Eurycorypha pianofortis, Hemp, 2017

Heller, Klaus-Gerhard & Hemp, Claudia, 2020, Hyperdiverse songs, duetting, and the roles of intra- and intersexual selection in the acoustic communication of the genus Eurycorypha (Orthoptera: Tettigonioidea, Phaneropterinae), Organisms Diversity & Evolution (New York, N. Y.) 20 (4), pp. 597-617 : 607-608

Eurycorypha pianofortis ( Figs. 3 , 4b , 5 , 6 , 8c , and 10 )

The species has an unusually complex song, containing different types of echemes ( Figs. 4b and 8c ). One of these types was much louder than the others. The species name refers to this difference in intensity (pianofortis = quiet loud). The structure of the loud echeme was relatively simple, a group of three to five syllables produced with a rate of 18 Hz (syllable period 55 ± 9 ms, syllable duration 25 ± 3 ms; n = 7 from 7 different males). These echemes were presented isolated or in small groups (2–4) with intra-group intervals of a few seconds. Before the syllable group regularly a few isolated impulses were observed appearing as a strongly reduced syllable. The other echeme types in the surrounding of the loud echemes (length of sound files 30–450 s, mean 171 s) were 12 dB softer (mean; range, 6.7–16.7 dB; Fig. 8c ). One of these echeme types is very similar to the loud one (SRR, 18 Hz; syllable period, 56 ± 4 ms; syllable duration, 34 ± 4 ms; n = 8 from 8 different males), but much softer. It was often found in the proximity of loud echemes and could even be produced in alternation. Both types were never answered by females. The third type contained much more syllables, clustered in one group followed by one isolated syllable. Sometimes a more or less smooth transition from the second type occurred by adding groups of syllables of increasing numbers ( Fig. 10a ). This echeme type ( Fig. 5 ) contained 13.7 ± 3.4 (8 males; 5 measurements per male) syllables. Within the echeme, the syllable repetition rate increased slightly from 18 to 25 Hz (measured in the third period from beginning respectively end; 53.8 ± 7.4 to 39.5 ± 5.1 ms) with decreasing syllable duration (31.0 ± 6.6 to 22.3 ± 3.1 ms). The isolated syllable was produced after a quite variable gap of 399 ± 101 ms but was relatively constant in reference to the beginning of the echeme (1024 ± 90 ms).

The acoustical response of the female was registered 126 ± 27 ms (3 females; 5 measurements per female) after the beginning of the isolated syllable in the male echeme ( Fig. 6 ). It consisted of one to several loud impulses and often of some soft additional ones. Occasionally, the female produced a few isolated impulses after the main response (within the next 500 ms). If a male had heard the response it often modified its song by adding one or rarely several single syllables after the isolated syllable of the echeme. Sometimes, it made also a series of soft impulses between these syllables ( Fig. 10b ).

Figures

Fig. 3 Power spectra of male calling song of Eurycorypha species. In species with restricted frequency range, short black lines mark its end. Blue lines indicate power spectra of female responses

Fig. 4 a, b Oscillograms of male calling songs, overview (10 s sections)

Fig. 5 Oscillograms of male calling songs, details (1.5 s sections)

Fig. 6 Oscillograms of male- female duets, overview (10 s sections)

Fig. 8 Oscillograms of long acoustical (1 min sections) interactions of a males in Eurycorypha curviflava and duets of males and females in b E. ligata, c E. pianofortis, and d E. pseudovaria

Fig. 10 Oscillograms of song interactions in Eurycorypha pianofortis.a Male song demonstrating the transition between two echeme types.b Male-female duet