Lebinthus santoensis, Robillard, 2009

Robillard, Tony, 2009, Eneopterinae crickets (Insecta, Orthoptera, Grylloidea) from Vanuatu, Zoosystema 31 (3), pp. 577-618 : 600-605

Lebinthus santoensis n. sp.

( Figs 1E, F ; 3B ; 6G ; 9 ; 10 A-C; 11A; 12A-C; 16; 18)

Lebinthus sp. – Robillard et al. 2007: 1254 (calling song analysis).

TYPE MATERIAL. — Vanuatu. [Province Sanma], Espiritu Santo Is., Peavot, végétation arbustive en arrière de la plage, 14°59’09’’S, 166°47’39’’E, 21.X.2006, jour (nº 16), L. Desutter-Grandcolas, ♂ holotype ( MNHN- ENSIF2434). — Same locality, date and collector and as holotype, jour (nº 23), litière, ♀ allotype ( MNHN- ENSIF2435).

Paratypes (39 ♂♂, 37 ♀♀): Vanuatu. [Province Sanma], Espiritu Santo Is., Matantas , pointe de Quirros , 15°09’54’’S, 166°56’22’’E, 20 m en haut de la plage, litière et herbes basses, 19.X.2006, jour, 6AM, 1 ♂ (TR-186), enregistrement en semi-captivité TR-take 49, 1 ♂ (TR-183), photo SH, 6 ♂♂ (TR-187-191), 2 ♂♂ (TR-194, 201, alcool), 6 ♀♀ (TR-183, 196-199, 202), T. Robillard (MNHN-ENSIF2436-2451). — Matantas, Big Bay, Vatthé Conservation area, 15°20’S, 166°95’E, végétation arbustive et basse en zone supralittorale, 25.X.2006, jour, 1 ♂ (TR-344), litière de feuilles mortes ; 27.X.2006, jour, 1 ♂ (TR-371), 4 ♀♀ (TR-374, 375, 378, 379), T. Robillard (MNHN-ENSIF2452-2457); 27.X.2006, jour, 3 ♂♂ (nº 16-18), 7 ♀♀ (nº 19-25), litière, L. Desutter-Grandcolas (MNHN-ENSIF2458- 2467); 27.X.2006, jour, 1 ♂ (nº 15), litière, L. Desutter- Grandcolas ( BMNH). — Matantas, Big Bay , Vatthé Conservation area, 15°20’S, 166°95’E, haut de plage, 27.X.2006, jour, 1 ♂ (TR-382), photo TR site d’étude ; 27.X.2006, nuit, 2 ♂♂, galets et zone médiolittorale émergée, litière, T. Robillard (MNHN-ENSIF2468- 2470). — Peavot, rive S de la rivière principale, terrasse I, 14°59’37’’S, 166°47’04’’E, 38 m alt., forêt secondaire (ancien jardin), litière, 20.X.2006, jour 9AM-3PM, 3 ♂♂ (TR-237, 240, 243), 3 ♀♀ (TR-236, 242, 244); 21.X.2006, nuit, 1 ♀ (TR-280), 1 ♂ (TR-278), T. Robillard (MNHN-ENSIF2471-2475, 2477, 2478, 2492); 20.X.2006, jour, 1 ♀ (nº 54), photo SH, L. Desutter- Grandcolas (MNHN-ENSIF2479). — Peavot, végétation arbustive en arrière de la plage, 14°59’09’’S, 166°47’39’’E, 21.X.2006, jour, 1 ♀ (TR-258), plage de galets et zone médiolittorale émergée, litière, 24.X.2006, jour, 2 ♀♀ (TR-312, 313), litière; 24.X.2006, nuit, 1 ♂ (TR-323), plage de galets et zone médiolittorale émergée, 200 m au sud du village, litière dans une feuille morte, enregistrement TR-takes 70-71, T. Robillard (MNHN-ENSIF2480- 2483); 21.X.2006, jour, 1 ♀ (nº 19), litière, PIII: molec TR; 6 ♂♂ (nº 11-15, 17), 4 ♀♀ (nº 18, 20-22), litière; 24.X.2006, nuit, 1 ♂ (nº 14), L. Desutter-Grandcolas (MNHN-ENSIF2484-2490, 2493-2497). — Nattawa, forêt pâturée, 15°19’29’’S, 167°12’09’’E, 29.X.2006, jour, 1 ♀ (TR-421), litière en lisière, souche d’élevageTR-Santo, T. Robillard (MNHN-ENSIF2498); 29.X.2006, jour, 2 ♂♂ (nº 1, 2), 2 ♀♀ (nº 3, 4), litière et herbes basses en clairière, L. Desutter-Grandcolas (MNHN-ENSIF2499- 2502). — Luganville, site du CTRAV, forêt côtière sur sable, 15°27’00’’S, 167°12’26’’E, 29.X.2006, nuit, 1 ♂ (TR-446), litière, feuilles mortes, enregistrement en milieu naturel (chant d’appel) TR-takes 75-77, 2 ♀♀ (TR-447-448), 1 ♀ (TR-449), litière; 30.X.2006, nuit, 1 ♂ (TR-472), litière, enregistrement en milieu naturel (chant d’appel) TR-takes 79-81, 1 ♂ (TR-473), litière, vidéo SH, 2 ♂♂ (TR-475), 1 ♀ (TR-474), litière, PIII: molec TR; 31.X.2006, nuit, 1 ♂ (TR-481), litière, enregistrement en milieu naturel (chant d’appel) TR-take 88, T. Robillard (MNHN-ENSIF2503-2512).

