillatus Ingrisch, 2024

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 : 64-65

Trichophallus capillatus Ingrisch, 2024

( Figs 68 , 69 )

Material studied. Holotype male: Papua New Guinea, Wau , nr Wau Ecological Institute, 29 August 1981 coll. G.K. Morris.

Measurements. Male holotype, (length in mm): body 19; pronotum 4.8; tegmen 21.5; hind femur 12.5 mm.

Diagnosis. T. capillatus differs from other species of the genus described so far by the distinctive shape of the titillators on the male phallus ( Ingrisch 2024).

Comments. The file of T. capillatus ( Fig. 68 ).

Stridulation. Call a regular repetition of silence-separated trains of rapid-decay, single-tooth sourced, transient pulses ( Fig. 69 AB). The call manifests spectrally as a 25-kHz wide band of frequencies ( Fig. 69C ) centred near 48 kHz. The carrier frequency of this insect is entirely confined to the ultrasonic; there is no significant sound energy in the audio range. At the time resolution of Fig. 69A each train has a characteristically ‘top shaped’ amplitudeenvelope (a shape like a toy top lying on its side): pulse peak amplitudes begin very faintly, rise steadily then fall away again slightly over the last third. Stridulatory file count of 88–93 teeth reported by Ingrisch (2024) accords reasonably with the 68 transient rapid-decay pulses in the train shown in Fig. 69B . Mean values for 10 calls of our lone singer: trains 30 ms long, repeated with a mean period of 168 ms. The transients are somewhat erratically separated in time from each other within the train ( Fig. 69B ).

Broadband spectra should not be discounted as noisy stridulatory incompetence. Bands could theoretically be adaptive through ranging: differential attenuation of frequencies with distance is accentuated by a cluttered vegetation. The spectral shape of the band could be coding for distance, so helping to detect the trespass of a neighbouring male competitor or further the success of a female localizing her mate ( Morris et al. 2016).

Figures

FIGURE 68. Trichophallus capillatus sp. nov. holotype male: A) Stridulatory file, scale 1 mm; B) habitus dorsal view with left wings extended; C) habitus lateral view.

FIGURE 69. Trichophallus capillatus acoustic analysis: A) Two calls taken from a longer series, very faint to human ear; B) One call at higher time resolution showing train of transient pulses; C) Entirely ultrasonic broad band symmetrical spectrum, low-Q, centred near 50 kHz; recording made with ¼” B&K so flat to ~70 kHz.