Bobilla nigrova ( Swan, 1972 )

Hegg, Danilo, 2024, Small crickets of New Zealand (Orthoptera: Grylloidea: Trigonidiidae and Mogoplistidae), with the description of two new genera and species, European Journal of Taxonomy 955 (1), pp. 1-87 : 24-29

Bobilla nigrova ( Swan, 1972)

Figs 3 , 4A , 9–11 , 15A–F , 16A–B , 38C

Pteronemobius nigrovus Swan, 1972: 534–535 , figs 3–4.

Pteronemobius bivittatus – Hudson 1973: 167–169 (pars).

Pteronemobius nigrovus – McIntyre 1977a: 63–72; 1977b: 319–323; 1978: 3–10.

Pteronemobius (Bobilla) nigrovus – Masaki et al. 1987: 354, fig. 8.

Bobilla nigrova – Otte et al. 1987: 399.

Diagnosis

A medium- to large-sized ground cricket (body length 6 to 9 mm), dark gray to black colour. Males with spike-like tufts of bristles on each side of the suranal plate. Male tegmina with more than 180 teeth in stridulatory file; ratio PCSD /PCLD between 0.438 and 0.488 (mainland New Zealand only, excluding Chatham Islands). Females with long ovipositor (4.0 mm to 6.7 mm), strongly denticulate at apex. Disambiguation from Bobilla bigelowi generally requires microscope examination (see Table 1 ) or sound analysis.

Etymology

From the Latin ‘ nĭgĕr ’ (adj.), ‘black’, and ‘ōva’ (noun, pl.), ‘eggs’. The eggs of Bobilla nigrova are black ( Fig. 10F ). Nigrovus is an adjective. As per Section 34.2 in the ICZN Code, “the ending of a Latin or latinized adjectival or participial species-group name must agree in gender with the generic name with which it is at any time combined” ( ICZN 1999). Since Bobilla is female gender, the adjective nigrovus must take female gender also.

Material examined (see also Supp. file 1: Table S1 )

Holotype

NEW ZEALAND • ♂, adult; Mid Canterbury (MC), Ilam; 43.52318° S, 172.58565° E; 14 m a.s.l.; 21 May 1970; D.I. Swan leg.; in grassland; NZAC 03016349 .

Paratypes

NEW ZEALAND • 25 ♂♂, 41 ♀♀, adults; same data as for holotype; NZAC 03016448 • 1 ♂, adult; same data as for holotype; 28 Aug. 1970; D.I. Swan leg.; in grassland; NZAC 03016361 .