TYPE LOCALITY. — Vanuatu, Espiritu Santo Is., Peavot, végétation arbustive en arrière de la plage, 14°59’09’’S, 166°47’39’’E.

ETYMOLOGY. — Species named after Espiritu Santo Is., Vanuatu.

OTHER MATERIAL EXAMINED. — (6 ♀♀, 7 ♂♂, 37 juv.) Vanuatu. [Province Sanma], Espiritu Santo Is., Matantas, pointe de Quirros, 15°09’54’’S, 166°56’22’’E, 20 m en haut de la plage, litière et herbes basses, 19.X.2006, jour 6AM, 1 ♀ juv. (TR-202), T. Robillard ( MNHN- ENSIF2513 ). — Matantas, Big Bay, Vatthé Conservation area , 15°20’S, 166°95’E, végétation arbustive et basse en zone supralittorale, 27.X.2006, jour, 1 ♀ juv. (TR-370), 4 juv. (TR-372, 373, 376, 377), litière, photo site TR, T. Robillard (MNHN-ENSIF2514-2518) ; 26.X.2006, jour, 1 juv. (nº 1), litière, L. Desutter-Grandcolas ( MNHN- ENSIF2519 ). — Peavot, rive S de la rivière principale, terrasse I, 14°59’37’’S, 166°47’04’’E, 38 m alt., forêt secondaire (ancien jardin), 20.X.2006, jour 9AM-3PM, 2 juv. (TR-234, 235) ; 21.X.2006, nuit, 2 ♀♀ juv.(TR-277, 279), litière, T. Robillard (MNHN-ENSIF2476, 2520- 2522); 20.X.2006, jour, 2 ♀♀ juv. (nº 43, 44), 8 juv. (nº 34, 35, 38-41, 45, 47), litière, 1 juv. (nº 63), pelouse/zone herbacée en clairière; 21.X.2006, jour, 3 juv. (nº 6-8), litière, L. Desutter-Grandcolas (MNHN-ENSIF2523- 2536). — Peavot, végétation arbustive en arrière de la plage, 14°59’09’’S, 166°47’39’’E, 21.X.2006, jour, 3 juv. (TR-256-258), litière; 24.X.2006, jour, 1 ♀ juv. (TR-311); 24.X.2006, nuit, plage de galets et zone médiolittorale émergée, 200 m au sud du village, 1 juv. (TR-320), T. Robillard (MNHN-ENSIF2537-2541); 21.X.2006, jour, 4 juv. (nº 25-28), litière, 1 ♀ juv. (nº 24), litière; 24.X.2006, nuit, 1 ♀ juv. (nº 15), litière, L. Desutter-Grandcolas (MNHN-ENSIF2491, 2542-2546). — Penaoru, 600 m, XI.2006, 3 juv. (ortho 2) [alcool], molec. TR, Exped. SANTO 2006 (MNHN-ENSIF2547). — [Vanuatu] Nouvelles-Hébrides, [Province Penama], [Pentecost] Pentecôte Is. , Baie Melsisi , 1935-1936, 1 ♀, E. Aubert de la Rüe (MNHN-ENSIF1170). — Reared specimens from Espiritu Santo Is. : F1, 2006-2007, 5 ♂♂ (4 recorded, MNHN-ENSIF2550-2553), 3 ♀♀, 1 juv. ♀ [alcool] ; F2, 2007-2008, 2 ♂♂ (recorded, MNHN-ENSIF2554, 2555), 2 ♀♀, 1 juv., T. Robillard ( MNHN) .

