Lissotrachelus ferrugineonotatus, Brunner von Wattenwyl, 1893

He, Zhu-Qing & Shen, Chu-Ze, 2020, First record of Lissotrachelus ferrugineonotatus cricket producing ultrasound (Orthoptera: Grylloidea), Zootaxa 4768 (3), pp. 443-445 : 444

Lissotrachelus ferrugineonotatus

are small crickets in 6-8mm ( Fig. 1 A–B; Chopard 1969; Yin & Liu, 1995). Living L. ferrugineonotatus crickets were collected from Ruili, Yunnan. Four males and five females were kept in a plastic box with small holes (diameter: 20 mm, height: 50 mm) in the laboratory in temperature 25 degree. UltraSoundGate 116 (linked with computer) were used to recorded their songs near the box at 1600 kbps/36000 Hz sample rate. Songs were replayed for analysis using Cool Edit software. To observe the teeth structures on forewings, we removed and placed them in 100% ethyl alcohol. Prior to SEM observation, samples were placed in a Quorum K850 critical point dryer (Quorum, UK) to be desiccated, and then placed on conductive tape and coated with platinum. Observations were conducted with a Hitachi E-1010 scanning electron microscope at 10kV and the figures were also taken by the same instrument.

The male was observed singing without moving or chasing females. We considered it as the calling songs rather than courtship sounds, though females were nearby. Although our ears could not hear their songs, three records of songs were detected by the device ( Fig. 2 ). Songs consisted of stereotyped chirps with almost no variation. The rate of chirps was 5.85 N /s. Each chirp contained two pulses (only one chirps in three songs having three pulses as in Fig. 2B ). Two pulses had 0.0279± 0.0007s interval. The frequency peak was 25.65±0.09 kHz ( Fig. 2-A2, B2, C2 , D). Different to the songs of Eneopterinae crickets having several peaks, only one frequency peak showed in frequency spectra and no other peak was detected in range 0-36 kHz.

Both forewings had teeth. The teeth on right forewing were larger than those on left forewing. Teeth on left forewing were closer together with each other (1.25 N / 5 μm), while teeth on right forewing were not so close (1 N / 5 μm). Total 109 similar teeth arranged with except for a few teeth at either end on right forewing ( Fig. 1C ). Each tooth was thin in shape with sharp edged. These features were most similar to that found in Trigonidiinae or Nemobiinae . There is no phylogenetic study including genus Lissotrachelus or Lissotrachelini until now. Brunner von Wattenwyl (1893) established genus Lissotrachelus with 3 new species and considered it belonging to the ant crickets, Myrmecophilidae . Kirby (1906) followed this classification, but treated Myrmecophilidae as Myrmecophilinae . Chopard (1969) placing it in the Pentacentridae bsased on “the shape of the head with sloping forehead and antennae inserted beneath the middle of the face”. Yin & Liu (1995) considered it in the Lissotrachelinae in the Trigonidiidae . Based on the shape of forewing teeth, we consider this genus belongs to family Trigonidiidae . That the second joint of tarsi flattened suggests L. ferrugineonotatus may belong to Nemobiinae . These inferences should be tested by molecular phylogenetic studies in the future.

Figures

FIGURE 1 Lissotrachelus ferrugineonotatus: A, male; B, female; C, teeth of right forewing (scale bar = 100 μm); D, teeth of right forewing (scale bar = 5 μm); E, teeth of left forewing (scale bar = 5 μm)

FIGURE 2 Characters of songs: A, B, C, waveform of three record of songs; D, frequency spectra.