wasps

Handru, Alan, Nugroho, Hari, Saito-Morooka, Fuki, Ubaidillah, Rosichon & Kojima, Jun-Ichi, 2020, Eusocial wasp fauna of Sulawesi Island, the central island of Wallacea (Hymenoptera: Vespidae; Polistinae, Vespinae), Zootaxa 4885 (4), pp. 541-559 : 542-543

Key to species of the eusocial wasps occurring in Sulawesi Island

The present key is applicable to both females (“queens” and “workers”) and males unless the sexes are specified. Because of uncertainty of species identity and/or uncertainty of their establishment in Sulawesi Island as mentioned in “Taxonomic accounts and notes on distribution”, Ropalidia crassa van der Vecht, 1941 , R. jacobsoni (du Buysson, 1908) and R. variegata ( Smith, 1852) , are not included in this key. In addition to the figures given in this paper, the figures that can be referred to are available in van der Vecht (1941, 1962, and 1966), Archer (1989), Kojima (1999), Kojima et al. (2002) and Carpenter and Nguyen (2003).

1. Hind coxa with dorsal longitudinal carina on posterior face ( Fig. 13 in Carpenter and Nguyen, 2003). Hind wing without jugal lobe. Metasoma sessile; T1 with anterior abrupt declivity ( Figs. 1, 3–4 ; Figs. 14–15 in Carpenter and Nguyen, 2003)....................................................................................... 2, Vespinae , genus Vespa

- Hind coxa without carina (Figs. 38–39 in Carpenter and Nguyen, 2003). Hind wing with jugal lobe. Metasoma variable in shape, subsessile or petiolate ( Figs. 8, 11, 13 , 17, 19–20, 22–25; Figs. 16–18 in Carpenter and Nguyen, 2003)...................................................................................................... 5, Polistinae

2. Female clypeus with bluntly triangular tooth on each side of ventromedian excision ( Fig. 27A in Archer, 1989). Body covered with stiff hairs. T1 almost entirely colored orange (T1 and 2 each with apical yellowish orange band) ( Fig. 1 )........................................................................................ Vespa tropica ( Linnaeus, 1758)

- Female clypeus with short, broadly rounded lobe on each side of ventromedian excision ( Fig. 6 ). T1 mostly black ( Figs. 2–3, 5 ) or with dorsal face nearly entirely orange yellow ( Fig. 4 )................................................... 3

3. Pronotal carina widely interrupted by pronotal fovea ( Fig. 29B in Archer, 1989). Pretegular carina extending ventrally to the level of middle of pronotal tubercle ( Fig. 29B in Archer, 1989). T4 with broad apical yellowish-brown band ( Figs. 2–3 ).............................................................................. Vespa velutina Lepeletier, 1836

- Pronotal carina only narrowly interrupted by pronotal fovea ( Fig. 29A in Archer, 1989). Pretegular carina extending ventrally beyond the level of ventral margin of pronotal tubercle ( Fig. 29A in Archer, 1989)................................. 4

4. T1 relatively long, more than 2/3 as long as T2 length in dorsal view. Head and mesosoma black, sometimes with ferruginous or dull red markings, never with yellow markings. T1 with dorsal face largely orange yellow and T2 entirely orange yellow ( Fig. 4 )......................................................................... Vespa affinis ( Linnaeus, 1764)

- T1 short, transverse, about half as long as T2 length in dorsal view. Body black, with following parts cream-yellow: apical margin of clypeus, metanotum, apical band of T1 ( Figs. 5–6 )............................. Vespa fervida Smith, 1859

5. First metasomal segment subsessile, not petiolate ( Figs. 8, 10–11, 13 ); S1 bluntly angled basally ( Fig. 8 ).............................................................................................. 6, Polistini , genus Polistes

- First metasomal segment in most cases petiolate ( Figs. 17, 19–20, 22–23 ); S1 flat throughout.............. 9, Ropalidiini

6. Clypeus not produced dorsally beyond the level of anterior tentorial pits ( Fig. 7 ). Pronotal fovea present. Mesepisternum with dorsal groove, without epicnemial groove. Body brown to dark brown; T1 and S1 brown or blackish brown ( Figs. 7–8 )............................................................... Polistes (Gyrostoma) tenebricosus Lepeletier, 1836