DISTRIBUTION. — Vanuatu, Espiritu Santo Is. and Pentecost Is., coastal areas.

DIAGNOSIS. — Species of small size, close in shape, colouration, venation and genitalia to Lebinthus lifouensis Desutter-Grandcolas, 1997 , from which it differs by details of colouration (dark apical ring on cerci), female copulatory papilla (basal sclerotized ring smaller), ovipositor (slightly more acute [ Fig. 6G ]), and by a calling song frequency of about 26.6 kHz (12.6 in L. santoensis: Robillard et al. 2007 ).

DESCRIPTION

Species of small size. Colouration ( Figs 9 ; 18E, F ) most often light brown dorsally and darker ventrally, with more or less contrasted colour patterns. Head dorsum light brown with 6 more or less visible longitudinal bands, 2 median ones, patchy at level of fastigium, next 2 lateral ones curved externally toward eyes midlength, 2 most external ones behind eyes. Some specimens with almost completely light brown or dark brown head dorsum with faint banded patterns. Eyes light brown dorsally, dark brown to black ventrally. Fastigium slightly wider than long, setose, whitish brown with a dark spot behind whitish median ocellus. Scapes whitish, antennae homogeneously brown. Face with 2 diverging black curved lines between antennae, with a median black triangle above clypeus; black areas bellow antennae; these elements more or less separated or fused according to specimen general melanisation. Mouth parts dark brown to black. Palpi whitish, banded with dark brown. Pronotum: Dorsal disk almost rectangular, straight posteriorly; light brown, whitish laterally, most often with dark spots arranged in uneven lines. Lateral lobes black except for whitish ventral margin, sometimes partly brown. Legs: fore and mid femora with large dark brown to black spots, fore and mid tibiae banded; fore tibia not widened at tympana level.Hind femur brown, with striated light patterns on external face, 3-5 black spots on each ventral edge, knees dark brown; distal half of hind tibiae and tarsomeres III-1 black. Hind tibiae dorsal faces with 5-9 inner (m = 6, n = 10) and 8-13 outer (m = 10, n = 10) spines above spurs, and 3-5 inner (m = 4, n = 10) and 2-5 outer (m = 5, n = 10) spines between spurs. Tarsomeres III-1 with 4 spines on dorso-external edges (n = 10). Hind wings absent, FWs short. Abdomen brown, with a black or dark brown band on each lateral side; each tergite with dark spots on posterior margin. Cerci homogeneously brown, dark brown at base ventrally, with a preapical black ring, unlike L. lifouensis .