Other material

NEW ZEALAND – Dunedin (DN) • 2 ♂♂, 1 ♀; Signal Hill , Dunedin; 45.86207° S, 170.53995° E; 200 m a.s.l.; 14 Apr. 2024; D. Hegg leg.; grassland; trowel and jar; MPN OR0409 to OR0411 • 2 ♂♂, 2 ♀♀; McGregors Hill , Dunedin; 45.83906° S, 170.56957° E; 270 m a.s.l.; 15 Apr. 2024; D. Hegg leg.; grassland; insect net; MPN OR0412 to OR0415 . – Central Otago (CO) • 5 ♂♂, 3 ♀♀; Clutha Gold Trail ; 45.85559° S, 169.59715° E; 160 m a.s.l.; 31 Jan. 2024; D. Hegg leg.; grassland; insect net; MPN OR0125 to OR0132 • 1 ♂; Big Hut track, Rock and Pillar Range; 45.44488° S, 170.09697° E; 750 m a.s.l.; 1 Jul. 2021; D. Hegg leg.; mixed grass and snow; insect net; MPN OR0478 • 2 ♀♀; Earnscleugh Tailings , Alexandra; 45.24063° S, 169.36048° E; 140 m a.s.l.; 18 Mar. 2021; D. Hegg leg.; dirt track; insect net; MPN OR0043 , OR0044 . – Mackenzie (MK) • 1 ♀; Lake Ōhau ; 44.26171° S, 169.81649° E; 600 m a.s.l.; 1 May 2022; D. Hegg leg.; grassland; insect net; MPN OR110 • 1 ♂, 3 ♀♀; Lake Ōhau ; 44.25812° S, 169.81463° E; 620 m a.s.l.; 24–26 Feb. 2023; D. Hegg leg.; grassland; insect net; MPN OR0108 , OR0109 , OR0111 , OR0112 • 1 ♂; Tekapo ; 44.00842° S, 170.49794° E; 720 m a.s.l.; 4 Apr. 2021; D. Hegg leg.; in short grass; jar; MPN OR0045 • 1 ♂; Patersons Terrace , Tekapo; 44.05623° S, 170.42581° E; 700 m a.s.l.; 17 Feb. 2022; D. Hegg leg.; on 4WD track; insect net; MPN OR0134 . – South Canterbury (SC) • 1 ♂, 4 ♀♀; Fairlie ; 44.09342° S, 170.82757° E; 300 m a.s.l.; 4 Apr. 2021; D. Hegg leg.; in short grass in picnic area; jar; MPN OR0451 to OR0455 . – Mid Canterbury (MC) • 1 ♀; Glenrock Stream , Rakaia River; 43.33354° S, 171.37505° E; 630 m a.s.l.; 28 Jul. 2023; D. Hegg leg.; grassy 4WD track; jar; MPN OR0136 . – Buller (BR) • 1 ♀; Boyle River ; 42.55859° S, 172.35076° E; 520 m a.s.l.; 3 Apr. 2021; D. Hegg leg.; short grass on road verge; insect net; MPN OR0046 . – Kaikōura (KA) • 1 ♀; Kahutara River ; 42.37725° S, 173.44202° E; 270 m a.s.l.; 12 Mar. 2023; D. Hegg leg.; on gravel road; insect net; MPN OR0133 . – Wanganui (WI) • 1 ♂; McPhersons Bush ; 39.94103° S, 175.33579° E; 150 m a.s.l.; 17 Mar. 2023; D. Hegg leg.; tall grass on road verge; insect net; MPN OR0147 . – Rangitikei (RI) • 1 ♂, 1 ♀; Waipawa Forks Hut ; 39.79859° S, 176.17517° E; 720 m a.s.l.; 14 Mar. 2024; D. Hegg leg.; in lawn outside hut; insect net; MPN OR0310 , OR0311 . – Rangitikei / Taupō (RI /TO) • 2 ♀♀; Ohakune ; 39.42592° S, 175.44136° E; 650 m a.s.l.; 13 May 2023; D. Hegg leg.; in road pull-out; jar; MPN OR0121 , OR0122 . – Waikato (WO) • 2 ♂♂, 2 ♀♀; Manganui Road , Awakino; 38.61659° S, 174.67720° E; 50 m a.s.l.; 29–30 Mar. 2022; D. Hegg leg.; tall grass on road verge; trowel and jar; MPN OR0113 to OR0116 . – Bay of Plenty (BP) • 1 ♂; Hurunui Hut , Kaimai Range; 37.81700° S, 175.92802° E; 540 m a.s.l.; 15 Apr. 2023; D. Hegg leg.; in grass; insect net; MPN OR0124 • 2 ♂♂, 3 ♀♀; Little Manganuku Saddle ; 38.27295° S, 177.38828° E; 550 m a.s.l.; 18 Apr. 2021; D. Hegg leg.; on walking track; insect net; MPN OR0443 to OR0447 . – Gisborne (GB) • 1 ♀; Hikurangi ; 37.90100° S, 178.06144° E; 1020 m a.s.l.; 19 Apr. 2024; D. Hegg leg.; on 4WD track; jar; MPN OR0416 . – Bay of Plenty / Coromandel (BP/CL) • 1 ♂; Waihi ; 37.38992° S, 175.83290° E; 100 m a.s.l.; 25 Mar. 2024; D. Hegg leg.; in lawn; jar; MPN OR0343 . – Coromandel (CL) • 1 ♀; Coromandel ; 36.76217° S, 175.49142° E; 10 m a.s.l.; 13 Apr. 2021; D. Hegg leg.; short grass in picnic area; jar; MPN OR0481 • 1 ♂; same data as for preceding; 6 Apr. 2024; MPN OR0398 . – Auckland (AK) • 1 ♀; Avondale Motor Park , Auckland; 36.89795° S, 174.70778° E; 40 m a.s.l.; 28 Mar. 2022; D. Hegg leg.; on sparsely vegetated ground; jar; MPN OR0123 • 2 ♂♂, 1 ♀; Kaipara Harbour ; 36.48248° S, 174.45069° E; 20 m a.s.l.; 2 May 2021; short grass on road verge; jar; MPN OR0475 to OR0477 . – Northland (ND) • 1 ♀; Kerikeri ; 35.24029° S, 173.93822° E; 100 m a.s.l.; 23 Mar. 2022; D. Hegg leg.; in tall grass; insect net; MPN OR0135 • 1 ♂, 1 ♀; Maitai Bay , Karikari Peninsula; 34.82342° S, 173.40619° E; 30 m a.s.l.; 28 Mar. 2024; D. Hegg leg.; in grass; trowel and jar; MPN OR0357 , OR0358 . – Chatham Islands (CH) • 1 ♂; Canister Cove , Pitt Island; 44.33332° S, 176.22676° W; 50 m a.s.l.; 15 Feb. 2024; D. Hegg leg.; short ground cover; jar; MPN OR0137 • 7 ♂♂, 2 ♀♀; Pitt Island ; 44.3235° S, 176.2337° W; 120 m a.s.l.; 16 Feb. 2024; D. Hegg and S. Purdie leg.; pasture grass; jar; MPN OR0138 to OR0146 .

Description

Refer to the detailed description in Swan (1972). See also Fig. 10 in this work.

MEASUREMENTS. See Tables 1 and 2 . Females are larger than males.

SONG. Bobilla nigrova sings at a frequency of 8 kHz at 27°C, with a pulse rate of 10 to 15 pulses per second. Refer to the detailed description in McIntyre 1977a. See also Fig. 11 and Table 2 in this work. The low pulse rate (<15 pulses / s) is the main feature that distinguishes the song of B. nigrova from the song of B. bigelowi .

