Polistes (Polistella) delhiensis Das and Gupta , 1989

Nguyen, Lien Thi Phuong, Nguyen, Cuong Quang & Bozdoğan, Hakan, 2018, Additions to knowledge of the paper wasp Polistes delhiensis Das and Gupta, 1989 (Hymenoptera: Vespidae: Polistinae) from Vietnam with description of the male and nest, Zootaxa 4462 (1), pp. 145-150 : 146-149

Polistes (Polistella) delhiensis Das and Gupta, 1989 ( Figs 1–12 )

Polistes delhiensis Das and Gupta, 1989: 63 , female, Delhi [ India], [holotype in Zoological Survey of India, Calcutta (now Kolkata)]. Polistes delhiensis was described by Das and Gupta (1989) based on a single female specimen (holotype) from Delhi [ India], with the exact date of collection and collector’s name not given (except for “Gupta”). In Vietnam, this species has been recorded from Son La, Ha Giang, Bac Kan, Phu Tho, Hoa Binh, Vinh Phuc in the northern part of the country ( Nguyen & Pham, 2011; Nguyen & Kojima, 2014; Nguyen & Carpenter, 2016). A pre-emergence stage nest with 19 cells of this species was described from Bac Kan in the northern part of Vietnam ( Nguyen & Kojima, 2014). No record of this species from southern part of the country was listed.

Nguyen and Carpenter (2016) stated that Das and Gupta (1989) described the species from India with the clypeus reddish-brown and basal margin broadly black, and all examined specimens from Vietnam have the clypeus reddishbrown and two spots at apical lateral corners yellow ( Fig. 1 in Nguyen & Carpenter, 2016). In the present study, specimens from the southern part of Vietnam with a brighter color form of the clypeus were examined. They have the clypeus yellow with basal margin narrowly dark brown ( Fig. 1 ) (like sp. 1 in Nguyen et al., 2018) or largely yellow with basal margin broadly and lateral margins narrowly dark brown (like sp. 2 in Nguyen et al., 2018). The body coloration of the two forms is almost identical: ground color dark brown, following parts yellow: faint band along inner eye margin extending from bottom of frons to middle of eye emargination, narrow band along eye margin in dorsal part of gena, flagellomeres beneath, narrow band along pronotal carina, anterior transverse band on scutellum (absent in some specimens from southern part) and metanotum, longitudinal line along lateral faces of propodeum (reduced in some specimens from southern part), valvula, narrow band at apical margin of terga 1 (extending laterally toward its base) and 2-4 (absent in some specimens from southern part); following parts black: area around ocelli, band at apical margin of mesoscutum, posterior face of propodeum (only lower part of propodeum in some specimens from northern part), band at base of terga 2-4 ( Fig. 2, 3 ).

The morphological characters of the two color forms of P. delhiensis were examined, and the two forms are quite similar. Recently, the molecular analysis also indicates that Polistes sp.1 and Polistes sp.2 (bright color form) and P. delhiensis (darker color form) have short genetic distances between them (about 0.013 between P. delhiensis and Polistes sp. 2 and 0.026 between Polistes sp. 1 and a clade of P. delhiensis and Polistes sp. 2 ( Fig. 1 in Nguyen et al., 2018). Therefore, it can be concluded that two color forms are conspecific with P. delhiensis .

In this study, the male of the darker color form and a fully- developed nest of the bright color form of P. delhiensis are described here for the first time.

As described below, the male is similar to the female both in structure and coloration except for some characters.

Material examined. 1 ♂ ( IEBR), Giang Chi, Sinh Long , Na Hang , Tuyen Quang, 14.ix.2017, Insect Systematic Department ; 1 ♀ ( IEBR), Kim Hy NR, Lang San, Na Ri , Bac Kan, 22°14'N 106°5'E, 3.vi.2014, Nguyen Thi Phuong Lien, Nguyen Dac Dai, Tran Dinh Duong ; 8 females ( IEBR), Nest #Vietnam-TN-2012-P-04; Ngoc Linh NP, Quang Nam, 16.vii.2012, Hoang Van Chung ; 1 ♀ ( IEBR), Ta Dung NR, Dak Som, Dak Glong , Dak Nong, 11°50'16''N 107°59'17.4''E, 790 m, 17.iv.2015, Nguyen Thi Phuong Lien, Nguyen Quang Cuong, Tran Thi Ngat.

Description. Male. (male hitherto unknown), (female characters in square brackets). Body length 10.5 mm [10.7– 11 mm]; fore wing length 11 mm [11.8–12.5 mm].

Head in frontal view ( Fig. 4 ) 1.2 times [1.1 times] as wide as high. Vertex almost flat between ocelli; POD:OOD =1:2.6 [1:2.4]; POD 0.7 times [0.9 times] Od ( Fig. 5 ). Eye much more strongly swollen laterally than in female; inner eye margins 1.5 times [1.1 times] further apart from each other at vertex than at clypeus. Gena narrow [more or less wide], in lateral view ( Fig. 6 ) 0.5 times [0.8 times] as wide as eye; weakly raised blunt ridge present, running along posterior margin of eye, reduced at mid-dorsal part in both sexes. Clypeus in frontal view ( Fig. 4 ) higher than wide, 0.7 times as wide as high, apical margin pointed apically in both sexes ( Fig. 4 ); in lateral view slightly convex at basal twothirds [weakly swollen anteriorly]; surface with dense short golden hairs [surface with scattered deep large punctures each bearing sharply pointed golden bristle]. Antenna ( Fig. 7 ) with slenderer flagellum than in female; scape short and thick, 2.8 times [3.3 times] as long as its maximum width; flagellomere 1 as long as [much longer than] length of flagellomeres 2 and 3 combined; flagellomeres 4–9 each longer than wide [wider than long]; terminal flagellomere slightly curved [bullet shaped], 3 times longer than [1.2 times] its basal width.

