Procystiphora phyllostachys Jiao & Bu

Jiao, Kelong & Bu, Wenjun, 2010, Notes on the genus Procystiphora Felt, 1915 (Diptera: Cecidomyiidae) with description of one new species inducing galls in branchlets of a bamboo in China, Zootaxa 2717, pp. 53-61 : 54-59

Procystiphora phyllostachys Jiao & Bu , sp. nov.

Adult. Body colour orange. Body length: 2.8–3.0 mm in male (n=8); 3.8–4.0 mm (ovipositor retracted) and 5.6– 5.9 mm (ovipositor completely exserted) (n=8). Wing length (measured from arculus): 2.3–2.4 mm in male (n=8); 2.7–2.8 mm in female (n=8). Wing width: 0.93–0.95 mm in male (n=8); 1.0– 1.1 mm in female (n=8).

Head ( Fig. 21 ): Eye bridge 5 facets long in the middle of vertex as in Fig. 21 . Palpus as in Figs. 1 and 9 . Male antenna ( Fig. 22 ) with 18 flagellomeres; female antenna ( Fig. 23 ) with 18–20 flagellomeres; pedicel subglobular, smaller than scape, both densely covered with setae and scales ventrally; node of all flagellomeres subcylindrical, a little broadened subbasally, male neck relatively long, variously 0.2–0.7 times length of node, female neck of all flagellomeres rather shorter, hardly apparent; each node with 2 (rarely 3 in female) horizontal, appressed, bandshaped circumfila, subapically and subbasally respectively linked by two similar longitudinal circumfila, and 2 whorls of extraordinarily prolonged, strong and irregular setae, one basal and one subapical; flagellomeres from 1st to the penultimate progressively shorter, first and second flagellomeres fused; male 3rd flagellomere as in Fig. 4 ; male terminal flagellomere rounded apically, as in Fig. 2 ; female 3rd flagellomere as in Fig. 10 ; female terminal flagellomere prolonged, and rounded apically, as in Fig. 11 .

Thorax: Wing ( Fig. 3 ) hyaline, sparsely covered with narrow scales and setose, 2.50–2.53 times as long as wide in male and 2.60–2.70 times in female. Vein Sc weak, C, R1 and R5 strong; R1 joining C before middle wing, R5 arched slightly, joining C slightly anterior to wing apex; vein M3 rather weak; vein Cu forked at a approximately 70 degree angle, vein PCu parallel with Cu. Legs densely covered with narrow scales and sparse setae; femur of fore-, mid- and hindlegs shorter than tibia, with proportions respectively 0.82–0.88, 0.90–0.94 and 0.89–0.93 in male, and 0.84–0.88, 0.82–0.86 and 0.90–0.93 in female; the second tarsus of fore-, mid- and hindlegs shorter than tibia, with proportions respectively 0.86–0.92, 0.90–0.95 and 0.90–0.97 in male, and 0.45–0.50, 0.51–0.56 and 0.74– 0.79 in female. Tarsal claw ( Fig. 5 ) toothed on all legs; empodium as long as tarsal claw; pulvillus cylindrical, 1/2 length of claw.

Male abdomen: Each tergite covered with scales uniformly; first through sixth tergites with posterior margins wider than anterior, with an irregular but mostly single, posterior row of setae interrupted in the middle, and with anterior pair of trichoid sensilla; first through fourth tergites without lateral setae, fifth through sixth tergites with respectively 0–3 and 5–9 pairs of lateral setae; seventh tergite convex at anterior margin and concave at posterior margin, with two small arcuate depressions along middle of posterior margin, covered with anterior pair of trichoid sensilla, many scattered lateral and posterior setae; eighth tergite much narrower than seventh, evident as 2 separate, short and rhomboid sclerites, with anterior pair of trichoid sensilla and 1–2 pairs of posterior setae; second through eighth sternites densely covered uniformly with scales, with an irregular but mostly single, posterior row of setae, and covered with many scattered lateral and central setae; second through sixth sternites sub-rectangular, with anterior pair of closely set trichoid sensilla; seventh sternite with posterior margin slightly wider than anterior, and with anterior pair of closely set trichoid sensilla; eighth sternite narrower than seventh, also with posterior margin slightly wider than anterior. Genitalia ( Figs. 6–8 , 24 ): Gonocoxite with stout, rounded and densely pubescent mediobasal lobe, the length of the mediobasal lobe a little shorter than aedeagus; gonostylus arched and slender, gradually tapering from base to apex, approximately half length of gonocoxite, covered with a few setae and dense microtrichiae, a brushlike tuft of short setae located apicodorsally on the inner side, toothed apically; cerci separated deeply and broadly, rounded apically with a few long lateral setae; hypoproct as long as cerci, deeply emarginate, forming two slender, apically rounded lobes, each with a few short setae; aedeagus short, gradually tapered to apex.

