Acridium declivus Brisout de Barneville, 1848: 2 (6), 420.
Distribution in the Palaearctic region: South Western and Eastern Europe, Balkans, Turkey (Willemse 1985; Mol & Zeybekoğlu 2013).
Distribution in the Turkish Thrace: First record for the study area.
Material examined: KIRKLARELİ: Kırklareli-Kofçaz road, 514m a.s.l., N: 41°54.430’ E: 27°10.714’, 31.VII.2013, 14 ♂♂, 11 ♀♀, leg.: D. Şirin & E. Bayram (Fig. 11 A). Calling song recorded from two males at 27 ˚C in the laboratory conditions by D. Şirin.
Description of song: Euchorthippus declivus male calling songs usually consist of equally spaced polysyllabic phrases (Fig. 11 B). The calling song durations vary from 15 s to 2 min, depending on the number of phrases. Syllable numbers change from 5 to 7 in a phrase (Fig. 11 C). The duration of syllables changes between 60–74 ms (Fig. 11 D). A syllable comprises two different parts. Part A contains a long pulse (lower amplitude) and Part B includes 3–5 short pulses (higher amplitude), where the last pulse of Part A is the loudest one (Fig. 11 D)
Published song data, used for comparison: Ragge & Reynolds 1998.