- Clypeus produced dorsally beyond the level of anterior tentorial pits ( Figs. 9, 12, 14 ). Pronotal fovea, epicnemial carina and dorsal groove, all absent. Body color and markings similar to P. tenebricosus ( Figs. 9–10 ; P. sagittarius ) or much brighter ( Figs. 11–14 )............................................................................ 7, subgenus Polistella

7. Larger species; forewing length 15-20 mm. Gena wide, in profile about 0.7-0.9 times as wide as eye in female ( Fig. 10 ). Fore wing without a dark spot. Propodeum with strong transverse striae. Body ferruginous to dark brown, sometimes T1 and/or T2 with orange-yellow or dark brownish bands ( Fig. 8 ).................. Polistes (Polistella) sagittarius de Saussure, 1853

- Smaller species, forewing length 11-14 mm. Gena about 0.6-0.7 times as wide as eye in female ( Figs. 11, 13 ). Fore wing with apical dark spot ( Figs. 11, 13 ). Propodeum shallowly excavated medially and with weak transverse striae. Body with extensive yellow and reddish-brown markings ( Figs. 11–14 )............................... 8, Polistes (Polistella) stigma group

8. Hind tarsal claw asymmetrical ( Fig. 15 ). Clypeus reddish-brown in basal half and yellow in apical half, with a small pair reddish-brown spots on the apex, scattered punctures, rather deep punctures ( Fig. 12 ). T1-4 with apical yellow bands; S2-4 with broad apical yellow bands ( Fig. 11 )..................................... Polistes (Polistella) celebensis Selis, 2018

- Hind tarsal claws more or less symmetrical ( Fig. 16 ). Clypeus entirely yellow, with shallow punctures ( Fig. 14 ). T4 without apical yellow band, S2 with posterolateral spots and S3 with narrow apical yellow band ( Fig. 13 )................................................................................ Polistes (Polistella) stigma stigma ( Fabricius, 1793)

9. Pronotal fovea, dorsal groove of mesepisternum, pretegular carina, all present ( Fig. 17 ; Fig. 39 in Carpenter and Nguyen, 2003). T2 and S2 not fused, overlapping ( Fig. 17 ). Body mostly brown with yellow markings ( Figs. 17–18 ; Fig. 12 in van der Vecht, 1966).................................................................. Parapolybia varia ( Fabricius, 1787)

- Pronotal fovea, dorsal groove of mesepisternum, pretegular carina, all absent ( Figs. 19–20, 22–25 ; Fig. 38 in Carpenter and Nguyen, 2003). T2 and S2 fused, leaving at most suture ( Figs. 19–20, 22–24 )...................... 10, genus Ropalidia

10. Suture between T2 and S2 more or less distinct, visible from base to apex of the segment ( Fig. 19 ; Fig. 19 in van der Vecht, 1941). First metasomal segment elongate, flask-shaped, more than twice as long as wide in dorsal view. T1 laterally rufous, rarely with yellow spots at base; S2 rarely with yellow spots ( Fig. 19 )............. Ropalidia mathematica (Smith, 1860)

- Suture between T2 and S2 indistinct, hardly visible in posterior part ( Figs. 20, 22–24 ). First metasomal segment shorter, less than twice as long as wide in dorsal view ( Fig. 21 )......................................................... 11

11. Propodeum with paired basal longitudinal carinae, running from posterolateral angles of metanotum ( Fig. 21 ).......... 12

- Propodeum without carinae............................................................................ 13

12. In dorsal view head narrower than mesosoma excluding tegulae; female gena narrow, less than half as wide as eye in lateral view ( Fig. 22 ). Apical margin of T2 and S2 armed with short, blunt teeth ( Fig. 22 ; Fig. 9 in van der Vecht, 1941). Body coarsely punctate, clypeus with scattered punctures......................................... Ropalidia pilosa (Smith, 1858)

