Bobilla bigelowi ( 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 : 29-35

Bobilla bigelowi ( Swan, 1972)

Figs 3 , 4B , 12–14 , 15G–L , 16C–F , 38B

Pteronemobius bigelowi Swan, 1972: 533–534 , figs 1–2.

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

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

Bobilla bigelowi – Otte et al. 1987: 399.

Diagnosis

A medium- to large-sized ground cricket (body length 6 to 9 mm), coloured dark grey or black. Males without spike-like tufts of bristles on each side of the suranal plate. Male tegmina with less than 180 teeth in stridulatory file; ratio PCSD/ PCLD between 0.496 and 0.558. Females with short ovipositor (3.1 mm to 4.9 mm), weakly denticulate at apex. Disambiguation from Bobilla nigrova generally requires microscope examination (See Table 1 ) or sound analysis.

Etymology

Named for Robert Sidney Bigelow, New Zealand entomologist (1918–2000).

Material examined (see also Supp. file 1: Table S2 )

Holotype

NEW ZEALAND • ♂, adult; Kaikōura (KA), Conway Flat, Parnassus; 42.61893° S, 173.45750° E; 10 m a.s.l.; 12 May 1970; D.I. Swan leg.; grassland; NZAC 03015213 .

Paratypes

NEW ZEALAND • 5 ♂♂, 4 ♀♀, adult; same data as for holotype; NZAC 03015516 • 6 ♂♂; Nelson (NN), Richmond ; 41.333° S, 173.183° E; 10 m a.s.l.; 15 May 1970; A. Edgar leg.; grassland (sports field); NZAC 03015522 • 2 ♂♂, 3 ♀♀; Mid Canterbury (MC), Ilam ; 43.52318° S, 172.58565° E; 14 m a.s.l.; 29 August 1970; D.I. Swan leg.; grassland; NZAC 03015677 .

Other material

NEW ZEALAND – Dunedin (DN) • 2 ♀♀; 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 OR0406 , OR0407 . – Central Otago (CO) • 5 ♂♂, 4 ♀♀; 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 OR0456 to OR0464 . – Mackenzie (MK) • 2 ♂♂; Lake Ōhau ; 44.25812° S, 169.81463° E; 620 m a.s.l.; 24 Feb. 2023; D. Hegg leg.; grassland; insect net; MPN OR0436 , OR0437 . – South Canterbury (SC) • 1 ♂; Little Mt Peel ; 43.8811° S, 171.2321° E; 930 m a.s.l.; 27 May 2023; D. Hegg leg.; on walking track; jar; MPN OR0162 . – Mid Canterbury (MC) • 1 ♀; Māhoe Reserve, Lincoln ; 43.63296° S, 172.48729° E; 20 m a.s.l.; 25 Oct. 2021; D. Hegg leg.; grassland; insect net; MPN OR0182 • 5 ♂♂, 2 ♀♀; Tumbledown Bay, Banks Peninsula ; 43.85050° S, 172.77288° E; 10 m a.s.l.; 12 Aug. 2023; D. Hegg leg.; on 4WD track; insect net; MPNOR0174 to OR0180 • 1 ♂, 1 ♀; Mt Hutt Ski-field Road ; 43.54992° S, 171.56014° E; 600 m a.s.l.; 21 Jan. 2024; D. Hegg leg.; roadside vegetation; insect net; MPN OR0183 , OR0184 • 1 ♂, 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 OR0168 , OR0169 • 2 ♂♂, 2 ♀♀; Turtons Saddle, Rakaia River ; 43.35823° S, 171.36818° E; 1100 m a.s.l.; 30 Jul. 2023; D. Hegg leg.; on 4WD track; jar; MPN OR0164 to OR0167 . – North Canterbury (NC) • 2 ♂♂, 2 ♀♀; Poulter River ; 42.97195° S, 171.88941° E; 550 m a.s.l.; 2 Oct. 2021; D. Hegg leg.; on 4WD track; insect net; MPN OR0170 to OR0173 . – Buller (BR) • 1 ♂; Haupiri River ; 42.65391° S, 171.77393° E; 300 m a.s.l.; 23 Oct. 2023; D. Hegg leg.; grassland; jar; MPN OR0187 . – Kaikōura (KA) • 1 ♀; Mt Fyffe car park, Kaikōura ; 42.35158° S, 173.56781° E; 180 m a.s.l.; 5 Jul. 2021; D. Hegg leg.; roadside vegetation; insect net; MPN OR0480 . – Marlborough (MB) • 1 ♀; Jacks Pass ; 42.47697° S, 172.82517° E; 850 m a.s.l.; 12 Apr. 2022; D. Hegg leg.; roadside vegetation; insect net; MPN OR0185 • 1 ♀; Onamalutu Road, Wairau River ; 41.47056° S, 173.73139° E; 80 m a.s.l.; 7 Mar. 2022; D. Hegg leg.; in roadside ditch; jar; MPN OR0181 . – Rangitikei (RI) • 4 ♂♂, 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 OR0312 to OR0316 . – Taranaki (TK) • 1 ♂; Awakino Gorge ; 38.62087° S, 174.74416° E; 130 m a.s.l.; 19 Mar. 2024; D. Hegg leg.; in lawn; jar; MPN OR0317 . – Waikato (WO) • 7 ♂♂, 7 ♀♀; Leitchs Clearing, Herangi Range ; 38.43453° S, 174.76800° E; 270 m a.s.l.; 2 Apr. 2022; D. Hegg leg.; in tall grass; trowel and jar; MPN OR0148 to OR0161 . – 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 OR0163 • 3 ♂♂, 5 ♀♀; Little Manganuku Stream ; 38.26649° S, 177.38991° E; 360 m a.s.l.; 18 Apr. 2021; D. Hegg leg.; stony river bed; insect net; MPN OR0465 to OR0472 . – Gisborne (GB) • 1 ♂; Hikurangi ; 37.86112° S, 178.08154° E; 390 m a.s.l.; 17 Apr. 2024; D. Hegg leg.; on 4WD track; jar; MPN OR0417 . – Northland (ND) • 1 ♀; Kohuroanaki Loop Track , Te Paki; 34.50864° S, 172.82443° E; 90 m a.s.l.; 26 Mar. 2022; D. Hegg leg.; on 4WD track; insect net; MPN OR0186 .