Female abdomen ( Fig. 25 ): First through fifth tergites as in male except fourth and fifth tergites without lateral setae; sixth tergite 0.22–0.23 mm in length, 0.40–0.43 times as long as wide, slightly narrower than fifth, with posterior margins wider than anterior, and with an irregular but mostly single, posterior row of setae interrupted in the middle, uniformly covered with scales; seventh tergite sub-trapezoid in shape except for lateral indentations, darkly pigmented, 0.34–0.35 mm in length, 0.86–0.87 times as long as wide and much narrower than and 1.5–1.6 times length of sixth, with anterior pair of trichoid sensilla, scattered lateral and posterior scales, 0–2 pairs of lateral setae and with an irregular but mostly single, posterior row of setae interrupted in the middle; eighth tergite more strongly sclerotized than seventh, more deeply incised posteriorly than anteriorly, with two thin, shorter distal apodemes that extend beneath the seventh tergite, bare except for anterior pair of trichoid sensilla at distal third and the distal half with pigmented latitudinal sclerites; second through fifth sternites as in male; sixth sternite rectangular, with anterior pair of closely set trichoid sensilla, and with an irregular but mostly single, posterior row of setae, and covered with many scattered lateral and central setae and uniformly with scales; seventh sternite campaniform, highly sclerotized, and approximately as wide as and three times length of sixth, with anterior pair of closely set trichoid sensilla, uniformly covered with scales and with an irregular but mostly single, posterior row of setae interrupted in the middle. Ovipositor ( Figs. 13–16 , 25, 26 ) protrusible and extraordinarily long; eighth segment with the basal half inflated and with the distal half cylindrical; ninth segment stiff, bilaterally flattened, 1.8–1.9 mm in length, 11.0–13.0 times as long as wide, tapered sharply to a point apically, sparse microtrichiae present subapically; cerci fused, tapering to pointed, slightly upcurved apex, covered with sparse microtrichiae midventrally and elsewhere with short setae and microtrichiae, 5.1–5.2 times as long as wide, wider than and as long as the end of ninth segment; hypoproct cylindrical and extraordinarily slender, covered with sparse microtrichiae, approximately 2/3 length of cerci.

Pupa. Exarate, enclosed with white cocoon. Colour orange. Length 2.7–3.1 mm, female pupa longer than male. Cephalic region ( Fig. 18 ): antennal bases swollen with two pairs of rounded prominences protruding anteriorly that pupa uses in forcing the way out of galls for eclosion; frons with marginal thickening; cephalic seta filiform, 0.045–0.046 mm in length; 2 pairs of setose lower facial papillae; 3 pairs of lateral facial papillae, 1 pair setose. Thorax ( Fig. 18 ): prothoracic spiracle elongate, pointed apically, gradually thinner to apex, a little curved, 0.165–0.170 mm in length, 8.75–8.76 times as long as wide. Abdomen: segments 1–9 covered with many short spines dorsally; segments 2–8 densely with many short spines ventrally and with abdominal spiracles relatively long and pointed apically; segments 8–9 specialized to cystidium.

Larva. First instar: body hyaline, body length 0.4–0.5 mm, elliptic cylindrical, flat ventrally, convex dorsally.

Last instar ( Fig. 20 ): body colour saffron, body length 2.5–3.5 mm, elongate ovoid. Antennae ( Fig. 17 ) tapered, 2.1–2.2 times as long as wide; 3 pairs of dorsal papillae each with seta present on thoracic segments and abdominal segments 1–7, 1 pair of dorsal papillae on abdominal segment 8, each with minuscule seta; spiracles present on prothorax and abdominal segments 1–8; 1 pair of sternal papillae and 1 pair of inner pleural papillae present on each thoracic segment; 2 pairs of outer pleural papillae on each thoracic segment, each with minuscule seta; 3 pairs of lateral papillae in each of two clusters, two of each with setae, on either side of each thoracic segment; sternal spatula 0.09–0.13 mm in length ( Fig. 19 ) with one pair of anterior teeth separated by U-shaped emargination, the stalk constricted at posterior third, less pigmented than teeth, 1.22–1.23 times as long as wide in the middle; 2 pairs of pleural papillae present on abdominal segments 1–8, each with minuscule seta; 2 pairs of anterior ventral papillae without seta and 1 pair of posterior ventral papillae without seta present on abdominal segments 1–7, 2 pairs of posterior ventral papillae without seta on abdominal segment 8; 3 pairs of terminal papillae each with minuscule seta present on abdominal segment 9.

Egg. Spindleform, hyaline, smooth with one end subacute and the other blunt, 0.5 mm in length, approximately 10.0 times as long as wide.

Gall. The galls ( Fig. 27 ) are inconspicuously swollen branchlets of Phyllostachys propinqua McClure ( Poaceae ) with one or more conspicuous white, tear-shaped membranes covering the presumptive exit hole of every chamber. Each affected branchlet has 1-8 galls in a line. Galls consist of an elongate-ovoid chamber inhabited by a single larva.

