Relatively large, compact cicada that appears singing at the end of June and begins to disappear in August, before other species such as the common cicada (Cicada orni), which in some places is still active acoustically in October.
Distribution- T. quadrisignata is relatively rare, having only been collected in Alto Alentejo (Castelo de Vide - Portalegre area) and Beira Alta (Serra da Malcata).
Ecology- In open woods and associated with chestnut trees (Castanea sativa), gum cistus (Cistus ladanifer), olive trees (Olea europaea), black oak (Quercus pyrenaica) and maritime pine (Pinus pinaster). In my field work, I found it mostly in chestnut trees and cistus, as in Alvarrões and near Portagem (Marvão), and more rarely in the other plants mentioned above. Besides this area (Serra de S. Mamede), which I have visited over the years, it was also mentioned for Serra da Malcata. I presume that this cicada may also occur in the north of the country, in areas further inland with chestnut woods and also in black oak.
It's a very shy cicada, which keeps quiet as soon as you feel someone approaching, and locating it and observing it in a close-up is a real challenge. The acoustic signal is very similar to that of another species of the same genus (Tibicina garricola), but as these two species occupy very distinct habitats, their distributions apparently do not overlap, i.e., they occur in allopathy (Quartau et al., 2001).
In studies of spectrum analysis (Quartau & Simões, 2003), T. quadrisignata uses a band with frequencies slightly lower than T. garricola (respectively 3 - 15 kHz, with maximum energy value of 8.34 kHz in quadrisignata and 5 - 13 kHz, with maximum energy value of 9.48 kHz in garricola), although the spectrum largely overlaps.
On the other hand, there are significant differences in the structure of the male genitalia, which suggest that two distinct patterns of specific divergence have occurred in cicadas: (i) cicadas, as in the genus Tettigettalna and others, where a very distinct acoustic divergence was achieved with very weak morphological differentiation, even in the genitalia; and (ii) cicadas, as in the case of Tibicina, where the opposite occurred, i.e., clear morphological differentiation with a merely subtle acoustic divergence.
Quartau, J.A., Simões, P.C., Rebelo, M.T. & André, G. (2001). On two species of the genus Tibicina Amyot, 1847 (Hemiptera, Cicadoidea) in Portugal, with one new record. Arquivos do Museu Bocage, Nova Série, vol. III (15): 401-412
Quartau, J.A. & Simões, P.C. 2003. Bioacoustic and morphological differentiation in two allopatric species of the genus Tibicina Amyot (Hemiptera, Cicadoidea) in Portugal.Deutsche Entomologische Zeitschrift, 50 (1): 113-119.