Tibicina steveni (Krynicki, 1837)

Hertach, Thomas & Nagel, Peter, 2013, Cicadas in Switzerland: ascientific overview of the historic and current knowledge of apopular taxon (Hemiptera: Cicadidae), Revue suisse de Zoologie 120 (2), pp. 229-269 : 245-247

Tibicina steveni (Krynicki, 1837)

German common name: Gelber Scherenschleifer

French common name: La Cigale de Steven ( Puissant, 2006)

The German name has been formed similarly to T.quadrisignata .It is the only species of the genus with yellow marks on the mesonotum, abroad yellow stripe at the posterior margin of the pronotum and with a yellow coloration of the basal wing venation in Central Europe.

DISTRIBUTION (Fig. 6)

Tibicina steveni was originally known as an eastern Mediterranean cicada. It was described from the Taurus Mountains ( Turkey) and is distributed in Azerbaijan, Armenia, Georgia, Ukraine (Crimea) (Sueur et al., 2003) and Bulgaria ( Gogala et al., 2005). The occurrence in Switzerland and in one place in France was unexpected

FIG.6

Distribution map of Tibicina steveni (top) including the data source for the records presented (below).

(Sueur et al., 2003). It has recently also been found in awider but fragmented range in the northern Apennine Mountains in Italy (pers. data).

Swiss populations of T.steveni have actually been known as “ Cicada san - guinea ”for more than 150 years (Bremi in Hagen, 1855). He estimated that the species was not rare in the Valais, although less abundant than C. orni ,but he had probably included observations of T.quadrisignata in his assessment. Judging by nine spe - cimens caught between 1891 and 1899 and preserved in different public collections

(NMBE, NMLS and NMS), the species must have occurred fairly frequently in the Martigny region (VS) at that time. Farquet’s(1940) “ C. haematodes ”at Mont Ravoire near Martigny must be T.steveni and is the only detailed chorological information published before Pillet (1993).

Tibicina steveni only occurs in the western parts of the Rhone Valley (VS) and afew of its side valleys ( Pillet, 1993). Some of the records made by Pillet are doubtful since T.quadrisignata has been reported from the same site subsequently (see previous section). For that reason the exact distribution area has to be reinvestigated for the western part of the Valais. Specimens from collections labelled with “Aïre” (GE, MHNG), “Peney” (GE, MHNG) and “Clarens” (VD, NMBE), all of them far away from the known distribution area, we suppose to be erroneous. The first two (Aïre and Peney) were reported by Maerky,who is known to have mixed up localities when labelling specimens. Moreover,the Peney label originates from Tournier,who was also an insect dealer (Hollier, pers. comm.). The third (Clarens) is without any further information, but there is also aspecimen of Tibicina quadrisignata preserved in the same collection and with the same handwriting from this site and it is probable that there have been labelling errors.

Sueur et al. (2003) hypothesized that the Swiss and French populations must be arelict of aformerly wider distribution of the species across Europe. Wesupport this opinion based on the following considerations: The hypothesis of arelictual occurrence in the western part of the distribution is verified by the recent observations in Italy,isolated populations are common for the Valais with its characteristic dry climate, and the biogeographical pattern with the main distribution area in the East (Europe and/or Asia minor) is not unique for species occurring in the Valais. Delarze (1987) has published alist of 21 beetles, two grasshoppers and one spider occurring in the Valais that are at least more abundant in Eastern Europe than in the Rhone Basin. He discussed the origins of the xerothermic flora and fauna and concluded that acolonisation of the Valais along the Jura Mountains and north of the Alps could not be excluded for some oriental insects since the late glacial period.

ECOLOGY AND THREAT

Tibicina steveni is astenoecious species preferring dry Scots Pine tree forests (= Ononido-Pinion,see Delarze &Gonseth, 2008) and oak woods (Quercion pubescenti-petraeae). The species inhabits closed habitats (Sueur et al., 2003). Singing males are often observed sitting on Scots Pine (Pinus sylvestris)or on Downy Oak ( Quercus pubescens ) ( Pillet, 1993). Sometimes they also sing in neighboured vineyards.

A good knowledge of the distribution and ecology of this attractive species is essential, because Switzerland is exclusively responsible for the conservation of the Central European populations. The population densities are low,the occurrence iso - lated and restricted to avery small area. Pillet (1993) already pointed out the severe threat especially due to the continuous expansion of the vineyards. Similar to T.quadrisignata ,this species is aperfect model for flagship species concepts in nature conservation.