Populicerus ambigenus ( Dubovskiy, 1966 )

Tishechkin, Dmitri Yu., 2018, Contributions to the study of Idiocerinae (Homoptera: Auchenorrhyncha: Cicadellidae) of Central Asia with notes on synonymy, Zootaxa 4446 (4), pp. 541-554 : 543-545

Populicerus ambigenus ( Dubovskiy, 1966)

Figs. 3–5 , 14–41

Idiocerus ambigenus DubOvskiy, 1966: 118

Idiocerus tenellus DubOvskiy, 1966: 118 –119. Syn. n.

Material examined. 1. Kyrgyzstan, northern slopes of Turkestan Mtn. Range, the Layli-Mazar River Valley 2–3 km upstream from the source of the Laylyak River, 23. VI. 2016, 6 ♂ (locality No. 11 on Fig. 2 ).

2. Kyrgyzstan, Alay Mtn. Range, ca. 25 km SE of Kyzyl-Kiya, Abshirsay Gorge, from Salix sect. Helix . 14– 15. VII. 2014, 14 ♂, 6 ♀ (locality No. 12 on Fig. 2 ).

3. Kyrgyzstan, Alay Mtn. Range, the Kurshab River Valley ca. 10 km NW of Gul’cha Town, from Salix alba . 5. VII. 2014, 8 ♂, 2 ♀, signals of 1 ♂ recorded on disk at 24 o C (locality No. 13 on Fig. 2 ).

4. Kyrgyzstan, Central Tien Shan, the Dzhumgal River Valley E of Chaek, from Salix sect. Helix . 2. VII. 2013, 2 ♂, 1 ♀; 30. VI. 2014, 6 ♂, 3 ♀, signals of 3 ♂ recorded on disk at 26o C (locality No. 14 on Fig. 2 ).

5. Kyrgyzstan, the Chu River near the western extremity of the Issyk-Kul Lake (ca. 6 km W of Balykchi Town), from Salix sect. Helix . 6. VII. 2013, 2 ♂ (locality No. 15 on Fig. 2 ).

Taxonomic notes and description. I. ambigenus was described based on a series of 20 males and 100 females from Ferghana and Alay Mtn. Ranges collected on willows ( Dubovskiy, 1966). I. tenellus was described in the same monograph based on one male from the foothills of Chatkal Mtn. Range collected on desert poplar ( Populus sp. from the subgenus Turanga ). Later both species were transferred to the genus Populicerus Dlabola, 1974 by Mityaev (2002). He treats these forms as separate species, but points out that both species feed on willows ( Mityaev, 1971, 2002).

According to the original descriptions and the key to species ( Dubovskiy, 1966), in external appearance males of P. ambigenus differ from P. tenellus by orange or orange yellow coloration (greenish yellow in males of P. tenellus ). In fact, both orange yellow and greenish males can be found in the same sample collected from the same host ( Figs. 3–4 ). Females are always paler than males, yellowish green ( Fig. 5 ).

According to Dubovskiy (1966), P. ambigenus has a wider penis stem with subapical processes slightly bent backwards in side view (Figs. 14–15), while in P. tenellus the penis is more narrow, with a subapical processes parallel to the stem (Figs. 17–18). In fact, penis shape varies between undoubtedly conspecific males whose calling signals were investigated (Figs. 24–25 and 26–27) as well as between males from the same sample (Figs. 28–32).

The main diagnostic trait in male genitalia of P. ambigenus , according to Dubovskiy (1966), is an additional large thick seta situated on the style proximal to two subapical close-set ones and separated from them by one small hair-like seta (Fig. 16); in P. tenellus the additional thick seta is absent and the style bears only a row of small hairlike setae (Fig. 19; Dubovskiy, 1966; Mityaev, 1971). Actually, the shape and location of setae on the style can vary not only among specimens from the same locality and host, but even on left and right style of the same male (Figs. 20–23). Sometimes on one style, the additional seta is situated immediately after two subapical ones (Fig. 20). Occasionally, the length of these setae on left and right styles differs by almost 1.5 times (Fig. 21). In particular, the length of these setae is somewhat different in two undoubtedly conspecific males (Figs. 22–23).

