Eumodicogryllus bordigalensis (Latreille, 1804)

The calling song of males of E. bordigalensis from Novosedly consists of long, uninterrupted sequence of syllables which lasts several minutes. The normal duration of syllables were 0.122-0.149 s (r=0.132 s) and they are were consisted of 11-13 impulses (Fig. 5); among the normal syllables the shorter syllables were irregularly inserted (duration 0.023-0.088 s; 1-7 impulses) (Fig. 5). The intervals between the syllables were 0.120-0.530 s (r=0.300 s). The carrier frequency of the song shows a band between 4.6-15.5 KHz (Figs. 5 and 6). The song has low intensity (e.g. in comparison with Gryllus campestris LINNÉ, 1758) and it could not be usually heard from the distance longer than 10m. Crickets have night stridulating activity. First males started to sing at the late afternoon (at 7 p.m. 15.07.2005) and regularly stridulated from the sunset to the midnight which corresponds with field observation.

The oscillograms of the song of E. bordigalensis was previously published and commented by RAGGE and REYNOLDS (1998). The song of E. bordigalensis from France and Italy described by these authors slightly differs from our results. The authors found calling song consists of syllables repeated at the rate of about 2.5-4.0s and each composed of about 14-20 impulses. Each syllable lasted about 0.150-0.270s. The frequency of the carrier wave was 3.5-5 kHz. The differences can show to little local differences in song structure. For the comparison it is required to have material from more parts of the distributional area. The divergence of songs can be also caused by recording in lower temperature, when these authors used recordings in temperatures of 15°C and 22°C.

RAGGE and REYNOLDS (1998) also summarised older references to song of E. bordigalensis. More recently, the song was briefly described also by VAN ELST & SCHULTE (1995) and BENNET-CLARK and BAILEY (2002). VAN ELST and SCHULTE (1995) mentioned that the song is regular and consists of 2 syllables/s at 17 °C and 1 syllable/s at 12 °C. BENNET-CLARK and BAILEY (2002) described the song as short trills with dominant song frequency at 5 kHz. [1]

Referenties