Biology. Zeng et al. (2009) reported the biology of P. phyllostachys (as Procystiphora sp.) as follows: one generation occurs per year in Tianjin, China. First instars forage on newly sprouted branchlets in trail to form larval chambers. Later larvae sink into the branchlets by foraging plant tissue inside, with the outside of branchlets growing to form chambers with tear-shaped exits. Mature larvae begin to spin white cocoons within galls in mid May, start to pupate in early October and overwinter in the galls. Adults emerge from galls in early April through the tear-drop shaped exits. Females then lay eggs on the newly sprouted branchlets after mating. Three species of parasitoids have been found, namely Pediobius sp. (endoparasitoids), Eurytoma setigera Mayr and Eupelmus urozonus Dalman (ectoparasitoid). Detailed descriptions of the parasitoids are provided by Zeng et al. (2009).

Type material. Holotype male: China, Tianjin: Nankai District, Tianjin Water Park (39.089°N, 117.161°E), 5.XII.2006 (pupa in galls), 16.I.2007 (reared in lab), Yan Zeng leg., altitude 3 m, deposited in NKUM. Paratypes: 1 male and 2 females, same data as holotype; 2 males and 2 females, same place with holotype, XII.2007 (reared in lab), Yan Zeng leg.; 2 males and 2 females, China, Tianjin: Nankai District, Nankai University (39.101°N, 117.165°E), 8–14.IV.2007, Kelong Jiao leg., altitude 3 m, Malaise trap; 62 males and 12 females, ibid, 5– 14.IV.2008, Kelong Jiao leg., Malaise trap; 2 pupae and 1 mature larva, ibid, X.2007, Yan Zeng leg.; 3 mature larvae, ibid, 14.VI.1999, Wenjun Bu leg.; 2 mature larvae, ibid, V.2007, Yan Zeng leg..

Etymology. The specific name phyllostachys is the name of the host genus and is a noun in apposition.

Remarks. This new species is characterized by the uniqueness of female post-abdomen. It is the only known Procystiphora with the peculiarly shaped eighth tergite with its two apodematous extensions and the pointed apices of both the ninth segment and cerci. The Chinese species is also distinguishable from the four other congeners by having male gonocoxite and gonostylus slender, male antenna with 18 and female antenna with 18–20 flagellomeres.

Procystiphora phyllostachys and P. uedai are the only species so far known to utilize bamboos as hosts. However, P. phyllostachys differs from P. uedai by having gonocoxite with apically rounded, long mediobasal lobe (not triangular lobes) and slender lobes of hypoproct (not stout ones). P. phyllostachys is also similar to P. g e r a rd i in the shape of inconspicuously swollen galls, while the other three congeners induce conspicuously swollen galls.

Male hypoprocts of P. phyllostachys , P. uedai and P. g e r a rd i are with lobes rounded apically, while the other two have lobes pointed apically.

In immature stages, P. phyllostachys is similar to P. uedai by having the larval terminal segment with 3 pairs of terminal papillae and 1 of 3 pairs of pupal lateral facial papillae setose. However, P. phyllostachys , as well as P. gerardi , is distinguishable from P. uedai by having pupal frons with 2 pairs of lower facial papillae (not 1 pair). In addition, P. phyllostachys is different from P. g e r a rdi that has 4 pairs of terminal papillae ( Meyer 1984).

Figures

FIGURES 21 – 27. Procystiphora phyllostachys sp. nov. (photomontaged by Auto-montage Essentials software). 21, Male head (anterior view). 22, Male antenna (anterior view, acid fuchsin staining). 23, Female antenna (anterior view, acid fuchsin staining). 24, Male genitalia (dorsal view). 25, Female abdomen, fourth segment to end (dorsolateral view). 26, End of ovipositor (lateral view, acid fuchsin staining). 27, Two galls of Procystiphora phyllostachys sp. nov. in one branchlet of Phyllostachys propinqua McClure.

FIGURES 1 – 8. Procystiphora phyllostachys sp. nov., male: 1, Palpus. 2, 18 th flagellomere (ventral view). 3, Wing. 4, 3 rd flagellomere (ventral view). 5, Fore acropod (lateral view). 6, Cerci and hypoproct (dorsal view). 7, Cerci (ventral view). 8, Genitalia (dorsal view, cerci and hypoproct removed).

FIGURES 9 – 15. Procystiphora phyllostachys sp. nov., female: 9, Palpus. 10, 3 rd flagellomere (ventral view). 11, Terminal flagellomere (ventral view). 12, Fore acropod (lateral view). 13, Seventh segment (ventral view). 14, Seventh segment to eighth of abdomen (dorsal view). 15, Seventh and eighth tergites (dorsal view).

FIGURES 16 – 20. Procystiphora phyllostachys sp. nov. 16, End of ovipositor (lateral view). 17, Head of mature larva (ventral view). 18, Frontal area and prothoracic spiracles of pupa (lateral view). 19, Sternal spatula and adjacent papillae of mature larva (ventral view). 20, Mature larva (ventral view).