Nisitrus vittatus (Haan, 1942)

Robillard, Tony & Tan, Ming Kai, 2013, A Taxonomic Review Of Common But Little Known Crickets From Singapore And The Philippines (Insecta: Orthoptera: Eneopterinae), Raffles Bulletin of Zoology 61 (2), pp. 705-725 : 707-712

Nisitrus vittatus (Haan, 1942)

( Figs. 1–9 )

Gryllus (Platydactylus) vittatus De Haan, 1842: 234

Nisitra vittata – Chopard, 1940: 199

Nisitrus vittatus – Saussure, 1878: 511 > Nomen novum for Nisitra Walker. Chopard, 1968: 352 ; Otte, 1994: 67; Tan, 2012: 4; Tan et al., 2012: 66. Robillard & Desutter-Grandcolas, 2004a: 276; 2004b:578; 2004c: 304; 2006: 644; 2011: 637> phylogeny and acoustic evolution. Robillard et al., 2007: 1265 > acoustics. Robillard & Desutter-Grandcolas, 2008: 67> Nisitrini tribe. Desutter-Grandcolas et al., 2010: 616 > cerci evolution. Nattier et al., 2011: 2201 > phylogeny and molecular dating. Eades et al., 2012 > Orthoptera species file online. Robillard et al., 2013: 2002 > mechanism of stridulation.

Discussion. — The initial type series of Nisitrus vittatus ( Haan, 1842) consisted of male and female specimens from Padang (Sumatra, Indonesia), supposed to be located in Leiden museum. The types were however not found in this museum in 2006 (T. Robillard, pers. obs.), with no record mentioning them as loaned (R. De Vries, curator of the Orthopteran collection in RMNH, Leiden, pers. comm.; confirmation in 2007). Specimens possibly belonging to the original type series were also searched for in the collections of several other museums where they might be (Paris, London, Vienna, Basel), but none could be found. Although vague, the original description may not correspond to others species of the genus known from Sumatra ( N. sumatrensis (Rhen, 1909) , N. insignis Saussure, 1878 ): the vertex is yellow with a black median pattern in the type of N. insignis (T. Robillard, pers. obs.; BMNH, 2004) and in the description of N. sumatrensis , while it is black in Haan’s (1842) description. The description however matches a series of specimens from the South of Sumatra (Lampung province), which are themselves very similar to the Nisitrus commonly found in Singapore and Malaysia (Peninsular). We thus use specimens from this area to redescribe formally and define a neotype series for the species N. vittatus , the most common species of the genus, upon which to base future description or revision work about Nisitrus .

Material examined. — Neotype (male): Indonesia, Lampung Province: male ( RMNH), Wai Lima, Z. Sum. [South Sumatra], Lampongs (N°40), coll. Karny & Siebers, Nov.–Dec.1921.

Paraneotypes (3 males, 10 females): Indonesia, Lampung Province: 2 females (N°183, 108) ( MNHN-ENSIF 3200-3198); 1 female (N°48) ( ZRC), same information as neotype; 1 male (N°422), identified Nisitra vittata Haan by L. Chopard, and Nisitrus vittatus Haan by T. Robillard (2004) ( MNHN-ENSIF 1742), Wai Lima, Z. Sum. [South Sumatra], Lampongs (N°40), coll. Karny, Nov.–Dec.1921. 1 male ( MNHN-ENSIF 1714), 1 male ( ZRC), Pahoe, Djambi exp. 1925 (No3) [Jambi = South Sumatra], coll. O. Posthumus, 26 Oct.[1925]; 1 female (No1) ( RMNH), 23 Oct.[1925]; 1 female (No2) ( MNHN- ENSIF 3199), 22 Oct.[1925], 1 female (No5) ( MNHN-ENSIF 1723), 28 Oct.[1925]; 1 female ( MNHN-ENSIF 3201), S. Sumatra, 600 m, S. W. Lampongs, Mt. Tanggaamues, coll. Giesting, Lieftinck & Toxopeus, Dec.1934; 1 female ( MNHN-ENSIF 3202), S. Sumatra, Lalembang, Soeban Djerigi, coll. Soekarno, 15 Jun.1933. 1 female ( MNHN-ENSIF 3203), Damm[?] Muntok Banka, 25 Nov.[19]23. 1 female ( MNHN-ENSIF 3204), Pedada-B Lampongs, Jan.1922.