Description

Refer to the detailed description in Swan (1972). See also Fig. 13 in this work.

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

SONG. Bobilla bigelowi sings at a frequency of 7.5 k to 8 Hz at 27°C, with a pulse rate greater than 20 pulses per second. Refer to the detailed description in McIntyre 1977a. See also Fig. 14 and Table 2 in this work. The high pulse rate (> 20 pulses / s) is the main feature that distinguishes the song of B. bigelowi from the song of B. nigrova .

Habitat and ecology

Common and widespread in meadows and grasslands throughout New Zealand, including sports fields and urban parks, Bobilla bigelowi is mainly active during the day; it may sing through the night on warm nights only. It is a frost tolerant species; adults often survive winter and may be encountered at any time of the year. Bobilla bigelowi is generally found on ground with a high level of humidity. It forms mixed populations with B. nigrova and with species in the genus Pteronemobius , with which it can easily be confused.

Distribution

All of New Zealand except for Rakiura / Stewart Island, Chatham Islands and subantarctic islands ( Fig. 38B ).

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. 12. Bobilla bigelowi (Swan, 1972). A. Winged adult ♂, dorsal view. Lake Ōhau, Mackenzie Country (MPN OR0437). B. Dorsal view of adult ♀ with short forewings. Tumbledown Bay, Banks Peninsula (MPN OR0174). C. Adult ♂, lateral view. Little Manganuku Stream, Bay of Plenty (MPN OR0470). Scale bars = 2 mm.

Fig. 13. Bobilla bigelowi (Swan, 1972). A–B. Lateral and frontal view of head, adult ♀. Jacks Pass, North Canterbury (MPN OR0185). C. Dorsal view of right forewing in adult ♂. Lake Ōhau, Mackenzie Country (MPN OR0436). D. Male genitalia, external view, dorsal. Tumbledown Bay, Banks Peninsula (MPN OR0180). E. Egg. Mt Hutt, Canterbury (MPN OR0184). F–G. Apex of ovipositor, dorsal view, showing weak denticulation on lateral valves (F. MPN OR0153; G. MPN OR0174). H. Ovipositor, lateral view. Tumbledown Bay, Banks Peninsula (MPN OR0174). Scale bars = 500 μm.

Fig. 14. Bobilla bigelowi (Swan, 1972) song, recorded in the field at 22°C. Whangārei, Northland. A. Spectrogram of a sequenceof three chirps. B. Oscillogram of a sequence of threechirps. C. Oscillogram of one chirp consisting of eleven pulses. D. Power spectrum of one chirp.

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.