Dryadomorpha Kirkaldy, 1906

Sanna, Francesco & Poggi, Francesco, 2022, First record of three alien Auchenorrhyncha species from Europe: Acanalonia bivittata (Say, 1825), Branchana xanthota Li, 2011, and Dryadomorpha pallida Kirkaldy 1906 (Hemiptera: Auchenorrhyncha: Acanaloniidae, Cicadellidae), Zootaxa 5194 (2), pp. 273-282 : 278-280

Genus Dryadomorpha Kirkaldy, 1906

Systematics and distribution. The leafhopper genus Dryadomorpha Kirkaldy, 1906 belongs to the tribe Drabescini , subtribe Paraboloponina in the subfamily Deltocephalinae , with Dryadomorpha pallida Kirkaldy 1906 as type species. Up to now, 9 species have been described, occurring in the Afrotropical, Palearctic, Oriental and Australian regions ( Zahniser & Dietrich, 2013; Zahniser, 2007 onward).

Dryadomorpha pallida is recorded from Australia, Bangladesh, Cape Verde, China, India, Israel, Japan, Java, Laos, Nepal, Philippines, Seychelles, Singapore, Sri Lanka, Taiwan, Thailand ( Webb, 1981), Afghanistan, Iran ( Nast, 1972), Pakistan ( Khatri & Rustamani, 2011), Korea ( Kim & Jung, 2022), and United Arab Emirates ( Gnezdilov, 2022). Starting from autumn 2018, D. pallida has been collected by both authors in northern Italy (Veneto and Lombardia regions).

Material examined. 1 ♀, Italy, Veneto, prov. Verona, Bovolone , 23 m, 45.276240, 11.141983, light trap, 10.X.2018, F.Sanna leg. ( CS) .

2 ♂♂, 1 ♀, Italy, Veneto, prov. Verona, Bovolone , 23 m, 45.276240, 11.141983, hand-picked, 3.VII.2019, F.Sanna leg. ( CS) .

1 ♂, 1 ♀, 12 nymphs, Italy, Veneto, prov. Verona, Bovolone , 23 m, 45.276240, 11.141983, hand-picked, 26.VIII.2019, F.Sanna leg. ( CS) .

3 nymphs, Italy, Veneto, prov. Verona, Bovolone , 23 m, 45.276240, 11.141983, hand-picked, 28.VIII.2019, F.Sanna leg. ( CP) .

4 ♂♂, 1 ♀, 1 nymph, Italy, Veneto, prov. Vicenza, Asigliano Veneto, 19 m, 45.314653, 11.449743, hand-picked, 25.VIII.2020, F.Sanna leg. ( CS) .

2 ♂♂, 2 ♀♀, Italy, Veneto, prov. Vicenza, Asigliano Veneto, 19 m, 45.314653, 11.449743, hand-picked, 13.VIII.2021, F.Sanna leg. ( CS) .

1 ♂, 3 ♀♀, Italy, Veneto, prov. Verona, Bovolone , 23 m, 45.276240, 11.141983, light trap, 28.VIII.2021, F.Sanna leg. ( CS) .

1 ♂, 1 ♀, Italy, Veneto, prov. Verona, Bovolone , 23 m, 45.276240, 11.141983, light trap, 7.IX.2021, F.Sanna leg. ( CS) .

2 ♂♂, 1 ♀, Italy, Lombardia, prov. Lecco, Maresso , 291 m, 45.689722, 9.355833, light trap, 5.VII.2021, F.Poggi leg. ( CP) .

Morphology. Adult ( Figs 3A–B ): body length of the specimens collected in Italy 5.2–5.65 mm in males and 6.4–6.8 mm in females; body yellowish green; head wider than the pronotum with a long, acute-angular vertex, antennae passing half the body length; forewings translucent, yellowish gray, presenting brown apical cells, two dark spots at the union between the commissural borders and the anal veins and a third, bigger spot at the end of the cubital cell. Veins often slightly orange in males.

Male genitalia; ventroposterior margin of pygofer with a darkly pigmented area ( Fig. 3F ); subgenital plates elongate, triangular ( Fig. 3E ); style moderately long with basal apophyses prominent and apical process moderately long, curved ventrally ( Fig. 3G ); aedeagus with a thin, slender shaft and two apical processes slightly curved, strongly divergent and directed dorsally ( Figs 3H–I ).

A more detailed description is provided by Webb (1981).

5 th instar nymph ( Figs 3C–D ); body length 4–6 mm, slender, yellowish green with a thin, teal longitudinal stripe and two wider teal stripes on the sides; vertex very sharp (median length 1.7–2 times the width between the eyes) with concave sides, anterior margin acutely angled, apex brown and narrowly rounded; vertex-face transition sharp, carinate at the apex; face very elongated with a prominent, median keel near the apex ( Fig. 3C ); anteclypeus and postclypeus from green to brown; keel with two transversal dark brown stripes; antennae as long as the body, reaching the end of the abdomen; wing pads yellow, legs greenish yellow; abdomen with two lateral rows of setae, tergites VII and VIII with additional setae on hind corners; pygofer with a pair of long apical cylindrical appendages, widely separated at base and covered with long setae.

Biology and host plants. According to observations made by the first author in Bovolone (VR) up to August 2022, the species seems to be able to complete 2–3 successive generations per year, with adults mainly present from early July to late September/early October, and juvenile stages present in June and from late July to the end of September. No adults were observed before the end of June. Both young and adults mainly live on lower leaf surface, where they cause superficial browning due to their trophic activity. So far, in northern Italy, adults and nymphs (1st to 5th instar) have mostly been obtained from the ornamental tree Lagerstroemia indica L. (in Italy cultivated or casual alien species), as well as reported for adults in Korea ( Kim & Jung, 2022). The specimens were found only on unpruned trees, while no specimens were found on ornamental trees periodically pruned by removing 1–2 years old branches during winter. The evidence suggests that the species probably overwinters as eggs that are laid under the bark of the young branches. D. pallida has been reported also from Ziziphus jujuba Mill. ( Zhang & Webb, 1996), present in Italy both as cultivated and as naturalized alien species, and Lumnitzera racemosa Willd. ( Evans, 1966) , absent in Italy.

Remarks. The general appearance of the 5th instar nymph, matches the description provided by Dmitriev (2004) for the genus Dryadomorpha , based on Dryadomorpha metrosideri (Osborn, 1934) nymph. Differently from D. metrosideri , D. pallida presents an apical process on head and a longitudinal carina on face, characters that allows to clearly distinguish the two species. These morphological differences between the nymphs suggest that D. pallida and D. metrosideri are distinct taxa, unlike the possibility considered by Gnezdilov (2022) that they could be a single species. It is also noteworthy that the head of Dryadomorpha nymphs, according to the species, can have a longitudinal carina, as well as others Drabescini nymphs and differently from what Dmitriev (2004) reported.

Figures

FIGURE 3. Dryadomorpha pallida (specimens from Italy, Veneto). A. male, dorsal habitus; B. female, dorsal habitus; C. head of 5th instar nymph, lateral view; D. 5th instar nymph, dorsal habitus; E. subgenital plates and valve, dorsal view; F. left pygofer lobe, lateral view; G. left style, ventral view; H. aedeagus and connective, ventral view; I. aedeagus and connective, lateral view.