Male

FW not reaching abdomen midlength ( Fig. 9 ). FW colouration ( Fig. 1E, F ): cells brown, veins whitish, translucent; area between CuA and MP dark brown; intermedian area whitish; lateral field dark brown, its ventral margin lighter. FW venation: 1A angle wide (>130°); stridulatory file with 150-193 teeth (m = 172, n = 4), located on both transverse (121- 135 teeth, m = 128) and basal longitudinal (29-66 teeth, m = 44) parts of 1A ( Fig. 3B ). CuP missing. Harp wide, with generally one harp vein parallel to transverse axis, but some specimens with 2 parallel harp veins. CuA curved internally at apex, the median fold triangular and short, located on dorsum. Cell c1 separated at midlength by an accessory vein, c2 large. Mirror (d1) not rounded, barely widened compared to other cell alignments; d2 thin and rectangular. Apical field almost absent, including only 2 cells behind mirror (E alignment). Lateral field with 5 strong longitudinal veins including MA, R and 3 more ventral veins; latero-dorsal angle made by MP; R without strong bifurcating veins.

Male genitalia ( Fig. 10 A-C): very similar to L. lifouensis , but pseudepiphallic lophi more acute. Pseudepiphallic sclerite triangular, slightly convex dorsally; anterior apex straight or slightly indented; posterior apex with individualized lophi, setose. Pseudepiphallic parameres large, trilobate and close together. Ectophallic arc complete and wide, at midlength between pseudepiphallic parameres and anterior apex. Ectophallic fold short and wide, with a Y preapical sclerotization. Endophallic sclerite Yshaped; endophallic apodeme made of a long and wide median crest, not disconnected from membrane.

Female

FWs short ( Fig.11A ), exceeding posterior margin of first tergite, separated by a distance equal to length; dorsal field with 4 or 5 strong longitudinal veins, whitish or brown. Lateral field darker than dorsal field, with 3 or 4 strong dark brown longitudinal veins. Ovipositor short; apex lanceolate, denticulate on dorsal edge.

Female genitalia: copulatory papilla ( Fig. 12 A-C) with small basal sclerotized ring; apex narrowed and long, with a ventral bump.

Juvenile

Colouration generally more contrasted than adults, with a pair of dark brown patterns on first tergites ( Fig. 18F ).

Measurements

See Table 11.

HABITAT AND LIFE HISTORY TRAITS

Lebinthus santoensis n. sp. lives in leaf litter in open forested areas in coastal areas, near river banks or along beaches ( Fig. 18A, B ). It is found in dense populations in wet leaf litter, generally on or under large dead leaves ( Tables 1, 2; Fig. 18C, D ).

BEHAVIOUR

Mating behaviour has been observed in laboratory (TR, 2006-2008); multiple copulations have been recorded (2-6 copulations, n = 2); between each copulation (c. 45- 60 min) the male actively guards the passive female by singing almost constantly starting a few minutes after removal of previous spermatophore by the female.

Calling song ( Fig. 16 ; Table 12)

Males start singing during the afternoon from within the leaf litter, but are fully active at night, mostly on top of leaf litter. Five males recorded in the field (MNHN-ENSIF2483, 2503, 2507) and in laboratory (MNHN-ENSIF2551, 2553) at 23-29°C are analysed here. At 25°C, the calling song consists of a continuous succession of two-part echemes separated by a short silence of 1.1 ± 0.4 s (mean echeme duration = 26.2 ± 9.7 s; period = 27.3 ± 10.1 s): each echeme starts by a slow trill, made of 42 ± 9.7 widely spaced syllables, followed by a fast trill (mean trill duration = 11.9 ± 0.6 s; period = 26.7 ± 3.0 s; fast trill/slow trill duty cycle = 45.3 ± 17.7%; fast trill rate = 2.24/min) made of 463.9 ± 27.3 syllables. All syllables are amplitude modulated; syllables of slow trill have the following characteristics: syllable rate = 3.2 ± 0.9/s; syllable duration = 10.8 ± 1.3 ms; syllable period = 322.4 ± 92 ms; syllable duty cycle = 3.3%; whereas syllables of fast trill have the following characteristics: syllable rate = 39.9 ± 1.0/s; syllable duration = 10.9 ± 1.7 ms; syllable period = 25.8 ± 8.3 ms; syllable duty cycle = 42.2%.

