Oligoglena tibialis (Panzer, 1798)

Trilar, Tomi, Gjonov, Ilia & Gogala, Matija, 2020, Checklist and provisional atlas of singing cicadas (Hemiptera: Cicadidae) of Bulgaria, based on bioacoustics, Biodiversity Data Journal 8, pp. 54424-54424 : 54424

Oligoglena tibialis (Panzer, 1798)

Distribution

General distribution: Southern Europe: Albania, Bosnia, Bulgaria, Croatia, France, Greece, Italy, North Macedonia, Portugal, Romania, Slovenia, Serbia, Spain; Central Europe: Austria, Czech Republic, Hungary, Poland, Slovakia; Eastern Europe: Moldova, Russia (South European Russia), Ukraine; Middle East: Iran, Israel, Jordan, Lebanon, Turkey; Transcaucasia: Azerbaijan, Georgia, Russia (Chechnya); Central Asia: Kyrgyzstan, Uzbekistan; Northern Africa: Morocco, Tunisia (summarised by Duffels and van der Laan 1985 and Sanborn 2014).

There is a doubious citation of Oligoglena tibialis for Germany ( Kaltenbach et al. 1972, Nast 1972, Lodos and Kalkandelen 1981, Nast 1987, Quartau and Fonseca 1988), as it is not listed in the latest overview of fauna ( Nickel et al. 2016). There are also doubtful citations for Sicily ( Nast 1972, Quartau and Fonseca 1988) and Crete ( Nast 1972, Quartau and Fonseca 1988), as Oligoglena tibialis has never been found in recent field research with bioacoustic methods on these Islands (Thomas Hertach, personal communication, Trilar and Gogala 2010, Trilar and Gogala 2012a).

Distribution in Bulgaria: This small cicada is the most abundant and most widespread species of singing cicadas found in Bulgaria. The data for 125 localities are known (Fig. 56 ). In literature, we found the data in Nedyalkov (1908), Yoakimov (1909), Dlabola (1955), Bairyamova (1976) and Pelov (1968). Bairyamova (1992) lists the species for Rhodope Mts. for xerophylous and mesophylous oak-horn forests (Quercus-Carpinus) between 700 and 1000 m and beech forests (Fagus) between 1000 and 1400 m and Bairamova (1978) mentions the species for oak forests (Quercus). The species is also listed in overviews by Nast (1972), Nast (1987), Lodos and Kalkandelen (1981) and Quartau and Fonseca (1988), but without exact location data for Bulgaria.

In Bulgaria, it is distributed all over the country with known data in western Danubian Plane, eastern Danubian Plane, northern lowest hills of the Pre-Balkan, southern Lower Mountain Pre-Balkan, northern Balkan Mts., western Sub-Balkan valleys, Kraishte-Ichtiman, Vitosha Mt., True Sredna Gora Mt., Ograzhden-Vlachina Mts., Kyustendil-Blagoevgrad Middle Struma valley, Sandanski-Petrich Middle Struma valley, Pirin Mt., Dabrash-Batak western Rhodope Mts., Prespa-Chernatitsa western Rhodope Mts., Upper Thracian Plain, Tundzha-Burgas Valley, eastern Rhodope Mts., Haskovo Hills Land, Sakar Mt. and Strandzha Mt. (Fig. 56 ).

In this study, the majority of the population of Oligoglena tibialis was found between sea level and 800 m (91% of the population) (Fig. 57 ), but the rest is distributed between 801 and 1400 m. The highest find is registered at 1570 m a.s.l., where an unknown collector in Pamporovo collected one male and one female specimen, which are kept in the SOFM collection.

Notes

Acoustic behaviour: The song was described by Popov (1975), Joermann and Schneider (1987), Boulard (1995), Gogala et al. (1996) and Sueur and Puissant (2000).

The calling song contains two types of phrases (Fig. 58 ). The first phrase (duration 920 ± 89 ms) is a sequence of short echemes (SE) (duration 48 ± 8 ms) followed by a long echeme (LE) (duration 292 ± 50 ms). Usually groups of short first phrases with 2-5 SE are separated by longer first phrases with a higher number of SE (11-13), but there is little regularity in this pattern. The second phrase consists of regularly repeated SE (duration 54 ± 11 ms, 38-76 SE) ( Gogala et al. 1996, Joermann and Schneider 1987). The first phrase could last for minutes, then the animal suddenly switches to a second phrase, which could last only a few or ten seconds, then the first phrase appears again. It has often been observed that, after the second phrase, the males stopped singing and flew away. The spectrum of the calling song contains two frequency bands: a main band between 12 and 22 kHz with a maximum between 14 and 18 kHz and sometimes with a secondary peak near 12 kHz and a second band with a maximum between 7 and 8 kHz ( Gogala et al. 1996).

Selected sound samples of Oligoglena tibialis are available on the web pages Songs of the European singing cicadas ( Gogala 2020).

Materials: Suppl. material 13

Diagnosis

Oligoglena tibialis (Fig. 55 ) is one of the smallest singing cicadas in Europe, usually found on bushes and small trees. In areas where the shrubs were predominantly occupied by another species, i.e. Tettigettula pygmea , which has a song of a similar spectrum, Oligoglena tibialis is regularly found singing in meadows, alfalfa fields and on other green plants. The males sing all day long when the weather is fine and the ambient temperature is not too low (above 20°C). The males chirp their calling song from one place, a small branch or leaf, for one or more minutes, then fly away, find another position and start singing again ( Gogala et al. 1996).

Figures

Figure 55. Oligoglena tibialis male.

Figure 56. Map with localities of Oligoglena tibialis in Bulgaria. Black - literature data, blue - data from collections, red - bioacoustic data collected in this survey.

Figure 57. Altitudinal distribution of Oligoglena tibialis. The percentage of the recorded localities is displayed in 200 - metre altitude zones.

Figure 58. Calling song of Oligoglena tibialis. (A) spectrogram and oscillogram of the calling song, showing the transition from the first phrase to the second; (B) oscillogram of the enlarged part of the transition from the first phrase to the second one corresponding to the inverted window in (A).