Mesosoma as in female. Pronotal carina sharply raised, produced into thin lamella dorsally, slightly sinuate laterally, reaching ventral corner of pronotum. Mesoscutum convex, about as long as wide between tegulae; anterior margin broadly rounded. Scutellum convex, disc flat. Metanotum weakly convex. Propodeum short; posterior face narrowly (about one sixth the maximum width of propodeum) excavated medially, smoothly passing into lateral faces; propodeal orifice elongate, about 2.1 times as long as wide (measured at widest part), somewhat narrowed in dorsal half. Fore wing with dark spot at apex of marginal cell, jugal lobe much reduced.

Metasoma except terminal two segments as in female. Metasomal tergum 1 nearly × as long as its apical width, and nearly 1.8 × as long as its height (less than 1.5 × in almost all other Polistella species except P. meadeanus which has a very long petiole, and P. adsimilis with a long petiole), in lateral view gradually swollen dorsally just behind basal slit for reception of propodeal suspensory ligament. Sternum 2 in lateral view gradually swollen ventrally. Metasomal sternum 7 depressed medially, without tubercle.

Body surface sculpture as in female, except for densely-setose clypeus. Mandible with scattered shallow punctures. Frons with shallow indefinite punctures. Vertex and gena smooth; area around ocelli smooth; ventral third of gena with scattered shallow punctures. Pronotum with shallow large punctures. Mesocutum with punctures similar to those on pronotum; punctures on scutellum stronger, and punctures on metanotum weaker than those on mesoscutum. Mesepisternum with dense coarse well-defined punctures in posterodorsal part, smooth in anteroventral part; border between posterodorsal and anteroventral parts indistinct. Dorsal metapleuron almost smooth; ventral metapleuron with sparse shallow punctures. Propodeum with strong transverse striae. Metasomal segments with minute punctures.

Color. Similar to female [dark brown, following parts yellow: two spots at margin corner of clypeus (sometimes absent in dark form), faint band along inner eye margin extending from bottom of frons to middle of eye emargination (not clear in the dark form), narrow band along eye margin in dorsal part of gena, flagellomeres beneath, narrow band along pronotal carina and pronotal margin at dorsal part, anterior transverse band on metanotum (faint in bright form), longitudinal line along lateral faces of propodeum, valvula, a band at apical margin of tergum 1 (extending laterally toward its base) and narrow band at apical margin of terga 1–4) but more extensively marked with yellow as follows: lateral margins of clypeus, mandible except for small basal black spot, antennal scape beneath; lateral margin of terga 1- 4 without yellow narrow band.

Male genitalia. Generally similar to that of P. adsimilis ( Nguyen and Carpenter, 2016) . Digitus in inner aspect of paramere ( Fig. 9 ) 3.2 × as long as wide (measured at widest part), distinctly swollen near base, gradually narrowed apically to mid-length, then slightly swollen towards the rounded apex. Aedeagus ( Figs 10, 11 ), penial valves 0.9 × as long as basal apodeme (note that this number is 1.0 (extracted from figure 26) in P. adsimilis , not 1.2 as mistakenly mentioned in Nguyen and Carpenter (2016)), in ventral view narrowest near mid-length, nearly straight from mid-length then strongly swollen and distinctly produced laterally near proximal margins, in lateral view slightly thickened in proximal one fourth and with dorsal margin strongly sinuate, with proximoventral corner produced into acute angle ( Fig. 10 ); ventral margin of penial valves finely serrated along entire length.

Nest. One fully-developted nest (Nest#Vietnam-TN-2012-P-04) ( Fig. 12 ) with eight females collected by Hoang Van Chung at Ngoc Linh National Park in Dak Lak province of the southern part of Vietnam was examined. The nest had 89 cells, with 16 pupae as immatures, without eggs and was attached to a thin branch of a shrub about 1.2 m above the ground. The structural and morphological characters are as follows: Comb tough, pliable “paper”-like in texture, more or less uniformly brown cell wall, subcircular (about 32 mm x 27 mm) in view from side of cell opening, expanded concentrically from the single petiole, with surface corresponding to cell bottom slightly convex. Petiole single, central, attached to the border between bottoms of the first four cells, 3.8 mm long and 0.9 x 1.2 mm thick at the mid-length, with thin central core of plant fibers, enlarged strictly with adult oral secretion, dark brown and lustrous, secretion coat expanded on comb back around the petiole and on substrate in about 3 mm x 4 mm thin film. Cells generally arranged in regular rows, hexagonal at open end when surrounded by other cells, with free margins rounded; each cell expanded towards open end, 3.7 mm (range 3.2 – 4.4 mm; n=10) wide at open end, 2.5 mm (range 2.2 – 2.8 mm; n=10) wide at

bottom and 11.3 (range 10.3 – 12.7 mm; n=10) mm deep in full grown cells. Cocoon caps slightly domed beyond rim of cell, pale greenish-yellow.

Distribution. India; Vietnam ( Nguyen & Carpenter, 2016).

Figures

FIGURES 1–3. Polistes delhiensis, female. 1. Clypeus in frontal view of the brighter form from the southern Vietnam. 2. Habitus of the brighter form from the southern Vietnam. 3. Habitus of the darker form from the northern Vietnam.

FIGURES 4–12. Polistes delhiensis, male. 4. Head, frontal view. 5. Vertex, dorsal view. 6. Head, lateral view. 7. Left antenna. 8. Habitus. 9–11. Genitalia. 9. Inner aspect of paramere with digitus and volsella. 10, 11. Aedeagus (10. Ventral and 11. Lateral view). Scale 1mm. 12. Nest.