The dominant frequency at 25°C is 26.6 ± 1.7 kHz and corresponds to the second harmonic of the song (Robillard et al. 2007); mean fundamental frequency is about twice lower (13.3 ± 0.8 kHz). The dominant frequency of L. santoensis n. sp. is the highest known so far for crickets (Robillard et al. 2007), and this feature constitutes the clearest criteria to distinguish this species from L. lifouensis , for which spectral pattern is similar, but with twice lower frequency values (dominant frequency = 12.6 kHz; fundamental frequency = 6.3 kHz) (Robillard et al. 2007).

Courting song

This song is less intense than the calling song but similar in temporal pattern.

Intercopulatory song

This song is similar to the calling song but less intense; the slow part of the song is more intense than the echeme, and the syllables are more indented than in the calling song. Th is song is almost continuous and starts a few minutes after removal of previous spermatophore by the female.

Aggressive song

This song was not observed despite many observations of male interactions. It is probably absent from the repertoire of this species.

Figures

FIG. 1. — Male FW venation in dorsal and lateral views:A, B, Cardiodactylus enkraussi Otte,2007;C, D, C. tankara n. sp.; E, F, Lebinthus santoensis n. sp.; G, H, L. nattawa n. sp. Abbreviations: see Material and methods. Scale bars: 1 mm.

FIG. 3. — SEM view of stridulatory file: A, Cardiodactylus tankara n. sp.; B, Lebinthus santoensis n. sp.; C, C. enkraussi Otte, 2007; D, L. nattawa n. sp. Photos: S. Hugel. Scale bars: 100 μm.

FIG. 6. — Apex of ovipositor in lateral view: A, Cardiodactylus enkraussi Otte, 2007; B, C. tankara n. sp.; C, C. pentecotensis n. sp.; D, C. aobaensis n. sp.; E, C. cheesmani Otte, 2007a; F, C. epiensis n. sp.; G, Lebinthus santoensis n. sp.; H, L. nattawa n. sp.; I, L. malekulensis n. sp. Scale bar: 1 mm.

FIG. 9. — Lebinthus santoensis n. sp., male habitus, paratype. Scale bar: 5 mm.

FIG. 10. — Male genitalia: A-C, Lebinthus santoensis n. sp., in dorsal (A), ventral (B) and lateral (C) views; D-F, L. nattawa n. sp., in dorsal (D), ventral (E) and lateral (F) views. Abbreviations: see Material and methods. Scale bar: 1 mm.

FIG. 18. — Lebinthus santoensis n. sp.: A, C, E, in Matantas, pointe de Quirros, Espiritu Santo, Vanuatu, by day; A, habitat; C, habitat close up;E, male;B, D, in Big Bay,Vatthé,Espiritu Santo,Vanuatu,by day,along beach;B, habitat;D, habitat close up with juveniles and adults in leaf litter; F, female juvenile,in Peavot, Espiritu Santo, Vanuatu, by day.Photos: S. Hugel (A, C, E, SH-19X06a; F, SH-20x06a) and T. Robillard (B, TR35; D, TR65).

FIG. 11. — Female FW venation: A, Lebinthus santoensis n. sp.; B, L.nattawa n. sp.;C, L.malekulensis n.sp. Dotted areas represent patterns of white or yellow areas.Abbreviations:see Material and methods. Scale bar: 5 mm.

FIG. 12. — Female copulatory papilla in ventral, dorsal and lateral views: A-C, Lebinthus santoensis n. sp.; D-F, L. nattawa n. sp.; G-I, L. malekulensis n. sp. Scale bar: 0.5 mm.

FIG. 16. — Calling song of Lebinthus santoensis n. sp.: A, oscillogram showing two successive echemes; B, detailed sonogram (top) and oscillogram (bottom) of two syllables within the slow part; C, E, detailed sonogram (top) and oscillogram (bottom) of 17 (C) and three (E) syllables within the fast part; D, spectrogram (linear amplitude). Abbreviations: f1-f3, first (fundamental) to third harmonic frequencies; Fd, dominant frequency.