Orseolia graminicola (Kieffer & Docters van Leeuwen-Reijnvaan)

Kolesik, Peter & Gagné, Raymond J., 2020, A review of the gall midges (Diptera: Cecidomyiidae) of Indonesia: taxonomy, biology and adult key to genera, Zootaxa 4847 (1), pp. 1-82 : 50-51

Orseolia graminicola (Kieffer & Docters van Leeuwen-Reijnvaan)

[ Figs 28 a–e]

Clinodiplosis graminicola Kieffer & DvLR, 1910: 127 .

Pachydiplosis graminicola (Kieffer & DvLR): Kieffer (1913: 224) , new combination.

Orseolia graminicola (Kieffer & DvLR): Gagné (1973: 507) , new combination; Gagné (1985: 139), revision.

Type series. Syntypes, male(s) and female(s), reared from Cynodon dactylon (L.) Pers. ( Poaceae ) in Salatiga, Java, iv-1909. The types are likely lost ( Gagné & Jaschhof 2017).

Description. The relevant character states and figures are from Kieffer & DvLR (1910).

Adult. Length 2.5 mm in male, 3.5 mm in female.

Male. Flagellomeres [ Fig. 28c ] and terminalia [ Fig. 29e ], generally as for genus.

Female. Flagellomere [ Fig. 28d ] as for genus.

Pupa, larva unknown.

Remarks. This species appears similar to O. oryzae . It differs from O. difficilis Gagné , which causes similar galls on the same host plant in India, in the more strongly tapered gonostylus and the narrower hypoproct ( Gagné 1985 ).

Biology. This species causes a leaf sheath gall on Cynodon dactylon (Poaceae) described by DvLR &DvL (1926, gall No 52, Figs 29 , 30 ) [ Figs 28b, d ]. Females deposit eggs on the upper surface of the leaves at night. Newly hatched larvae penetrate the young leaves until they have reached the upper end of the growth tip where they live for some time. A number of axillary buds develop which grow into small stems. Leaf sheaths become enlarged and forced outward by the great number of buds, until a fusiform gall is produced, which is often somewhat laterally compressed [ Fig. 28b ]. A leaf then develops from the primary axillary buds like a cylindrical case that encloses the larva, in this way forming a gall chamber. The leaf sheaths open at the top and the young twigs and galls emerge [ Fig. 28d ]. An aperture is formed near the top of the gall from which the adult gall midge emerges. After some time, when the larvae have pupated, all the axillary buds, both those in which a larva lives and the uninfected ones, begin to grow.

Geographical distribution. This species is currently known from Java: Salatiga , alt. 600 m, iv-1909 ; Semarang , i-1910 ; Candi, near Semarang , alt. 100 m, viii-1912 ; Roban, near Pekalongan , vi-1913 .

Figures

FIGURES 28a–e. Orseolia graminicola: a, male flagellomere; b, young gall on Cynodon dactylon; c, female flagellomere; d, mature gall on Cynodon dactylon; e, male terminalia (ventral). Figs a, c, e from Kieffer & DvLR 1910), Figs b and d from DvLR & DvL (1926, Figs 29, 30). Arrows indicate galls.

FIGURES 29a–g. Orseolia javanica: a, gall on Imperata cylindrica (arrow indicates one of two galls; Fig. II-5 of DvLR & DvL (1926)); b, male terminalia; c, 12th male flagellomere; d, 3rd female flagellomere; e, 12th female flagellomere; f, 3rd female flagellomere; g, male terminalia (dorsal). Figs b–e from Kieffer & DvLR (1910) depicting types (now lost), Figs. f, g from Gagné (1985) of specimens in BMNH.

FIGURES 30a–o. Orseolia orientalis: a–b, galls on Oplismenus compositus (Figs 32, 33 of DvLR & DvL (1926)): a, young gall (ga = gall); b, mature gall (gb = gall breaking point); c, wing apex; d, tarsal claw and empodium; e, palpus; f–i, male: f, terminalia (dorsal); g, 3rd flagellomere; h, 6th flagellomere; i, 12th flagellomere; j-k, female: j, 3rd flagellomere; k, 10th tergum and cerci (dorsolateral: arrow indicates pair of thick setae on cercus); l–o, pupa: l, dorsal spines on 3rd abdominal tergum; m, prothoracic spiracle (lateral); n, prothoracic spiracle (ventral); o, anterior segments (lateral). Figs j–l from Gagné (1985).