Species Orosius ryukyuensis (Ishihara, 1965)

Orosius ryukyuensis (Ishihara), adult

© Copyright Murray Fletcher, Orange Agricultural Institute

Museums

Regional Maps

• Nesophrosyne ryukyuensis Ishihara, T. 1965. Two new cicadellid-species of agricultural importance (Insecta: Hemiptera). Japanese Journal of Applied Entomology and Zoology 9(1): 19–22 [19].

  Type data:

   Holotype EUMJ ♂ (coll: 9.vi.1964, A. Shinkai), Miyako Is., Ryukyus, Japan.

Generic Combinations

• Orosius ryukyuensis (Ishihara, 1965). —
  Linnavuori, R.E. 1975. Homoptera : Cicadellidae, Supplement. Insects of Micronesia 6(9): 611-632 [628]

Introduction

This species is closely related to O. lotophagorum and was first recorded in Australia by Behncken (1984), as O. lotophagorum ryukyuensis based on an identification by M.S.K. Ghauri. Behncken (1984) recorded it as a vector of little leaf and phyllody disease of bellvine (Ipomaea plebeia R.Br., Convolvulaceae). Shinkai (1964) reported it as a vector of sweet potato witch's broom in the Ryukyu Islands. The species may have been introduced to Australia from Japan.

Distribution

States

New South Wales, Northern Territory, Queensland

IBRA and IMCRA regions

IBRA

NSW, NT, Qld: Brigalow Belt South (BBS), Darwin Coastal (DAC), South Eastern Queensland (SEQ)

Ecological Descriptors

All stages: phloem feeder, vector (associated flora: Ipomaea plebeja F. Muell., 1886 [CONVOLVULACEAE] Bellvine; Ipomaea batatas (L.) Lam. [CONVOLVULACEAE] Sweet potato).

Diagnosis

♂♀. Length till tegminal apices about 3 mm, id. excluding tegmina about 2.8 mm. Head, pronotum and tegmina pale brownish, irregularly with black markings. Vertex with two black spots near cephalic margin and one black spot on each side near the eye which is often contiguous with a pair of mustache-shaped central black markings. Eyes fuscous. Ocelli reddish. Frons mostly black except base, with about seven stramineous bands on each side. Other black markings of head in front view generally as in N. orientalis (Matsumura, 1914). Pronotum a little darkened except the anterior part, with a pair of blackish spots near the anterior margin and irregular blackish vermiculate lines especially on both sides. Scutellum black anteriorly except both sides and central part which is often blackish near the antero-lateral margins and in some posterior area. Tegmina with black vermiculate lines well developed and remarkably infuscated at tegminal apices. Abdominal tergites black, with yellowish brown posterior margins, especially widely in the last two segments. Head medially as long as width between eyes, clearly longer than next the eye, with the anterior margin rounded. Pronotum as wide as head including eyes, less than 1.5 times the length of head. Tegmina sufficiently protruding the abdominal apex. Male plates each with about five spine-like setae uniseriate. Male genitalia similar to those of other congeneric species, though style has the caudal projection straightly prolonged and sharply pointed and aedeagus comparatively slender. Spinulation at apex of hind femur 1–2–2 (Ishihara 1965).

O. ryukyuensis is one of three species in which the aedeagal shafts are abruptly narrowed towards the apex. It can be differentiated from O. recurvus in ventral view by the aedeagal shafts being incurved throughout rather than abruptly incurved near the apex as in O. recurvus. From O. lotophagorum, it can be differentiated by the increasing width of the shafts in lateral view in O. lotophagorum while in O. ryukyuensis the shafts are more or less parallel sided from the base (Fletcher et al. 2016).

ID Keys

Fletcher et al. 2016: 5

Diagnosis References

Fletcher, M.J., Löcker, H., Mitchell, A. & Gopurenko, D. 2016. A revision of the genus Orosius Distant (Hemiptera: Cicadellidae) based on male genitalia and DNA barcoding. Austral Entomology [Date published Early version published online 1/9/2016: Paper version in 2017 on Vol. 56(2): 198–217] [12–13]

General References

Behncken, G.M. 1984. Orosius lotophagorum subsp. ryukyuensis (Hemiptera: Cicadellidae), a new vector of a little leaf disease in Australia. Australasian Plant Pathology 13(3): 35–36 [35–36]

Shinkai, A. 1964. Studies on Sweet Potato Witches' Broom Disease in the Ryukyu Islands. Govt Ryukyu Isl. Econ. Dept Agr. Sect. Spec. Res. Rpt 44 pp. [33]

History of changes