Metaleptea adspersa (Blanchard, 1843)

Songs
The typical rivalry song consisted of individual syllables comprised mainly of 4 single or multiple pulses (range 2-7) (Figs. la, lb). The rivalry songs in the presence of conspecifics seemed similar to those in the presence of other species; however, the length of syllables was 0.197 s (range 0.055-0.295) when the song was the result of an interaction with conspecific male (n = 51) compared with 0.322 s (range 0.200-0.430) when the song was the result of an interaction with other species (n = 90). The main frequency spectrum showed a broadband between 5 and 16 kHz, with the main peak around 11 kHz. Fifty percent of the total energy was located around 11 kHz, and lower (25%) and upper (75%) quartiles were around 8.5 and 13 kHz, respectively (Fig. lc). The intensity of the sound was low.

The copulation song was composed of a series (Fig. 2a) that vary in length. They can last from 7.40 to 41.20 s (mean duration 19.66 s; n = 5) and are composed of 3-21 syllables (mean = 10 syllables; n = 5), which last a mean of 0.363 s (range 0.225-0.513; n = 50). They are emitted at a rate of 0.5 syllables/s (range 0.405-0.598 syllablesls). These syllables were composed of 4-6 single, double, or even more complex pulses (Figs. 2b, 2c). The lapse between syllables was uniform, lasting about 1.5-2 s (n = 50). The main frequency spectrum showed a broadband between 4 and 16 kHz, with the main peak around 7 kHz (Fig. 24. Fifty percent of total energy was located around 8 kHz, and lower (25%) and upper (75%) quartiles were around 6 and 12 kHz, respec- tively. This sound was as low as the rivalry song.

Field observations revealed that copulation occurred on tall grasses [e.g., Paspalurn dilatatum Poiret (Poaceae)] where the individuals live. During copulation, which lasted 2-4 h, males and females remained motionless. The sound was produced in spontane- ous series, without being provoked by either any other specimens or unusual activity of the copulating female. The songs, emitted almost continuously (about 12 series110 min; n = 10) during copulation, were interspersed only with brief pauses (7 s to 3 min). There was no apparent movement by the male during sound production.

The crepitation song was composed of pulses of variable intensity (generally low) that were emitted irregularly (Fig. 3b). Sometimes the sound appeared composed of pulses distributed regularly during the entire song. (Fig. 3a). The whole song duration varied from 0.261 to 1.217 s (n = 1 I), with a mean value of 0.757 s. Longer songs ap- peared to be composed of two parts: the first one was irregular and the most intense, whereas the second one was more regular and weaker (Fig. 3b). The structure of shorter songs appeared similar to that of the first part of longer songs (Fig. 3a). Pulses were ei- ther single or multiple (Figs. 3c, 34. The main frequency spectrum also showed a broadband between 3 and 16 kHz, with the main peak around 5 kHz (Fig. 3e). Fifty percent of total energy was located around 6.5 kHz, and lower (25%) and upper (75%) quartiles were around 4 and 9.5 kHz, respectively.

Sound production structures
Sounds were produced by the tegmen and hind wing of males. The fore margin of male tegmen (Fig. 4a) is slightly bent downward, fitting with the enlarged area of the hind wing. The inner surface of the tegmen shows the subcostal and radial veins thick- ened all along the two basal thirds. When resting, these veins are in contact (or almost in contact) with the enlarged veins of the hind wing.

In the fore margin of the male hind wing (Fig. 4b) there is a slightly expanded, enlarged, and sclerotisated area, involving the subcostal, radial, medial, and cubital 1 veins, appearing as keels. The vein cubital 1 is short, and it is apparently fused to the medial and radial veins to form a thick rib. For males, the cubital area, located between the cubital 1 and cubital 2 veins, is wide and consists of elongated cells. Females lack these modifications, having a typical hind wing (Fig. 5). [1]

Références