Other material examined: Singapore: 1 male (TR9), day, call recording ( MNHN-ENSIF3102 ), Bukit Timah , [summit], 01°21'16.2"N, 103°46'35.9"E, 120 m, coll. T. Robillard, 29 Jun.2009 ; 1 male (TR1), day, on leaf (h = 40 cm) ( MNHN), 10 Jun.2011 ; 1 male (TR3), day, call recording ( MNHN-ENSIF3136 ), Bukit Timah , près de l’entrée de la réserve [near entrance], 01°21'06.7"N, 103°46'45.2"E, 92 m, coll. T. Robillard, 11 Jun.2011 ; 1 male (TR26), night, at rest on plant ( MNHN), Bukit Timah Nature Reserve , Hindhede trail, 01°20'57.1"N, 103°46'33.6"E 68 m, coll. T. Robillard, 20 Jun.2011 ; 2 males (TR29-30), day, on plant (h = 2 m), call recording ( MNHN-ENSIF2742-3135 ), MacRitchie Reserve , 01°21'10.2"N, 103°46'33.6"E, 68 m, coll. T. Robillard, 2 Jul.2009 ; 1 juvenile, night (TR13) ( MNHN), Central Catchment Nature Reserve , secondary forest, 1, 01°22'49.0"N, 103°49'06.7"E, 79 m, coll. T. Robillard, 16 Jun.2011 . 6 males, call recording and copulation ( MNHN) ; 7 males ( MNHN) ; 5 females, recording of copulation ( MNHN) ; 2 females ( MNHN), Singapore, reared specimens (generations F1–F6), 2009–2012, coll. T. Robillard ; 1 male, 1 female, grassy to shrubby plot, Neo Tiew Lane 2, Singapore, 17 Jul.2010, coll. M. K. Tan ; 1 male, secondary forest, Hindhede Nature Park , Singapore, 30 Oct.2010, coll. M. K. Tan. Malaysia: 1 male, edge of swamp forest, Mersing , Johor, Malaysia, Jan.1993, coll. D. H. Murphy ( ZRC) ; 3 males, call recording ( MNHN- ENSIF3132-3134 ) , 1 female, open area near track, Petalling Jaya , Mount Kiara, Selangor, Malaysia coll. T. Robillard, 7 Sep.2002 ; 15 males, 12 females, 6 juveniles ( MNHN), reared specimens (generations F1–F4), 2002–2004, coll. T. Robillard .

Diagnosis. — Species of average size, colouration contrasting with black and yellow, characterised by black vertex, yellow face, orange brown legs, MA/MP area yellow in male, black in female, and details of male and female genitalia.

Redescription. — Habitus typical of this genus ( Figs. 1 , 3 ). Vertex black with yellow margin around eyes ( Fig. 4 ). Fastigium black with yellow margins, with few white setae. Scapes yellow to brown, with black patterns. Antennae black with white rings widely spaced out, brown basally. Face yellow, sometimes with a few black spots; facial part of fastigium with 2 black stripes. Mouthparts variable, from brown to yellow. Maxillary palpi yellow; apical segment black apically. Head lateral side yellow, sometimes black behind eyes. Pronotum covered with white setae; disk rectangular to slightly trapezoidal, posterior margin slightly bisinuated; dark grey to black, with tint of yellow. Lateral lobes of pronotum black dorsally, yellow ventrally. Legs orange brown to yellowish brown. Hind femora brown, knees dark brown to black; hind tibiae brown with black spines and spurs, dark brown to black near distal end; tarsomeres dark brown to black. Tarsomeres III with 0–1 spines on dorsoexternal edges (n = 3). Hind wings bicoloured, hyalinous brown apically, basally transparent; longer than FWs, the dark brown tail exceeding the forewings more than twice as long as the pronotum. Tergites light brown mottled with black; sternites pale, with black median area. Cerci light brown, short and conical.

Male. FW colouration ( Fig. 5A ): Dorsal field cells mostly transparent, veins mostly dark brown to black. Basal area velvety black, basally yellow, brown towards distal part. Cell between 2A and 3A at chordal area yellow. CuA, MA and MP black; R yellow, R projections yellow basally, black apically. Lateral field basally yellow, MA/MP yellow, transparent ventrally to R. FW venation ( Fig. 5A ): 1A curved, slightly bisinuated; stridulatory vein with 80–110 teeth on transverse part of 1A only ( Table 1; Fig. 5C ), with a large hook-like tooth near base of 1A ( Fig. 5D ). Harp slightly longer than wide, with 2 harp veins, distal one bifurcate. c1 long and wide, c2 shorter and slightly narrower than c1; mirror (d1) longer than wide, not rounded, generally separated in two parts by a faint transverse vein, the posterior part rectangular, shorter than anterior part. Cell d2 as wide a d1, usually subdivided by accessory veins. Apical field short and rounded, with 3 wide cell alignments posterior to mirror and a narrow apical alignment. Lateral field with 5–7 projections of R (m = 6, n = 4) and 2–3 anterior ventral veins (m = 3, n = 4). Epiproct black. Subgenital plate pale with median area black.

