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).