**3.2.1** *Rhammatocerus pictus*

Calling song was a spontaneous song, consisting of echemes composed of a variable number of syllables (Table 4).

Its frequency spectrum occupied a broad band, with the peak of maximum amplitude at around 7 kHz (Table 4, Fig. 4C).

The echeme started with short and almost inaudible syllables. The sound increased in intensity after 1/3 of the echeme had been emitted. Syllables were clearly separated one from other by evident gaps (Figs. 4A and B).

It was produced by synchronously rubbing the two hind femora against the tegminae, both hind legs moving rapidly. At the beginning of the echeme the legs movement was hardly visible.

Courtship songs were composed of echemes of a variable number of syllables (Table 4). Two different types of song have been observed, the here called pictus 1 (Fig. 4D-F) emitted at a

Fig. 2. Results of PCA performed to explore relationships among types of sound considering all the variables used: 1 echeme length; 2 number of syllables; 3 syllables length; 4 rate of emission of syllables; 5 peak of maximum amplitude; 6 low quartile; 7 middle quartile; 8 maximum frequency; 9 minimum frequency; 10 upper quartile;

Calling song was a spontaneous song, consisting of echemes composed of a variable number

Its frequency spectrum occupied a broad band, with the peak of maximum amplitude at

The echeme started with short and almost inaudible syllables. The sound increased in intensity after 1/3 of the echeme had been emitted. Syllables were clearly separated one

It was produced by synchronously rubbing the two hind femora against the tegminae, both hind legs moving rapidly. At the beginning of the echeme the legs movement was hardly

Courtship songs were composed of echemes of a variable number of syllables (Table 4). Two different types of song have been observed, the here called pictus 1 (Fig. 4D-F) emitted at a

11 bandwith

visible.

**3.2.1** *Rhammatocerus pictus* 

around 7 kHz (Table 4, Fig. 4C).

from other by evident gaps (Figs. 4A and B).

of syllables (Table 4).

broad band, with the maximum amplitude at around 5 kHz, and the called pictus 2 (Fig. 4G-I) which occupied a much narrower band, with the maximum amplitude at around 2 kHz; both are significantly different (Fig. 3).

Fig. 3. Graphic showing the results of plotting scores for each cases against components 1 and 2 of PCA.

When the courtship started, the male moved walking towards the female; stopping when close and perpendicular to her. Then he moved his antennae up and down, synchronously at the beginning and, then, alternately, and started to sing. While singing, he directed his antennae towards the female, forming an around 150º angle. After the song, the male usually jumped suddenly on the female, trying to mate while touching her with his antennae. In most cases, the mating was not effective, the male being rudely rejected by the female by kicking the male, raising the hind legs or simply going away him.

While the courtship song, males performed two kinds of movement: 1) Mute movement: one to three slow and wide up and down movements of hind legs. They rose synchronously from the rest position (around 30º in relation to the main corporal axis) to around 75º, and then bent slightly asynchronously. 2). Stridulatory movement: a series of synchronous, quick and small up and down movements, of little amplitude (30-55º) respect to the corporal axis. In some cases, the movement 1 lacked, the courtship starting directly with the quick movement.

The Acoustic Behaviour as a Tool for Biodiversity and Phylogenetic Studies: Case of

the *Rhammatocerus* Species Inhabiting Uruguay (Orthoptera, Acrididae, Gomphocerinae) 59

Fig. 4. *Rhammatocerus pictus*. Calling (A-C) and courtship (pictus 1 D-E and pictus 2 G-I) songs. Echeme (A, D and G); syllable detail (B, E and H), and frequency spectra (C, F and I).

Fig. 5. *Rhammatocerus brunneri.* Calling song (A-C) and courtship song (D-F). Echeme (A and

D); syllable detail (B and E) and frequency spectra (C and F).

The songs started as imperceptible, almost inaudible, and sound increased in intensity until the end. At the final section, syllables were intense, similar in structure, with gaps between them (Fig. 4 D-E and G-H).

The MANOVA run separately for the group 2 identified by the PCA revealed that for this species, overall, calling song and pictus 1 courtship song were not significantly different (F11, 3= 0.702; P= 0.712), existing differences only in the case of some the response variables dealing with frequency (P≤0.037): peak maximum amplitude (F1, 13= 5.401; P= 0.037), low quartile (F1, 13= 11.494; P= 0.005), upper quartile (F1, 13= 6.026; P= 0.029), middle quartile (F1, 13=7.279; P= 0.018) and minimum frequency (F1, 13=11.527; P= 0.005).
