Bioacoustics of Elbenia (Elbenia) paradigitata

Natural history. Compared to the more commonly sighted species Elbenia ( Elbenia ) tenera Brunner von Wattenwyl, 1878 , this species was found deep inside the forest, rather than along forest edge or roads. Calling song ( Fig. 4 ). The calling song is an isolated echeme made up of two syllables. The average echeme duration is 25.0±1.1 ms (22.8–27.2 ms). The first syllable consists of two pulses and has an average duration of 4.6±1.0 ms (3.0–6.7 ms). The first pulse is of a higher energy than the second one and of a slightly longer duration (1.3±0.3 vs. 1.1±0.3 ms). The second syllable consists of three short pulses (duration = 0.3–1.0 ms) followed by a longer pulse (duration = 1.3–2.1 ms). The initial three pulses are of distinctly lower energy than the last pulse; consecutive pulses are of higher energy. The average duration of the second syllable is 6.4±1.0 ms (4.7–9.4 ms). The average down time (silent interval between the two syllables) is 14.0±1.4 ms (10.8–16.9 ms). The average period of syllable is 18.6±0.9 ms (15.7–20.4 ms). The first syllable is usually of a slightly lower amplitude than the last pulse of the second syllable. The frequency spectrum is broadband and is not symmetrical and has a peak frequency of 23.5±0.8 kHz (22.0–24.7 kHz). The spectrum also has a secondary peak at 10.8±0.5 kHz (10.2–11.3 kHz).

Remarks. Our specimens most resemble Elbenia ( Elbenia ) paradigitata Gorochov, 2023 from Mount Trus Madi (see Gorochov, 2023b ). The black patch of the stridulatory area is very similar: its left tegmen having irregularly transverse black patch covering vein 1A but not reaching the mirror ( Fig. 3A ). The stridulatory file on the left tegmen also has a similar shape and similar number of teeth (circa 70) ( Fig. 3C ). The shape of the posterior lobe of the male tenth abdominal tergite is similarly slender and narrowly spaced apart; although these lobes can be flexible and appear wider than in its natural shape ( Figs 3D–F ). Their cerci are similar in their arcuate, long and slender shape, with its apical part directed medially and having an apex tooth-like ( Figs 3E–H ). The subgenital plate is stout, not necessarily surpassing the apices of the tenth abdominal tergite lobes; its apex with a groove at the base very narrow before widening at its apical end ( Figs 3E, 3F, 3H ).