Bioacoustics of Trichophallus capillatus

Comments. The file of T. capillatus ( Fig. 68 ). Stridulation. Call a regular repetition of silence-separated trains of rapid-decay, single-tooth sourced, transient pulses ( Fig. 69 AB). The call manifests spectrally as a 25-kHz wide band of frequencies ( Fig. 69C ) centred near 48 kHz. The carrier frequency of this insect is entirely confined to the ultrasonic; there is no significant sound energy in the audio range. At the time resolution of Fig. 69A each train has a characteristically ‘top shaped’ amplitudeenvelope (a shape like a toy top lying on its side): pulse peak amplitudes begin very faintly, rise steadily then fall away again slightly over the last third. Stridulatory file count of 88–93 teeth reported by Ingrisch (2024) accords reasonably with the 68 transient rapid-decay pulses in the train shown in Fig. 69B . Mean values for 10 calls of our lone singer: trains 30 ms long, repeated with a mean period of 168 ms. The transients are somewhat erratically separated in time from each other within the train ( Fig. 69B ). Broadband spectra should not be discounted as noisy stridulatory incompetence. Bands could theoretically be adaptive through ranging: differential attenuation of frequencies with distance is accentuated by a cluttered vegetation. The spectral shape of the band could be coding for distance, so helping to detect the trespass of a neighbouring male competitor or further the success of a female localizing her mate ( Morris et al . 2016 ).

Description. Small species. Tegmina varying from just surpassing hind knees to reaching middle of hind tibia, rarely surpassing middle of hind tibia. Femora with the following number of spines on ventral margins: fore femur 2–7 very minute external, 2–6 internal; mid femur 5–7 external, 1–4 internal near base; hind femur 7–12 external, 0–11 minute internal (1 or 2 near apex can be larger). Male. Stridulatory file on underside of left tegmen 1.36 mm long, with about 88–93 teeth, with about the last 20–29 teeth becoming very small and narrow towards end of file. Tenth abdominal tergite terminating into two short triangular lobes, apex wide roundly excised in between. Epiproct with parallel lateral margins, apex truncate or slightly convex, ventral surface greatly swollen, dorsal surface with a deep pit at base. Paraprocts with internal margin greatly swollen. Cerci rather short and stout, slightly curved behind base otherwise almost straight, apex obtuse; with a conical, internal projection before middle which has a sharp tooth at tip. Subgenital plate roundly excised at apex; styli thin, little longer than excised area or of about equal length. Titillators separate, basal area strongly sclerotised, darkened, with internal surface slightly concave, curved around mid-length and with apical margin obliquely truncate; apical area hyaline, inflated, sub-membranous, might be movable against basal area; that area at end divided into an area with granular surface on ventral-lateral side and a ballon like, simply hyaline area on dorsal-proximal side that gives rise to a cone on proximal side; internal surface of membranous area over whole length with a straight row of long bristles surpassing end of hyaline area. Titillators of holotype separate, basal area strongly sclerotised, darkened, elongate, band-shaped with internal surface slightly concave, curved around mid-length and with apical margin obliquely truncate but somewhat irregular; apical area hyaline, inflated, sub-membranous, with granular surface, and obviously movable against basal area; at end on both sides with an oval sclerotised small sack with granular surface and stiffened rim with fine spinules; from the membranous subapical area on both sides with a row of long bristles. Female. Tenth abdominal tergite divided in midline. Subgenital plate with a short entire basal area with concave surface, apical margin of entire area carinate with carina interrupted in midline and laterally curved into the ventral margin of moderately long, narrow and almost straight but converging apical lobes; apex of entire central area behind carina extended dorsad and with concave surface that is continued into the internal surface of the apical lobes, giving the lobes a spoon-shaped appearance in oblique ventral view; ascending lateral areas with concave surface that is interrupted by a longitudinal carina, with swollen apical and especially dorsal margins, and with a bulging lobe at anterior margin that is little covering the concave surface. Ovipositor with dorsal margin of ventral valves with an oblique, conical, setose projection, and ventral margin between apical lobes of subgenital plate swollen and also setose. Eight abdominal tergite with lateral-posterior area excised providing a triangular space between eight and ninth tergite in which the lateral area of the subgenital plate protrudes. Subgenital plate with lateral area deeply grooved, divided in middle by a carina which is fused with dorsal margin; dorsal margin swollen. Coloration. Nearly uniformly yellowish brown with patterns 1–4 but very faint or with patterns 1 and 3 faintly indicated. Measurements ( 26 males , 17 females ).—body w/o wings: male 15–21 (17.9±1.3), female 14–23 (18.3±2); pronotum: male 4.2–5.0 (4.6±0.2), female 4.1–5.0 (4.6±0.3); tegmen: male 16.5–24 (20.1±2), female 17.5–27.0 (20.9±2.4); hind femur: male 10.5–13.5 (12±0.8), female 11.5–14.5 (12.5±0.9); antenna: male 50–60 (53.3±5.8), female 60; ovipositor: female 8.5–10.2 (9.2±0.5) mm. Etymology.—The name of the new species refers to the group of hairs on top of the titillators.