Bioacoustics of Duolandrevus (Eulandrevus) kawataredoki

Description. Fairly small and stout cricket: cylindrical, slightly dorso-ventrally compressed and fairly pubescent ( Fig. 3 ). Head rostrum distinctly wider than scapus, with apex truncated (in dorsal view) ( Fig. 4A ). Maxillary palpi with apical (fifth) segment elongated triangular, distinctly larger, broader, and longer than third and fourth segments, with apex swollen and obtusely rounded; subapical (fourth) segment slightly shorter than third segment ( Fig. 4B ). Pronotum transverse; dorsal disc gently widens posteriorly, slightly wider at the posterior end than long; anterior and posterior margins with strong hairs; disc with anterior and posterior margins straight ( Fig. 4A ); lateral lobe longer than tall; ventral margin of lateral lobe slightly concave in the middle ( Fig. 4B ). Fore tibia with small and rounded inner and outer tympana. Hind tibia inner and outer margins with 4 stout articulated spurs (also known as movable spines) on each dorsal side; and 2–3 much smaller basal spines; inner margin with two long apical spurs, outer margin with one shorter apical spur (still longer than subapical spurs. Hind basitarsus with 4 inner and 4 outer denticles. Tegmen not pubescent, extending to middle of 6th abdominal tergite ( Figs. 3 , 4B ); dorsal field with mirror oblong (longer than broad) and not separated by a vein, two cord veins, and eight harp veins (three anterior ones are small); anal area truncated; lateral field with five longitudinal veins ( Fig. 4C ). Hind wings absent. Metanotal gland transverse, with two small oval depressions nearly separated in the middle; anterior margin feebly concave with long and strong hairs; posterior margin deeply concave in the middle ( Fig. 4D ). Ninth abdominal tergite transverse, posterior margin slightly convex in the middle ( Fig. 4E ). Anal plate (fusion of tenth abdominal tergite and epiproct) broad at basal half (wider than entire length), tapering to a slightly narrower apical half (about as wide as entire length, and wider than length of apical half); apex truncated with a few setae ( Fig. 4E ). Subgenital plate slightly broader than long, tapering gently into a rounded apex ( Fig. 4F ). Male genitalia as shown in Figs. 4G–J . Male epiphallus deeply and fairly widely notched, not distinctly folded transversely (when viewed dorsally) ( Fig. 4G ). Posteromedial epiphallic lobules (when viewed dorsally) directed posteriorly, slightly curved internally, and with almost acute apex; narrowly notched between the lobules ( Fig. 4J ). Posterolateral epiphallic lobe (when viewed dorsally) elongated and straight, pointing posteriorly and slightly towards each other, apex subacute, with internal process before posterior third of the lobe ( Fig. 4G ); (when viewed laterally) roundly tapering into a narrowly truncated apex, without roundly angular dorsal projection ( Fig. 4I ). Internal process of posterolateral epiphallic lobe points anteriorly with obtuse apex; not touching, overlapping, or fusing with each other; but nearly touching the posteromedial epiphallic lobules (when viewed dorsally) ( Fig. 4G ); elongated rounded (when viewed laterally) ( Fig. 4I ). Principal apodeme widely forked posteriorly. Formula very short and stout, posterior apex broad (when viewed dorsally) ( Fig. 4G ). Ramus not fusing together at the anterior end, with flattened and slightly membranous exterior plate near posterior third ( Fig. 4G ). Coloration. Generally red brown or brown. Head red brown; antenna scapus and antennal segments lighter brown. Gena red brown; clypeus maxillary palpi yellow brown with apical end of each segment white. Pronotum red brown. Tegmen red brown, but ventral half of lateral field transparent. Legs generally red brown, tibiae more of yellow brown. Hind femur mostly red brown, except ventro-internal area white; hind tibia generally red brown, dorsally dark brown apical of knee; spines on hind tibia red brown with black tips; hind tarsus brown; spines on hind tibia and tarsus brown with black tips. Thoracic segments white. Abdominal tergites and sternites (including subgenital plate) red brown; anal plate dark brown. Female ( Fig. 5 ). Cylindrical, similar to male ( Fig. 5A ). Wingless ( Fig. 5B ). Metanotal gland absent ( Fig. 5B ). Ninth abdominal tergite transverse ( Fig. 5C ). Anal plate trapezoid, about as long as broad, flattened, tapering into a truncated apex; posterior margin with hairs ( Fig. 5C ). Subgenital plate also trapezoid broader than long, apex fairly narrow and truncated ( Fig. 5D ). Ovipositor relatively long, surpassing middle of hind tibia and nearly reaching apical spurs; slender, feebly thicken towards apical valves; dorsal valves slightly longer than ventral valves; valves with margin smooth and with apices acute (especially so for the dorsal valves) ( Fig. 5E ). Measurements (in mm). Male BL = 11.0–12.2; HL = 2.2–2.3; PL = 2.7–2.8; PW = 3.1–3.5; TL = 6.7–5.8; HFL = 8.1–8.4; HTL = 5.2–5.3. Female BL = 12.4; HL = 2.4; PL = 3.0; PW = 3.6; HFL = 9.1; HTL = 5.7; OL = 6.5. Male calling song ( Fig. 6 ). The male produces trilling calls of various length (between less than 1 sec to slightly more than 2 sec). The calling song has a mean frequency of 5.0 kHz; mean dominant frequency of 4.6 kHz, maximum dominant frequency of 5.9 kHz, minimum dominant frequency of 3.2. kHz. Each thrill gets louder before plateauing; dominant frequency also increased from 3.8 kHz to 4.9 kHz.