Encarsia dianensis Li & Geng

Geng, Hui & Li, Cheng-De, 2016, Five new species of genus Encarsia Förster from China (Hymenoptera: Aphelinidae), Zootaxa 4162 (3), pp. 535-549 : 536-539

Encarsia dianensis Li & Geng , sp. nov.

Figs 1–8

Type material. Holotype. ♀ [on slide], ( NEFU), CHINA, Yunnan Province, Ruili City, Nanjingli Village, 26–27. IV. 2013, Xiang-Xiang Jin , Guo-Hao Zu , Chao Zhang , YPT.

Paratypes. 5♀ [on slides], CHINA, Yunnan Province, Xishuangbanna, Mengla County, Menglun Town , Nanxing , 12–14. II. 2014, Guo-Hao Zu , Zhong-Ping Xiong , YPT ; 2♀ [on slides], CHINA, Yunnan Province, Puer City, Manxieba Village, 17–18. IV. 2013, Xiang-Xiang Jin , Guo-Hao Zu , Chao Zhang , YPT. ( NEFU).

Diagnosis. Female. Length, mesosoma plus metasoma, 0.42–0.52 mm. Body entirely yellow to pale yellow, sometimes pronotum, petiole and T1 slightly brown. Antennal formula 1:1:3:3. Mid lobe of mesoscutum with 4 or 5 setae; each side lobe and axilla with 1 seta; placoid sensilla on scutellum widely separated; distance between anterior pair of scutellar setae distinctly greater than that between posterior pair. Fore wing 3.36–3.67× as long as wide, sparsely setose, with a large asetose area around stigmal vein; marginal fringe 0.77–0.97× as long as wing width. Tarsal formula 5:4:5. Mid tibial spur 0.79–0.84× as long as corresponding basitarsus. Petiole smooth. T7 2.2–2.38× as wide as long. Ovipositor slightly exerted, 0.58–0.7× as long as mid tibia; third valvula 0.5–0.6× as long as second valvifer.

Description. Female. Holotype. Length, mesosoma plus metasoma, 0.49 mm. Head and body, including ovipositor and legs entirely pale yellow; pedicel and flagellum pale brown, distal segments slightly darker. Wings hyaline, venation pale brown.

Head ( Fig. 1 ), in frontal view, 1.52× as wide as high, a little broader than mesosoma. Frontovertex 0.64× as broad as head width. Eyes with fine and transparent setae. Ocelli forming about an obtuse triangle, POL distinctly less than OOL. Stemmaticum reticulate. Mandible with two teeth and a truncation. Maxillary and labial palpi 1- segmented. Antennae inserted at level of lower margin of eyes. Distance between toruli about 0.5× distance from torulus to eye margin. Antennal formula, 1:1:3:3 (cf. Fig. 2 ); pedicel (P), 3 funicle segments (F1–F3) and 3 club segments (F4–F6) with the following ratios of length to width: P: 1.50, F1: 1.25, F2: 1.24, F3: 1.20, F4: 1.21, F5: 1.23 and F6: 1.57; relative lengths of segments P–F6 to length of F1: P: 1.50, F1: 1.00, F2: 1.05, F3: 1.20, F4: 1.45, F5: 1.60, and F6: 2.00; flagellum with the following numbers of longitudinal sensilla: F1: 0, F2: 0, F3: 1, F4: 2, F5: 3, F6: 3.

Mesosoma (cf. Fig. 3 ) 0.7× as long as metasoma. Mid lobe of mesoscutum and axillae reticulate. Mid lobe of mesoscutum with 4 setae, each side lobe of mesoscutum with 1 seta. Axilla with 1 short seta. Scutellum 2.19× as wide as long, and 0.64× as long as mid lobe. Distance between placoid sensilla on scutellum approximately 7× maximum width of a sensillum. Anterior pair of scutellar setae distinctly shorter than posterior pair, and distance between anterior pair 1.48× that between posterior pair. Endophragma long and rounded at apex, extending to middle of T2. Fore wing ( Fig. 4 ) 3.51× as long as wide, sparsely setose, with a large asetose area around stigmal vein; costal cell with 4 short setae in basal half; basal cell with 1 seta; submarginal vein with 2 setae; marginal vein 1.26× as long as submarginal vein, with 4 setae along anterior margin; marginal fringe 0.88 × as long as wing width. Tarsal formula 5:4:5, mid leg with last two tarsal segments fused but indicated by a transverse suture ( Fig. 5 ). Mid tibial spur 0.82× as long as corresponding basitarsus ( Fig. 5 ), and the latter 0.28× as long as mid tibia. Hind tibia 0.95× as long as mid tibia.

