Bioacoustics of Eurycorypha spicula

Description . — Male. Habitus and color. A roundish medium-sized species, green with lighter veins on the tegmina and speckled with white dots and patches on pronotum and head (Fig. 2 A ). Color pattern white to yellowish veins on dark green background on the tegmina, rest of body also speckled yellowish-green. Head and antennae: Antennae typical of Eurycorypha , thin, about as long as flexed tegmina. Fastigium verticis about 2.4 times as wide as scapus of antenna; fastigium verticis meeting equally broad fastigium frontis along a well-developed horizontal line; face with callose frontogenal carinae, yellow when alive; eyes typical for Eurycorypha , elongate and oval. When alive, with yellow fasciae. Thorax: Pronotum with flat and smooth disc, anterior margin of pronotum broadly incurved, posterior margin broadly rounded. Wings: Tegmina roundish, only about 2.5 times longer than broad; alae only slightly protruding. Stridulatory file comparatively long, evenly curved, and about 2.2 mm long, consisting of very densely packed teeth. Legs: Fore coxa with very short, broad-based spine. Fore and mid femora dorsally unarmed, ventrally with 2–4 spines on outer side and without inner spines. Hind femora ventrally with 4 spines at apical end. Fore and mid tibiae with ventral double row of few spines (3–8). Hind tibiae with 4 rows of spines and three spurs at each side. Abdomen: Last abdominal tergite with two broad-based short spines at posterior margin (Fig. 3 A ). Cerci thick at base, narrowing to their apices and ending in a sclerotized small ridge (Fig. 3 A, C, E ). Subgenital plate with broad base. Posterior margin incised forming two short processes with small styli (Fig. 3 C ). Female. — Very roundish and compact, of same color pattern as male (Fig. 1 B ). Ovipositor well-developed, upcurved (Fig. 3 B ). Subgenital plate forming a triangular flap. Lateral margins of the lower valves are thickened, running in parallel to the subgenital plate and forming an ear-like grove or hole lateral at base of pronotum (Fig. 3 B, D, F ). Nymphs. — The first stages resemble black ants, gaining more color in stages two and three (Fig. 2 C, E ). Unlike most other Eurycorypha species where nymphal stages are known, the nymphs of E. spicula are dorsally black on the head, the pronotum, and the abdomen, and the legs are partly black. The black coloration persists in the last two stages four and five (Fig. 2 F ) and vanishes when molting to the adult, which is predominantly green (Fig. 2 A, B ). Eight nymphs (L 1 – L 3) were collected in November 2024 at the same locality as in 2021, suggesting that this species hatches in November, coinciding with the onset of the short rains and rising temperatures.

Bioacoustics . — The male song consists of complicated and quite characteristic echemes. One relatively long syllable is followed by a series of shorter elements (Figs 8 B , 9 B ). Surprisingly, some parameters of these echemes were quite variable in the three recorded males. The duration of the long syllables varied between 38.4 and 84.4 ms, the number of short syllables ranged between 6.8 and 11.8, and variation of the duration of the complete echeme was also not small (324–441 ms; all means of 3 males ; n = 10 per male; T = 21 ° C). More constant were the periods between the beginning of the long syllable and that of the series of short syllables (138–152 ms) and between the short syllables (28.5–31 ms corresponding to 32–35 Hz SRR; measured from the beginning of the 5 th to that of the 6 th syllable). The echemes were repeated at intervals of several seconds. When two males were singing in acoustical contact, the structure of their echemes became more irregular (‘ leader’ in Fig. 10 A, B ; upper line), while the other (‘ follower’ in Fig. 10 ; lower line) placed his echemes immediately after that of the first. Occasionally the leader also produced long series of short syllables. The first answer of females was recorded approximately 417 ± 27 ms (mean ± SD; n = 10) after the beginning of the echeme, 281 ± 27 ms after the beginning of the syllable series, and 76.5 ± 30 ms after the end. However, in other situations (e. g., when several males were singing), the females responded more variable with latencies of the first response very close to the end of the male echeme (0.6 ± 50.1 ms – 2.6 ± 35.6 ms). The amplitude modulation of their response was also very variable, from single impulses (Fig. 9 B ) to series of impulses, probably produced by repeated tegmen movements (Fig. 9 C ). If they were not answers to their own songs, males reacted to these sounds, sometimes by producing a series of short syllables (Fig. 9 C ). See the discussion for the function of the parts of the song. The spectrum of the male song showed a broad peak around 13 kHz; that of the female was similar but even broader (Fig. 11 ; see Table 1 for other details). Male stridulatory file, tooth number, and inter-tooth intervals are in the range typical for Eurycorypha (Table 1 ; for comparison, see Heller and Hemp 2020 ).