Bioacoustics of Isophya plevnensis

Isophya pravdini pravdini Peshev , syn.n. : Peshev 1985 (sp.&ssp.n.). Morphological description : Peshev 1985 (both as I. plevnensis and I. pravdini pravdini ). Karyotype : Warchałowska-Śliwa et al. 2008 (as I. pravdini pravdini ). Synonymy : Peshev (1985) described I. plevnensis and I. pravdini pravdini in the same publication comparing them only with I. modesta and not to each other. The small differences noted and the new data gathered from morphology and song were not sufficient to recognise these two taxa. Therefore we regard them as subjective synonyms and accept the name Isophya plevnensis as valid due to its first mentioning in the latter publication. Furthermore, I. pravdini was described as a polytypic species with three subspecies, each belonging to a different species (Chobanov 2009a; see below) and thus placing I. pravdini in synonymy maintains the stability and universality of nomenclature as per the requirements of the ICZN (1999). Supplement to the description and a diagnosis : Body colouration dark green or blueish-green. Colouration of the lateral parts of tergites has a tendency to opalescence. The disc of tegmina in both sexes is dark, brownishgreen. Male tegmina have brown stridulatory area. CuP is light, yellowish, longer and thicker than that in I. miksici and I. clara , about 2/3–3/4 of the width of metazone. Male tegmina are slightly uplifted due to the vertical costal area but their discs are not distinctly bulged. The stridulatory file ( Figs 152 A) has a length of 3.2–3.7 mm—longer than that of I. miksici and about equal to that of I. andreevae , but has a larger number of teeth (100–130). The female stridulatory apparatus is shown in Fig. 152 C. The apex of male cerci bears a wide pointed tooth ( Fig. 152 B), which is longer than that of I. miksici (and the Belgrade populations of I. clara ) and wider than that of I. andreevae and the typical I. clara . The song ( Fig. 157 ) is hardly recognisable from that of I. andreevae though the syllables’ shape (amplitude modulation) slightly differs (cf. Figs 148, 149 with 157). From the song of I. miksici (and partly I. clara ) it differs in longer syllables, longer syllable interval, smaller groups of syllables, bigger number of impulses within the syllable, and very rare occurrence of after-clicks. Bioacoustics : The song was investigated in specimens from two localities near Apriltsi (Stara Planina Mountain foothills) at 25–27°С and consists of single or groups of two syllables (rarely up to 4). The interval between the syllables was usually 2–4 s up to more than 7 s. The syllables had 26–44 impulses (mean 39±3; n=43) and lasted 222–390 ms (mean 283±48; median 260; n=43). Of the available records only two syllables had a single after-click and thus the syllables had a total length of 530–540 ms. The intervals between impulses, similarly to these in I. andreevae and I. miksici , are longer at the beginning of the syllable and shorter at its end (sometimes increasing between the last 2–3 impulses) having length of (3)5–15 ms (mean 7.4 ms), up to 20 and even 32 ms between first impulses. The number of impulses and the syllables length varied between individuals and, contrary to the expectations, at 27°С the values were higher than at 25°С, which obviously reflects individual peculiarities. This supports our decision not to regard the difference of 1°С between the air temperatures during the recordings of I. miksici and I. plevnensis (27 and 28 °С) as resulting in bigger differences between the songs of these taxa. Though the great similarities, the significant differences between song parameters and number of stridulatory teeth (as well as some morphologic differences) support the distinction between the latter taxa.