Bioacoustics of Lipotactes (Mortoniellus) sanguineus

Description. Male and female habitus typical for subgenus, as in Fig. 2 . Head in frontal view with lateral margins below compound eyes straight and parallel, barely diverging or converging; suddenly constricting below fronto-cylpeal suture ( Fig. 3A ); head in female slightly less elongated than in male ( Fig. 3B ). Fastigium verticis in male not different from female, slightly elevated, faintly furrowed above gradually sloping laterally, distinctly inclined towards vertex ( Figs 3A–D ). Pronotal disc with anterior margin slightly emarginated and raised, bulging before and behind first sulcus, apical area up curved in both sexes ( Figs 3E, 3F ). Metazona distinctly longer than prozona in male ( Fig. 3E ), but of almost equal length in female ( Fig. 3F ). In male, apical area of metazona tapers into relatively narrow apex ( Fig. 3C ); in female, posterior margin somewhat truncated ( Fig. 3D ). Paranota triangular, with ventral margin straight ( Figs 3E, 3F ). Thoracic auditory spiracle of subequal size with first stigma ( Figs 3E, 3F ). Legs typical for genus. Male. Tegmen with dorsal field 5.1–5.5 mm long and 3.3–3.4 mm wide, veins and membrane mostly transparent except anal margin of mirror black; lateral field strongly folded and infumated ( Figs 4A, 4B ). h1 less wide than mirror width; h2 narrowly broad, mostly slender and substraight, with anal third to half widen broadly, anal margin somewhat truncated; mirror large and about as wide as long ( Figs 4A, 4B ). Stridulatory file of left tegmen on CuPb crescent shaped, ca. 1.29–1.41 mm long, with 46 teeth (with a few rounded indistinct teeth at both anal and basal ends) ( Figs 4C ); teeth length and inter-tooth distance largest at middle, decreasing in size towards both apices ( Fig. 5 ). Apical area of tegmen elongated, about 1.4–1.5 long, mostly infumated, narrow apically, apex rounded ( Figs 4A, 4B ). Tenth abdominal tergite with apical margin roundly incised in middle ( Figs 4D–F ). Epiproct large, tongue-shaped, apex rounded. Paraproct elongated, with apex rounded ( Fig. 4F ). Cercus conical, internal projections with dorsal lamellae medium-sized, inserted dorsad of ventral process; ventral process long, slender, blunt, curved dorsocraniad, inserted at end of circa basal quarter ( Figs 4D–F ). Subgenital plate faintly or strongly concave between bases of long styli, with narrow medio-longitudinal carinula ( Figs 4D–F ). Phallus with a pair of tooth-like sclerites, their apical half curved and tapering into acute apex, margins smooth ( Figs 4G, 4H ). Female. Tegmina and wings absent. Tenth tergite with apical margin faintly roundly-incised in middle ( Fig. 4I ). Epiproct somewhat triangular, at middle depressed, with apex rounded ( Fig. 4I ). Cerci conical, apex subacute ( Fig. 4I ). Subgenital plate triangular, slightly broader at base than length, with apex rounded ( Fig. 4J ). Ovipositor ( Fig. 4K ) with dorsal margin smooth, ventral margin finely serrulate in apical area ( Fig. 4L ). Colouration. Generally yellow to olive green (when alive, Fig. 6 ) or yellow (when preserved, Fig. 2 ), with black patterns on head, pronotum, thorax and legs. Frons between compound eyes with black. Antennal sockets, scapes, fastigium verticis and fastigium frontis also black ( Figs. 3A–D ). Margin around compound eye black, but more defined and complete in female ( Fig. 3F ). Maxillary and labial palpi with apical segments mostly black except basal quarter ( Figs 3A, 3B ). Mandibles black. Ventrad of gena on fronto-clypeal suture with black band, larger in female ( Fig. 3F ). Pronotum with margins black ( Figs 3C–F ); black band broader in female ( Fig. 3F ). Thorax with some black patches, more defined in female ( Figs 3E, 3F ). Coxa mostly black; ventral spurs mostly black; basal half of middle femur also black (expect ventrally). Hind femur only apical part dark coloured, including knees. Hind tibia with spines black. Tarsi dark. Abdomen ventrally bright to blood red ( Fig. 4J , 6 ). Measurements. See Table 1 . BL PL PW TL TW HFL HFW HTL OL ♂ holotype 14.0 7.3 5.3 5.5 3.4 14.4 3.8 12.6 - ♂ paratype 14.1 7.7 5.4 5.1 3.3 14.3 3.8 12.5 - ♀ paratype 15.8 5.4 5.5 - - 14.5 3.7 12.7 8.2 Calling song ( Fig. 7 ). The species was observed to call during daytime and not at night. The calling song is made up of a series of echemes. The echeme is made up of 9–16 syllables, and average of 13±2 syllables. The length of the echemes is probably affected by whether the katydid is disturbed. Depending on the number of syllables, the echeme duration ranges from 0.24– 0.55 s , and average of 0.41± 0.08 s . The down time between consecutive echemes can be variable, ranging from 0.38– 2.71 s , and average of 0.91± 0.59 s . Within each echeme, the first and second syllables are typically more variably and widely spaced apart, and the amplitude is lower than the subsequent syllables. Each syllable is made up of a series of pulses, and the average syllable duration is 18.4±2.2 ms (14.6–23.1 ms). The average down time between consecutive syllables is 10.2±1.6 ms (7.1–14.4 ms). When the katydid is not perturbed, the calling song can form an echeme-sequence made up of as many as 28 echemes. In such an echeme-sequence, the down time between consecutive echemes is much more consistent, 0.49±0.09 ms (0.38–0.74 ms). The initial echemes are generally shorter in duration and made up of fewer syllables) and are of lower amplitude. The call has a very broad band spectrum showing a broad energy peak between 8–22 kHz. The average peak frequency is 16.44±1.03 kHz (14.91–18.09 kHz). The calling song differs from that of ( Mortoniellus ) karnyi from Pahang (Peninsular Malaysia ) in the call structure. Lipotactes ( Mortoniellus ) karnyi produces long echemes (duration = 1.81± 0.07 s ) made up of 86–97 syllables; syllables duration (average = 13.0±0.2 ms) and down time between consecutive syllables (average = 7.1±0.5 ms) are also distinctly shorter. From other Bornean congenerics, the calling songs is similar to Lipotactes ( Lipotactes ) kabili Tan, Japir & Chung, 2020 from Sandakan in the similar call structure (i.e., echemes made up of only slightly more numbers of syllables: 9–16 vs. 3–15 syllables), but differs by distinctly shorter echeme duration (0.24–0.55 vs. 0.47– 2.35 s ) due to distinctly shorter syllable duration (14.6–23.1 vs. 125–199 ms) and distinctly lower peak frequency (16.4 vs. 28.7 kHz) and frequency spectrum (8–22 vs. >20 kHz). The species has similar call parameters as song type II of Lipotactes ( Lipotactes ) alienus Brunner von Wattenwyl, 1898 recorded from Brunei Darussalam , specifically in the echeme (0.24–0.55 vs. 0.18– 0.43 s ) and syllable (14.6– 23.1 vs. 18.1–21.9 ms) durations, but differs by the call structure with the initial syllables consistently more spaced apart than the subsequent syllables (instead of by consistent throughout the echeme) and a distinctly lower peak frequency (16.4 vs. 36.6 kHz).