Habitat and ecology

Common and widespread in meadows and grasslands throughout New Zealand, including sports fields and urban parks, Bobilla nigrova is mainly active during the day; it may sing through the night on warm nights only. Bobilla nigrova is a seasonal species; adults are most frequently encountered in late summer and autumn. Bobilla nigrova forms mixed populations with B. bigelowi and with species in the genus Pteronemobius , with which it can easily be confused.

Distribution

All of New Zealand, including Chatham Islands, but excluding Rakiura/ Stewart Island and subantarctic islands ( Fig. 38C ).

Figures

Fig. 3. Morphometric measurements for the New Zealand species of Bobilla Otte & Alexander, 1983. In all graphs, white shapes indicate B. bigelowi (Swan, 1972), dark shapes indicate B. nigrova (Swan, 1972). Both sexes are included unless stated otherwise. A. Boxplot of the ratio of the short and long diagonals in the right male forewing’s posterior cell of the harp (see Fig. 1B). The whiskers include the minimum and maximum values. B. Stridulatory file in male cricket’s right forewing. C. Intraocular distance vs eye length (Fig. 1C). D. Body length vs ovipositor length (Fig. 1D). E. Major vs minor axis of tympanum (Fig. 1E). For each cricket, the measurements of both left and right tympana are included. F. Length of middle vs dorsal inner apical spurs on tibia III (Fig. 1A).

Fig. 4. Inner spurs at apex of tibia III in Bobilla nigrova (Swan, 1972) and in B. bigelowi (Swan, 1972). Apical spurs tai2 and tai3 are generally subequal in length in B. nigrova, whereas tai2 is shorter in B. bigelowi (see Fig. 3F). Scale bars = 500 µm.

Fig. 9. Bobilla nigrova (Swan, 1972). A–B. Lake Ōhau, Mackenzie Country. A. Dorsal view of adult ♂ (MPN OR0108). B. Dorsal view of adult ♀ (MPN OR0109). C. Earnscleugh Tailings, Alexandra. Lateral view of adult ♀ (MPN OR0044). Scale bars = 2 mm.

Fig. 10. Bobilla nigrova (Swan, 1972). A. Lateral view of head, adult ♀. B. Frontal view of head, adult ♀. C. Dorsal view of right forewing in adult ♂. D. Dorsal view of male terminalia showing conspicuous hair tuffs. E. Right hindwing in adult female, dorsal view. F. Egg. G–H. Apex of ovipositor, dorsal view showing strong denticulation on lateral valves. I. Ovipositor, lateral view. All images Lake Ōhau, Mackenzie Country (♂ MPN OR0108; ♀ MPN OR0109), except for D (MPN OR0446) and G (MPN OR0443) from Little Manganuku Saddle, Bay of Plenty, and E (MPN OR0131) from Clutha Gold Trail, Otago. Scale bars = 500 μm.

Fig. 11. Bobilla nigrova (Swan, 1972) song, recorded in captivity at 21°C. Specimen collected at Lake Ōhau, Mackenzie Country. A. Spectrogram of a sequence of three chirps. B. Oscillogram of a sequence of three chirps. C. Oscillogram of one chirp consisting of six pulses. D. Power spectrum of a sequence of three chirps.

Fig. 15. Bobilla Otte & Alexander, 1983, ♂ genitalia of New Zealand species. A–F. Bobilla nigrova (Swan, 1972). A–C. Microscope images of pseudepiphallic sclerite. Coromandel (MPN OR0481). A. Dorsal view. B. Ventral view.C. Lateral view.D–F. Micro CT scans. Ruahine Forest (MPN OR0310). D. Dorsal view, Maximum Intensity Projection (MIP). E. Cross-section, dorsal view, Volume Blending. F. Lateral view, MIP. G–L. Bobilla bigelowi (Swan, 1972). Ruahine Forest. G–H. Microscope images of pseudepiphallic sclerite (MPN OR0313). G. Dorsal view. H. Ventral view. I–L. Micro CT scans, MIP (MPN OR0312). I. Posterior-lateral view (45º angle). J. Ventral view. K. Cross-section, dorsal view. L. Lateral view. Scale bars = 250 μm.

Fig. 16. Live Bobilla Otte & Alexander, 1983. A–B. Bobilla nigrova (Swan, 1972). A. Adult ♂, Hurunui Hut, Kaimai Range. B. Adult ♀. Earnscleugh Tailings, Alexandra, Central Otago. C–F. Bobilla bigelowi (Swan, 1972). C. Adult ♂, Poulter River, Arthur’s Pass National Park. D. Fully winged adult ♂, Lake Ōhau. E. Adult ♀ with short forewings. Kaikōura. F. Adult ♀ with long forewings. Leitchs Clearing, Herangi Range. Note: only B is photographed in its natural environment. All other specimens are posed on unnatural backgrounds in captivity.

Fig. 38. Map of New Zealand, showing the known distribution of taxa included in this study. Thin black lines indicate the boundaries of Crosby’s entomological regions (Crosby et al. 1998; Fig. 2). Coloured circles indicate the collection localities for the material examined.