Thus, neither of the traits used previously for discrimination between these two forms is species-specific. For this reason we regard P. ambigenus and P. tenellus as conspecific. Additional evidence of the synonymy is that both forms dwell on willows ( Mityaev, 1971, 2002 and our data). The finding of a single male on desert poplar apparently is accidental, since this tree always grows in river valleys together with willows. Both taxa were described in the same monograph on the same pages; as first reviser we choose P. ambigenus as the valid name.

Male abdominal apodemes of this species were never described; they are shown in Figs. 33–35.

Body length (including tegmina): ♂, 5.4–6.1 mm; ♀, 6.7–7.2 mm.

Calling signals. Calling signal consists of short syllables lasting ca. from 0.5 up to 3– 3.5 s each ( Figs. 36–37 ). The main part of a syllable is a succession of partially merged pulses; pulses at the beginning of a syllable as a rule are indistinct ( Figs. 38–41 ). Some syllables end with a short succession of 3–6 abrupt short discrete pulses of another shape that sound like clicks for human ear (two last syllables of Fig. 37 ). Sometimes the male produces a succession of syllables, in which the end syllables are longer and have higher amplitude and more elaborate pattern than the initial ones; such signal can be classified as a phrase ( Fig. 37 ).

Distribution. Kyrgyzstan, Uzbekistan, almost all the territory of Kazakhstan, evidently, also Tajikistan. On different willow species in foothills and low mountains; in steppe and desert zones mainly in the floodplains. Common and often numerous species.

Figures

FIGURES 3–13. IdiOcerinae, dOrsal vieW (3–8 and 10–13) and face (9). 3–5―Populicerus ambigenus (3–4―male, 5―female); 6–8―Sahlbergotettix salicicola (6―male, 7–8―female); 10–13―Idiocerus bilituratus (9–11―male, 12– 13―female).

FIGURES 1–2. Maps Of lOcalities in Russia and Kazakhstan (1) and in Kyrgyzstan (2), Where the materials Were cOllected. 1―Russia, Dosang Railway Station 60 km North of Astrakhan; 2―Kazakhstan, southern part of the Syrdarya Karatau Mtn. Range, the mouth of Sayasay Gorge; 3―Kazakhstan, western bank of the Ili River ca. 45 km downstream from Bakanas, environs of Akzhar Village; 4―Kazakhstan, ca. 45 km NE of Sarkand Village, the Lepsy River at the exit from the gorge to the plain; 5―Kyrgyzstan, foothills of Chatkal Mtn. Range, environs of Ala-Buka Village; 6―Kyrgyzstan, Chatkal Mtn. Range, Sary-Chelek Biosphere Nature Reserve, environs of Arkyt Village; 7―Kyrgyzstan, foothills of Chatkal Mtn. Range, environs of Ak-Jol village 25 km N of Tash-Kumyr; 8―Kyrgyzstan, foothills of Ferghana Mtn. Range, the Aksu River Gorge on the left bank of the Lower Naryn River opposite to Tash-Kumyr Town; 9―Kyrgyzstan, basin of the Lower Naryn River, the Kara-Suu River 15–20 km upstream from Kara-Kul Town; 10―Kyrgyzstan, foothills of Ferghana Mtn. Range, the Kara-Unkur River Valley in the environs of Kyrghyz-Gava Village; 11―Kyrgyzstan, northern slopes of Turkestan Mtn. Range, the Layli-Mazar River Valley 2–3 km upstream from the source of the Laylyak River; 12―Kyrgyzstan, Alay Mtn. Range, ca. 25 km SE of Kyzyl-Kiya, Abshirsay Gorge; 13―Kyrgyzstan, Alay Mtn. Range, the Kurshab River Valley ca. 10 km NW of Gul’cha Town; 14―Kyrgyzstan, Central Tien Shan, the Dzhumgal River Valley E of Chaek; 15―Kyrgyzstan, the Chu River near the western extremity Of the Issyk-Kul Lake (ca. 6 km w Of Balykchi TOWn).

FIGURES 36–47. OscillOgrams Of male calling signals Of IdiOcerinae. 36–41―Populicerus ambigenus; 42– 43―Sahlbergotettix salicicola; 44–47―Idiocerus bilituratus. Faster OscillOgrams Of the parts Of signals indicated as “38–41”, “43”, and “46–47” are given under the same numbers.