- In dorsal view head wider than mesosoma excluding tegulae; female gena as wide as eye in lateral view ( Fig. 20 ). Apical margin of T2 and S2 without teeth ( Fig. 20 ). Body not strongly punctate, but clypeus densely punctate............................................................................................ Ropalidia marginata ( Lepeletier, 1836)

13. T1 elongate ( Fig. 23 ), in dorsal view gradually swollen posteriorly and narrowed near apical margin. Second metasomal seg-ment in lateral view obliquely cut off apically, T2 longer than S2 ( Fig. 23 ). Male terminal antennal flagellomere bullet-shaped ( Fig. 3 in Kojima, 1999)................................................... Ropalidia impetuosa (Smith, 1860)

- T1 short ( Figs. 24–25 ), in dorsal view gradually swollen posteriorly toward apical margin. Male terminal antennal flagellomere slightly curved...................................................................................... 14

14. T1 gradually swollen dorsally from the posterior end of basal slit for the ligament connecting propodeum and T1, then strongly widened laterally as long as less than 1.5 times high (Fig. 43 in van der Vecht, 1941). Median excavation of propodeum rather shallow............................................................. Ropalidia cyathiformis ( Fabricius, 1804)

- T1 barely petiolate basally, in lateral view abruptly swollen dorsally at the posterior end of basal slit to receive propodeal liga-ment ( Figs. 24–25 ). Median excavation of propodeum rather wide and deep................ 15, Ropalidia plebeja group

15. T 1 in lateral view strongly swollen dorsally just behind basal slit to receive propodeal ligament, with dorsal surface relatively broadly curved down toward posterior margin from its highest point, in dorsal view distinctly narrowing posteriorly near pos-terior margin ( Fig. 24 ; Figs. 8–9 in Kojima et al., 2002). In female, POD less than 3 times Od ( Fig. 13 in Kojima et al., 2002); gena in lateral view less than 0.9 times as wide as eye ( Fig. 24 ; Fig. 2 in Kojima et al., 2002)............................................................................................... Ropalidia plebeja (de Saussure, 1862)

- T 1 in lateral view less strongly swollen dorsally at posterior margin, with dorsal face broadly and weakly curving down toward posterior margin from its highest point, in dorsal view barely narrowing posteriorly ( Fig. 25 ; Figs. 55–56 in Kojima et al., 2002). In female, POD more than 3 times Od (Fig. 50 in Kojima et al., 2002); gena in lateral view nearly as wide as eye ( Fig. 25; Fig. 49 in Kojima et al., 2002)..................................... Ropalidia celebensis (van der Vecht, 1941)

Figures

FIGURES 7–16. ♀ of Polistes species. 7–8. P. tenebricosus. 9–10. P. sagittarius. 11–12, 15. P. celebensis. 13–14, 16. P. stigma. 7, 9, 12, 14. Head, frontal view, an arrow in 7 and 9 indicates anterior tentorial pit. 8. First two metasomal segments, lateral view, an arrow indicates basal angle of S1. 10, 11, 13. Habitus, lateral view, 15–16. Hind tarsal claws. Scale line 1 mm.

FIGURES 1–6. ♀ of Vespa species. 1. V. tropica. 2–3. V. velutina. 4. V. affinis. 5–6. V. fervida. 1–5. Metasoma (1, 3–5. Lateral view, 2. Dorsal view). 6. Head, frontal view, arrows indicate apical teeth.

FIGURES 26–29. Maps showing distribution records of Sulawesian eusocial wasps. 26. Vespa (four species). 27. Polistes (four species). 28. Ropalidiine species non-endemic to Sulawesi I. (five species). 29. Ropalidia species endemic to Sulawesi I. (three species).

FIGURES 17–25. ♀ of Ropalidiini species. 17–18. Parapolybia varia. 19. Ropalidia mathematica. 20–21. R. marginata. 22. R. pilosa. 23. R. impetuosa. 24. R. plebeja. 25. R. celebensis. 17, 19–20, 22–24. Habitus, lateral view. 18. Head, frontal view. 21. Posterior part of mesosoma and T1, dorsal view, an arrow indicates paired basal carina of propodeum. 25. Head, mesosoma and T1, lateral view.