Metasoma ( Fig. 8 ) with petiole smooth. T1–T5 with scale-like reticulation laterally. T2–T7 with 1+1, 1+1, 1+1, 2+2, 1+2+1 and 4 setae, respectively. T7 2.38× as wide as long. Ovipositor ( Fig. 8 ) slightly exerted, apparently originating from middle of T5, 0.64× as long as mid tibia, and 0.5× as long as mid tibia and basitarsus combined. Third valvula 0.5× as long as second valvifer.

Male. Unknown.

Host. Unknown.

Variation. Length, mesosoma plus metasoma, 0.42–0.52 mm. Body entirely yellow to pale yellow, occasionally pronotum, petiole and T1 slightly pale brown. F1 1.13–1.46× as long as wide, and 0.64–0.95× as long as F2. F6 1.57–2.09× as long as wide. Number of longitudinal sensilla on F1–F 6 in two paratypes from Puer: F1: 0, F2: 1, F3: 2, F4: 3, F5: 3, F6: 3. Fore wing 3.36–3.67× as long as wide, marginal fringe 0.77–0.97× as long as wing width. Mid lobe of mesoscutum with 4 setae (5 in one paratype). Mid tibial spur 0.79–0.84× as long as corresponding basitarsus, and the latter 0.28–0.33× as long as mid tibia. Hind tibia 0.87–0.95× as long as mid tibia. Ovipositor 0.58–0.7× as long as mid tibia, and 0.45–0.55× as long as mid tibia and basitarsus combined. Third valvula 0.5–0.6× as long as second valvifer.

Etymology. Chinese: dian = Yunnan Province, which refers to the distribution of the species in the Yunnan Province of China.

Comments. In situations where the mid tarsi have the last two segments partly fused, but indicated either by a transverse suture or a distinct constriction, most (if not all) authors usually regarded the tarsi as 4-segmented. This includes Hill (1970) for E. africana (in his fig. 6), Polaszek et al. (2004) for E. dispersa (in their fig. 9B), Myartseva (2007) for E. flaviceps (in his fig. 13), Myartseva & Evans (2008) for E. florena (in their fig. 128), and Myartseva et al. (2012) for E. xilitla (in their fig. 3). Females of E. dianensis also have the last two tarsal segments of the mid leg partly fused and indicated by a transverse suture ( Figs 5, 6, 7 ), so we regarded it as 4-segmented.

Encarsia dianensis is placed in the E. cubensis -group ( Evans & Polaszek 1998) based on a 5:4:5 tarsal formula, fore wing with large asetose area around the stigmal vein, marginal fringe of the fore wing not longer than the maximum wing width, widely separated placoid sensilla on the scutellum, smooth petiole, 3-segmented antennal clava, F1 subquadrate and shorter than the pedicel, and a short and slightly exerted ovipositor. The E. cubensis -group currently contains 8 species worldwide ( Evans & Polaszek 1998; Myartseva et al. 2013). Our new species is easily separated from all the species of this group and related species by its entirely yellow head and pale body. In all other species of the group, the head and at least the anterior half of the mesoscutum are dark.

This species is closely related to E. hayati , but can be distinguished from the latter by the following combination of characters: antennal flagellum stout, as in Fig. 3 (vs slender, as in Fig. 10 ); distance between anterior pair of scutellar setae distinctly greater than that between posterior pair (vs distinctly less), placoid sensilla on scutellum widely separated (vs narrowly separated); ovipositor distinctly shorter than mid tibia (vs longer than), third valvula 0.5–0.6× as long as second valvifer (vs 0.35–0.36×).

If E. dianensis is regarded as having 5-segmented mid tarsi, it could be related to E. flavescens Huang & Polaszek because of having similar body color, fore wing with a bare strip along the wing margin beginning from stigmal vein and ending at about distal end of retinaculum and similar numbers of setae on the mid and side lobes of the mesoscutum, but can be distinguished from the latter by: marginal fringe of fore wing long, 0.77–0.97× as long as disc width (vs 0.47×); placoid sensilla on scutellum separated by 7× maximum width of a sensillum (vs 3– 4×); ovipositor very short, 0.45–0.55× as long as mid tibia and basitarsus combined (vs 1.07×).

Figures

FIGURES 1 – 3. Encarsia dianensis sp. nov., holotype (except Figs 2, 3) ♀: 1, head, frontal view; 2, antenna (paratype); 3, mesosoma (paratype). Scale bars = 50 µm.

FIGURES 4 – 8. Encarsia dianensis sp. nov., holotype (except Figs 6, 7) ♀: 4, fore wing; 5, mid tibial spur and tarsi; 6, 7, mid tibial spur and tarsi (two paratypes); 8, metasoma. Scale bars = 50 µm.

FIGURES 9 – 16. Encarsia hayati sp. nov., holotype ♀: 9, head, frontal view; 10, antenna; 11, mesosoma; 12, fore wing; 13, mid tibial spur and tarsi; 15, sculpture on petiole; 16, ovipositor; paratype ♀: 14, mid tibial spur and tarsi. Scale bars = 50 µm.