Bioacoustics of Isophya speciosa

Diagnosis : I. speciosa differs from I. amplipennis by the slender male cerci with narrow apex and pointed apical/subapical tooth ( Figs 104 , 181 B); female lamella ( Fig. 129 ) is less laterally protruded; male stridulatory file ( Fig. 181 A) bears the largest number of teeth among the known representatives of the group—from 154–160 (in two males from NE Bulgaria , Byala, and SE Bulgaria , Kovach, respectively) to over 170 (Heller 1988) and has a length of 2.6–2.8 mm (present paper: two males from NE and SE Bulgaria , respectively) or possibly more. Male song ( Fig. 190 ) has four recognisable parts. The syllables are longer than these of the other studied species of the group (about 3.6 s at>27°С after Heller 1988 and 5.2 s at 24°С in a male studied here); possibly there are differences in the impulse interval and length of different parts of the song between I. speciosa and I. amplipennis but it is difficult to judge for this character due to the significant differences in the recording temperature of available recordings (compare Heller 1988: Abb. 33 for both species as well as this paper: Fig. 190 ).