Male genitalia ( Fig. 6 ). Pseudepiphallus sclerotised, anterior and posterior margins slightly indented. Posterior apex with paired lophi longer than wide, sclerotised laterally only and covered with strong short setae; apex of lophi slightly folded dorsally. Rami slightly swollen preapically, their narrow apex convergent. Pseudepiphallic parameres narrow, divergent posteriorly, their basis membranous, with a sclerotised lobe on anterior apex. Ectophallic arc complete and wide. Ectophallic fold narrowed preapically, with strong rounded lateral sclerites; apex narrow and membranous between anterior apex of pseudepiphallic parameres. Ectophallic apodemes long and slightly divergent. Endophallic sclerite large and sclerotised, its posterior apex with divergent lateral arms and with a short median expansion curved dorsally. Endophallic apodeme with lateral lamellas and dorsal crest longer than wide. Membrane of endophallic cavity smooth.

Female. FW colouration ( Fig. 5B ): cells dark grey to black, veins generally yellow brown, sometimes pale yellow to white, more or less distinct. CuA yellow to orange brown. Lateral field: MP orange brown, MA black, R yellow, including its bifurcations; except for veins, areas between veins CuA and R black; ventral part of lateral field transparent. FW venation: 7–10 strong longitudinal veins on dorsal field (m = 8.5, n = 1); lateral field with 4–6 projections of R (m = 5, n = 4) and 2–3 anterior ventral veins (m = 3, n = 4).

Female genitalia. Ovipositor: nearly as long as hind femora; apex thin with both dorsal and ventral edges smooth ( Fig. 7A ). Copulatory papilla conical, apex folded ventrally, pointed and sclerotised; dorsal face with a slecrotised area ( Fig. 7D ).

Juvenile. First instars mostly black. Following instars characterised by black and pale yellow striped colouration. Subadult colouration light brown mottled with dark brown and black, with a black transverse band on abdomen ( Fig. 8C ).

Variation. — Populations from Singapore and Malaysia are very similar but they slightly differ from specimens from south Sumatra (neotypes) by details of colouration and proportions. Specimens from Sumatra tend to be larger (see Table 1), females have longer ovipositor and their venation is usually more distinct, with a yellowish line along lateral edge of dorsal field. Female copulatory papilla tend to be more sclerotised dorsally in specimens from Singapore .

Life history traits. — N. vittatus is a diurnal species living in many lowland secondary habitats, on low plants and bushes on forest edges, along tracks and in clearings. Males sing from leaves of plants from early morning to dusk. Mating

couples are generally observed on plant leaves during the day ( Fig. 8 ).

Behaviour. — Calling song ( Fig. 9 ): In the field (n = 4; t°C = 30–32°C), the calling song of N. vittatus consists in rapid triplets of syllables repeated at length to form a continuous trill. Each syllable has a duration of 6.9 ± 1.4 ms. The spectrum shows a dominant peak at 7.3 ± 0.1 kHz and several peaks harmonically related; the first peak of the spectrum slightly dominates over the other peaks. Mating behaviour: Observations in the field and in the laboratory showed multiple matings as described in another Nisitrus species by Preston-Mafham (2000) (T. Robillard, pers. obs.) ( Fig. 8B ).

Measurements. See Table 1.

Figures

Fig. 1. Habitus of Nisitrus vittatus, drawing by Vanessa Damianthe & Gilbert Hodebert (MNHN). Male specimen from Singapore. Scale bar = 5 mm.

Fig. 2. Metanotal glandular structures in Nisitrus vittatus. A, glandular pits (drawing by G. Hodebert (MNHN) modified from Robillard & Desutter-Grandcolas, 2004a); B, SEM view of glandular pores on scutum; C, SEM view of glandular pores on scutellum. Scale bars = 5 mm (A), 1 μm (B), 10 μm (C).

Fig. 3. Nisitrus vittatus: A, B, male; C, D, female. A, C, dorsal view; B, D, lateral view. Scale bar = 1 cm.

Fig. 4. Nisitrus vittatus, head: A, dorsal view; B, facial view; C, lateral view. Scale bar = 1 mm.

Fig. 5. Nisitrus vittatus: A, FW venation in male; B, FW venation in female; C, SEM view of stridulatory file; D, basal notch. Blue arrow shows approximate location of the basal notch on FW venation. Scale bars = 1 mm (A, B), 100 μm (C, D).

Fig. 6. Nisitrus vittatus, male genitalia: A, dorsal view; B, ventral view. Scale bars = 1 mm.

Fig. 7. Female genitalia: A–C, apex of ovipositor; D–F, copulatory papilla. A, D, Nisitrus vittatus; B, E, Lebinthus bitaeniatus; C, F, Lebinthus luae. Scale bars = 1 mm.

Fig. 8. Nisitrus vittatus: A, female on low vegetation along track in McRitchie reservoir park in Singapore; B, couple mating at night along Wallace Trail, Hindhede Nature Park, Singapore; C, subadult specimen in Wallace Trail, Hindhede Nature Park, Singapore.

Fig. 9. Calling song of Nisitrus vittatus. Oscillogram of 4 echemes (A); oscillogram (B) and sonogram (C) of 1 echeme; linear power spectrum of 1 syllable (D).