Bioacoustics of Platycleis albopunctata

( Fig. 1 , 2 , 3 and 4 a, b ), ( Table 1 ) Tettigonia albopunctatus Goeze. 1778 . Entomologische Beyträge zu des Ritter Linné zwölften Ausgabe des Natursystems 2:89. Chelidoptera albopunctata Kirby, W. F. 1906 . A Synonymic Catalogue of Orthoptera ( Orthoptera Saltatoria , Locustidae vel Acridiidae ) 2:203. Metrioptera albopunctata Caudell. 1908 . Genera Insectorum 72:31. Platycleis albopunctata Kaltenbach. 1963 . Ann. Naturhist. Mus . Wien 67:439-442. Platycleis albopunctata Bellmann. 1985 . Heuschrecken: beobachten, bestimmen 100. Redescription. Body medium to large in size, light brown in colour; fastigium of vertex broad and convex, surpassing the base of antenna and is almost two times wider than scapus of antenna; eyes large, bulging outwards and centrally blackened; pronotum depressed dorsally with a median keel or carina at metazona, anterior and posterior margin rounded; lateral lobes of pronotum higher than long, with distinct humeral sinus; prosternal process rudimentary; mesosternum divided at the middle by a deep V- shaped incision into two triangular lobes; metasternum bifurcated medially with shallow grove, lateral margin of basal lobes rounded, apical lobes angularly rounded apex; tegmina and wings not surpassing the tip of ovipositor when straightened; mirror almost oval shaped, stridulatory file slightly curved with 67 teeth which are evenly arranged, middle teeth are large and gradually decreasing in length at both the proximal and distal end; file gradually narrow at distal end; tibia dorsally sulcate; fore coxae armed by an incurved spine; all femora dorsally unarmed; fore and mid femora ventrally unarmed; hind femora ventrally armed by a single sub-basal spine on inner margin; 4 small, thick black colored spines arranged on outer margin; tympanum present on fore tibia; fore tibia usually armed with 3 spines dorsally on outer margin, ventrally armed with 6 spines on inner and outer margin; hind tibia dorsally armed with 26 spines on inner margin and 29 spines on outer margin; single dorsal pair of spurs and two ventral pairs (inner smaller and outer larger) present; tenth abdominal tergite cut medially with deep V- shaped incision. Male genitalia: Supra-anal plate triangular with obtusely angular apex; subgenital plate longer than broad, apical margin with small median triangular incision; styles conical and moderate-sized; the anal tergite with a median shallow depression; cerci thick basally with blunt ends, internal tooth short with incurved spine at the middle. Female genitalia: Tenth abdominal tergite cut medially with shallow depression; supra anal plate triangular, medially grooved with obtusely angular apex; subgenital plate broader than long, with shallow rounded incision into lobes with rounded apex; cerci conical, straight, thick and gradually thin at subapical end; ovipositor thick, sword shaped, regularly curved, surpassing the hind femur when straightened.

In warm sunshine the calling song consists of long sequences of echemes repeated fairly regularly at the rate of about 2-4/s and each usually consisting of 3-5 (very rarely 2 and occassionally 6) syllables. Oscillographic analysis shows that opening hemisyllables are often absent and that the closing hemisyllables usually last about 10-30 ms and are repeated within an echeme at the rate of about 25-35/s. The duration of a single echeme of four syllables is about 100-200 ms and the interval between two echemes is about 100-300 ms. In dull weather and at night the echeme repetition rate can drop to less than 1/s and the syllable repetetion rate to less than 10/s; in such conditions the closing hemisyllable sometimes lasts more than 100 ms and a four-syllable echeme more than 600 ms. The first syllable in an echeme is usually quieter than the remaining ones. Microsyllables are usually absent, but occassionally a few are added at the end of an echeme, especially the opening echeme of a sequence (see Figs 261, 267, 2730.

The song consists of a brief chirp, repeated at a. rate of 2 to 4 times per second, and continued in prolonged bursts lasting several minutes. The sound is rather quiet, and often obscured by the sound of the wind in its exposed habitat. However, when picked up with the aid of a bat detector it is quite distinctive. Males do not congregate, as males of the dark bush-cricket do, but 'duets' can often be heard when the osng of one male interacts with that of another. However, in laboratory experiments such alternating duets have been shown to break down after some time, and the interaction may simply function to enable the males to space themselve sout across the availbale habitat (Latimer, 1981a, 1981b).