Bioacoustics of Cardiodactylus singapura

Description. Size small for the species group. General coloration contrasted, light brown with dark brown patterns. Head dorsum yellow brown with 4 wide dark brown bands, more or less punctuated, bordered by dark brown triangles posterior to eyes and a yellow line more externally ( Figs 1 A, 2A). Fastigium mottled with dark brown. Scapes light brown with a transverse dark brown line anteriorly ( Figs 1 A, 2B). Antennae heterogeneously brown. Face yellowish to light brown, diversely mottled with brown, with 2 parallel lines on the fastigium, 4 dark spots on face, and 2 dark brown spots ventral to eyes. Mouthparts yellow brown. Maxillary palpi yellowish, dark brown apically. Head lateral side with a dark brown area posterior to eyes, progressively lighter ventrally. Pronotum: Dorsal disk trapezoidal, posterior margin straight or slightly bisinuated; light brown mottled with greyish brown and dark brown spots; anterior corners yellowish. Lateral lobes dark brown, ventral edges yellow. Legs light brown to yellowish brown, femora mottled with dark brown; tibiae more or less banded; tarsomeres with dark brown ends. Tarsomeres III-1 with 2–3 spines on dorso-external edges (m=2.2, n=10). Hind wings longer than FWs, the dark brown tail exceeding the forewings twice longer than the pronotum. Cerci light brown with black rings. Tergites light brown mottled with black. Male: FW coloration ( Figs 1 B, 2C): Dorsal field cells dark brown, veins mostly orange brown, except for whitish areas in the chords, part of anal veins and in the region posterior to mirror. Base of chords with a brown sclerotization. Harp posterior angle with a whitish sclerotized area. Lateral field dark brown; veins MA, MP, R orange brown, transverse veins and projections of R whitish. FW venation: 1A slightly bisinuated; stridulatory vein ( Figs 2 C, 2D) with 156–171 teeth ( Fig. 2 E) (m=164, n=4), distributed on both transverse (123–143 teeth, m=133) and longitudinal (15–20 teeth, m=19) parts of 1A, plus a group of 9–16 teeth near base of 1A (m=13, n=4). CuP missing. Harp longer than wide, with 2 w-shaped harp veins; posterior margin raised along diagonal vein. Mirror area variable, c1 long and narrow, c2 quite large; mirror (d1) longer than wide, not rounded, generally separated in two parts by a transverse vein, the posterior part triangular; e1 cell very elongated, along the mirror. Apical field long and triangular, with 3 wide cell alignments posterior to mirror and a narrow apical alignment. Lateral field: R with 6–7 projections (m=6, n=5). Subgenital plate yellow brown, the median area dark brown. Male genitalia ( Fig. 3 ): Pseudepiphallus very sclerotized, little setose, slightly narrowed at mid-length. Dorsal ridges parallel, forming a wide gutter, flattened anteriorly, their external edges carenated. Pseudepiphallic sclerite with latero-anterior expansions, but without a membranous sac as in C. novaeguineae ; membrane between the expansions with short strong setae. Apex of pseudepiphallus spoon-like, not rounded, and slightly indented. Rami narrow, with wide preapical plates. Pseudepiphallic parameres trilobate, the posterior lobe wide. Ectophallic arc complete, with a short posterior expansion. Ectophallic apodemes thin, divergent. Apex of ectophallic fold almost hidden by pseudepiphallic parameres, trilobate, membranous. Base of ectophallic apodemes with short sclerotized expansions oriented posteriorly. Endophallic sclerite small. Endophallic apodeme with both lateral lamellas and a short medio-dorsal crest. Membrane of endophallic cavity smooth. Female: FW coloration: cells dark brown, veins orange brown, with whitish sclerotization on distal half of CuA and MP, including cells between CuA and MA. MA and R orange brown, R bifurcations whitish. Anterior part of FW with variable number of whitish transverse veins. FW venation ( Fig. 4 A): 9–11 (m=10, n=5) strong longitudinal veins on dorsal field; lateral field with 9–11 (m=9.5, n=5) longitudinal veins including 5–6 R bifurcations and 3–4 ventral veins. Ovipositor: Shorter than hind femora; apex with both dorsal and ventral edges denticulate ( Fig. 4 E). Female genitalia ( Fig. 4 B–D): Copulatory papilla triangular with baso-lateral sclerotizations; apex rounded and folded ventrally. Juvenile: First instar after hatching observed in laboratory, similar in coloration to that of C. novaeguineae , yellow with brown longitudinal bands. Later instars with more contrasted coloration, body black, legs and head yellow brown ( Fig. 1 C–2C). Black coloration reverses in sub-adults, characterized by a more homogeneous brown coloration ( Fig. 1 C–D). Measurements. See Table 1 . PronL PronW FWL FWW HWT FIIIL FIIIW TIIIL Male holotype 2.4 4 14.1 4.3 4.2 14 3.7 11.5 Males (n=5) 2.2–2.4 3.7–4.2 13.3–14.1 4.1–4.3 4.2–5.4 13.4–15 3.6–4.1 11.5–13.1 (Mean) (2.4) (4) (13.7) (4.2) (4.9) (14.3) (3.9) (12.5) Female allotype 2.5 4.3 14.5 4.2 5.5 15.5 3.9 13.4 Females (n=5) 2.2–2.7 4.1–4.5 13.5–15.2 3.9–4.4 4.5–5.5 14.1–15.5 3.9–4.4 12.5–13.5 (Mean) (2.4 (4.3) (14.3) (4.1) (5.1) (14.9) (4.1) (13) continued. TIIIs TaIIIs ST OL Ias Ibs Oas Obs Tt Lt Bt Male holotype 8 6 11 7 3??? - Males (n=5) 8–10 6 11 – 13 7 2–3 - (Mean) (8.8) (6) (11.8) (7) 2.2 - Female allotype 6 6 11 7 3 - - - 10.9 Females (n=5) 6–10 6–7 11 – 13 5–7 2–3 - - - 9.7–10.9 (Mean) (8) (6.4) (11.8) (6.4) (2.2) - - - (10.2) Habitat and life history traits. Cardiodactylus singapura is a nocturnal species living in the forested areas. Males produce their discreet calling songs at night, from low branches and leaves ( Fig. 1 ). Juveniles are found day and night in the leaf litter and on leaves of low plants. Behavior. Calling song ( Fig. 5 ): High speed video observations at 1250 frames per second confirm that each calling song corresponds to only one FW closure, the gaps within the syllable being made by the jerking movement of the FWs. At 26°C, this mono-syllabic calling song (TR-male1-F0male: MNHN-ENSIF2754) lasts for 87.0 ± 11.8 ms with a period of 8.2 ± 2.2 s and a duty cycle of 1.06%. The dominant frequency is 19.0 ± 0.7 kHz and corresponds to the third frequency peak of the song.