Eubliastes spp

Woodrow, Charlie & Montealegre-Z, Fernando, 2023, Auditory system biophysics in a new species of false-leaf katydid (Tettigoniidae: Pseudophyllinae) supports a hypothesis of broadband ultrasound reception, Zoologischer Anzeiger 304, pp. 94-104 : 101

4.2. Acoustics of Eubliastes spp .

The song of E. viridicorpus is classic for members of the Cocconotini , showing discrete pure tone pulses with a similar envelope structure to other pseudophyllines ( Baker et al., 2019; Stumpner et al., 2013) peaks at 23.4 kHz and is most similar to that of E. aethiops , which is also comprised of two syllables at a similar peak frequency (23.9 kHz, Fig. A1 ). However in E. aethiops the frequency spectrum has a wider bandwidth of 11.9 kHz (20 dB below the peak) compared to 2.2 kHz in E. viridicorpus , and does not show the additional frequency component towards 12 kHz as seen in E. viridicorpus . This song peak frequency range seems to be characteristic of the genus with E. chlorodictyon and E. pollonerae singing at and 25.4 and 25.5 kHz respectively ( Figs. A2 ,A 3 ; Montealegre-Z and Morris, 1999; ter Hofstede et al., 2020).The same could be said of the two syllable temporal pattern of the song, but more recordings of other extant species (acoustic data is currently only available for four species) would be beneficial for future comparisons. The song of E. viridicorpus is also interesting in that the high amplitude component is at the start of each syllable rather than the end. This is similar to the song structure of E. chlorodictyon ( Montealegre-Z and Morris, 1999), but differs from E. aethiops ( Fig. A1 ) and E. pollonerae ( ter Hofstede et al., 2020) . This difference is not due to differences in stridulatory file anatomy, but instead indicates that the pattern of wing motion during stridulation differs, as the loudest component of the signal is produced during wing closure (Montealegre-Z., 2005; Montealegre-Z et al., 2006; Nielsen and Dreisig, 1970). Although tremulation was observed in the field, we were not able to record tremulatory signals in the laboratory. We hypothesise that E. viridicorpus utilises wing velocity to generate the lower peak of the song spectrum, but with a mirror tuned to the higher frequency peak of the spectrum (the first order harmonic) to optimise energy use.

Figures

Fig. 1. Eubliastes viridicorpus sp. nov. A. male face; B. female face; C, male alive; D. illustrated male habitus; E, illustrated male terminalia in ventral (i), dorsal (ii), and lateral (iii) views with lateral view of left cercus (iv); F, female terminalia in ventral (i), dorsal (ii), and lateral (iii) views with lateral close up of ovipositor tip (iv). Note, colours of the face in A and B are an artifact of alcohol preservation, but markings remain accurate. Illustrations by CW.

Fig. 2. Eubliastes viridicorpus sp. nov. acoustics. A, dorsal view of male stridulatory apparatus with tegmina closed; B, dorsal view of male stridulatory apparatus with tegmina open; C, male stridulatory file; D, male calling song waveform and spectrogram; E, waveform and spectrogram of single pulse, with high resolution inset of the dual tone waveform; F, male calling song frequency spectrum. Spectrogram parameters: FFT size = 512; Hamming window = 50% overlap; frequency resolution = 500 Hz.

Fig. 3. Eubliastes viridicorpus sp. nov. auditory system. A. male auditory system: (left to right) acoustic spiracle, acoustic trachea, auditory pinnae; B. female auditory system (left to right same as A); C. female auditory pinnae resonances; D. male auditory pinnae resonances; E, auditory pinnae resonances across other species of the genus Eubliastes. Abbreviations: Lapc, Left anterior pinna cavity; Rapc, Right anterior pinna cavity; Lppc, Left posterior pinna cavity; Rppc, Right posterior pinna cavity.