Euscelis ohausi Wagner, 1939

Koufakis, Ioannis E., Pappas, Maria L., Kalaitzaki, Argyro P., Tsagkarakis, Antonios E., Thanou, Zoi N., Tzobanoglou, Despina K. & Broufas, George D., 2022, First record of two leafhoppers, Euscelis ohausi and Euscelidius variegatus, for the island of Crete, Greece (Hemiptera: Cicadellidae), Fragmenta entomologica 54 (1), pp. 185-192 : 188-189

Euscelis ohausi Wagner, 1939

Material examined. GREECE: (CRETE), CHANIA, Zymvragou , 35°26’27.1”N 23°45’25.0”E, 300 m, 15 November 2017 (0 ♂, 1♀) , 23 May 2018 (5♂, 3♀) , 29 October 2018 (0 ♂, 1♀); Nerokourou , 35°29’12.8”N 24°01’28.0”E, 10m, 09 May 2018 (2♂, 0 ♀), 03 September 2018 (2♂, 1♀) , 17 September 2018 (1♂, 3♀) ; Pyrgos , 35°29’31.7”N 23°38’42.0”E, 30 m, 23 May 2018 (3♂, 2♀) ; Lousakies , 35°28’34.3”N 23°38’02.7”E, 150 m, 03 September 2018 (2♂, 2♀) ; Zounaki , 35°28’55.3”N 23°49’45.8”E, 180 m, 24 May 2019 (0 ♂, 1♀) ; Souda , 35°29’38.9”N 24°02’49.8”E, 7 m, 9 May 2019 (1♂, 0 ♀), 27 November 2019 (1♂, 1♀) . RETHYMNO, Episkopi , 35°20’17.0”N 24°20’12.0”E, 66 m, 12 April 2019 (1♂, 0 ♀) . HERAKLION, Fodele , 35°22’44.5”N 24°57’37.2”E, 45 m, 01 July 2019 (1♂, 1♀) ; Agia Varvara , 35°09’15.9”N 25°00’43.6”E, 519 m, 21May 2020 (1♂, 0 ♀) .

Diagnosis. The genus Euscelis Brulle , belonging to the subfamily Deltocephalinae and tribe Athysanini , comprises more than 50 species (and subspecies) with most of them from the Palearctic Region (McKamey 2001; Hoebeke & Wheeler 2010). Specimens of E. ohausi collected from Crete were identified morphologically using identification keys and scientific publications ( Thanou et al. 2018; Biedermann & Niedringhaus 2009 & Le Quesne 1969).

Euscelis ohausi can be readily distinguished either from E. obsoleta (Kirschbaum, 1858) or from other similar-appearing Nearctic leafhoppers of the genera Euscelidius and Streptanus , by the distinct male aedeagus ( Hoebeke & Wheeler 2010).

The base colour of adults is yellowish brown and the overall body length ranges from 3.4 to 4.7 mm in males, while in females from 4.1 to 5.5 mm. Regarding males, the aedeagus ( Fig. 1 ) is broad with stout recurrent appendages from apex to below level of gonopore ( Le Quesne 1969; Biedermann & Niedringhaus 2009). The vertex has a light brownish colour with two curved blackish streaks near anterior margin and several blackish spots, including two large ones posteriorly. The pronotum has a light brownish colour with some dark spots, sometimes forming longitudinal streaks. The forewings are generally longer than the abdomen in male, and slightly shorter in female. The face ( Fig. 3 ) has a light brownish colour with variable dark markings with dark transverse stripes on frontoclypeus, sometimes fused into longitudinal median patch. Sometimes, there is a dark patch on anteclypeus and dark areas around base of antenna. Scutellum ( Fig. 4) has a light brownish colour, often with dark markings. Furthermore, there are highly variable dark mottling of forewings, typically evenly distributed on wing ( Le Quesne 1969; Ossiannilsson 1983; Hoebeke & Wheeler 2010).

Distribution. Euscelis ohausi is a Palearctic leafhopper widely distributed in Western Europe; it has been recorded in Belgium, Britain I., Danish mainland, French mainland, Germany, Poland, Portuguese mainland, Switzerland, The Netherlands ( de Jong et al. 2014) and Luxemburg ( Niedringhaus et al. 2010). In Greece, E. ohausi has been recorded by Thanou et al. (2018) with the use of Malaise traps and sweep net in several regions such as Mantoudi (Euboea), Ancient Corinth (Corinth), Elaea (Kiparissia, Messinia), Athens (Attica), Pelekanada (Messinia) and in different habitats such as olive groves, citrus orchards, vineyards, alfalfa, green pepper and fresh tomato. Recently, it was reported as new species to North America, in the United States of America (Oregon and Washington) and in Canada (British Columbia) ( Hoebeke & Wheeler 2010). Despite of being found in several areas of the Greek mainland, its presence in the Greek islands is still unknown. This study confirms the presence of E. ohausi in several areas of Crete in a wide range of altitudinal spectrum from 10 m up to 519 m. Individuals E. ohausi were sampled in relatively high numbers from the herbaceous cover of olive groves in Crete.

Bio-ecology. It is found mostly in sunny, humid to moderately dry sites ( Nickel 2003). Studies performed in Germany classified E. ohausi in vulnerable conservation status and show it overwinters at the egg stage, having one generation per year, as an oligophagous insect restricted to one plant family ( Fabaceae ), specifically to Cytisus scoparius and Genista anglica ( Remane et al. 1998; Nickel & Remane 2002). Moreover, there are two forms of E. ohausi in central Europe with different host plant range, coloration, body size and distribution. The form “typica” lives on Genista anglica near the coast of the North Sea and the Baltic Sea in Germany, while the form “singeri” feeds on Cytisus scoparius in central and southern Germany and Luxemburg ( Nickel 2003; Niedringhaus et al. 2010). Since both forms can interbreed and produce fertile offspring some authors consider them as synonyms at species level while others as distinct subspecies ( Nickel 2003). According to the literature, as regards their occurrence to different host plants, the two forms are associated with Genista anglica and Cytisus scoparius . In our study, E. ohausi adults were observed on Gramineae plants (several grasses), particularly wild oats ( Avena sativa ) from May to October. The two previously recognized host plants, G. anglica and C. scoparius , were not present in the study area.

Figures

Fig. 1 – Male genitalia of Euscelis ohausi.

Fig. 3 – Dorsal view of male and female Euscelis ohausi.