Gryllus cohni Weissman

Weissman, David B. & Gray, David A., 2019, Crickets of the genus Gryllus in the United States (Orthoptera: Gryllidae: Gryllinae), Zootaxa 4705 (1), pp. 1-277 : 162-168

Gryllus cohni Weissman

Irregular-Trilling Field Cricket

Figs 155–157 , 164–169 , Table 1

1980 Gryllus cohni Weissman, Transactions of the American Entomological Society 106: 339. Holotype male ( Fig. 164 ): Mexico, Baja California Sur, 0.5 km W Hwy 1 km 8 sign W La Paz, 16-vii-1978. S78-59, R78-90. Type in CAS, Entomology type # 13220.

‘ Gryllus irregularis’, G. #20 of DBW notebooks.

Arizona stutter triller of Sakaguchi & Gray (2011).

Distribution. Known from south-central Arizona and Mexican states of Sonora, Sinaloa, Nayarit, Jalisco and the Cape Area of Baja California Sur.

Recognition characters and song. Small to medium sized, small headed, usually long hind winged, pronotum moderately hirsute and slightly dull ( Figs 164 , 165 ). Song variable, which can make for difficult identification, but usually an irregular “trill” ( Fig. 166 , 2003-295, R15-289) with groupings of 1 to 13 pulses and a PR between 22 and 41 at 25°C. Some males ( Fig. 167 , R 14-36 ) with much longer, uninterrupted trills. Some individuals, mainly from central Arizona, with sections where their pulses clustered in threes (see Fig. 167 , recording 2006-260), resembling the song of morphologically indistinguishable sister species G. vocalis . Nevertheless, songs of G. cohni can be distinguished from those of G. vocalis since the latter produces long uninterrupted bouts of 3 pulse chirps, with little or no variation in pulse number, and pulses never grouped into trills as seen in other sections of recording 2006-260. The two-sister species are also usually separated ecologically with G. vocalis around moist environs and G. cohni in drier, more open desert situations. Both taxa were found microsympatric at only one location—a semi-garden area in Ajo, AZ (S98-72), although several subsequent visits to both Ajo and Why failed to yield more specimens of either. Additionally, G. vocalis usually with short hind wings and a shiny pronotum and frequently at high densities in riparian corridors (see under G. vocalis ) while G. cohni rarely common anywhere. G. cohni distinguished from other western US trilling Gryllus species as follows: From Arizona G. regularis , which is a larger, broader cricket with a shiny pronotum and short hind wings whose pulses are uniformly spaced and not grouped; females somewhat separable by ovipositor length relative to pronotal width ( Fig. 168 ). From Arizona G. staccato , a larger cricket whose calling song can vary from an irregular trill with a faster pulse rate of 70-110, variable pulses/chirp, and different DNA. From Texas and eastward medium to large G. rubens , which has long series (> one second) of regularly-spaced trills delivered with a PR less than 60. From larger eastern New Mexico and eastward G. texensis that has regularly-spaced trills delivered with a PR>70. Rare western G. integer trill but with PR>70. Lastly, at very warm (>35°C) nighttime summer temperatures (easily reached in Ajo and Why, AZ) G. cohni males, when mainly singing with 3-4 p/c, can sound like G. armatus . They can be easily separated by recordings made closer to 25°C with differences in pulse rate and chirp rate diagnostic. Where they occur with G. multipulsator and G. staccato (e.g. near Mazatlán, S14-53), females too similar to separate except by DNA.

Specimens examined. (Total: 64♂ 27♀). MEXICO. Baja California Sur, 0.5 km W Hwy 1 km 8 sign W La Paz , 16-vii-1978 (S78-59) 3♂ (including holotype) 7♀; 31-xii-1978 (S79-16) 2♂; 21-iv-1979 (S79-84) 1♂; 25-viii-1995 (S95-81) 2♂. First wash along road to Miraflores, off Hwy 1, 24-iv-1979 (S79-95) 1♂ . Jalisco, Club Med Playa Blanca, Rincon de Careyes ~55 road km N Manzanillo , 29-xii-1984 (S85-1) 13♂ 4♀ . Puerto Vallarta , 29-iii-1983 (S83-13) 2♂ . Nayarit, Hwy 200 1.6 km NE turnoff for Alta Vista , km post 78.3, 26-vi-2011, 320’, 21° 07’ 57.4” -105° 10’ 01.3” (S11-50) 1♂ . Sinaloa, Mazatlán , 11-viii-1999 (S99-87) 1♂ . ~ 20 km S Mazatlán , 23-vii-2014, 110’, 23° 11’ 49.4” -106° 11’ 37.7” (S14-53) 6♂ 1♀ . Hwy 40 2 km NE Hwy 15, 11-viii-1999 (S99-86) 2♂ . Sonora, Alamos , 18-vii- 2006, 390m, 27.0257338° -108.9403527° ( DAG 2006-215 ) 2♂ . Hermosillo , 24-vii-1990 (S90-77) 1♂ . San Carlos Bay, Club Med , 22-29-iii-1986 (S86-15) 6♂ . 12 km W San Carlos , 25-vii-1990 (S90-78) 2♂ . USA. Arizona. Pima Co., Ajo , north end town, 520m, 20-viii-1998 (S98-74) 6♂ . Ajo , plaza area, 520m, 20-viii-1998 (S98-72) 2♂ . Sells , 29-vii-2015 (S15-107) 1♂ . Why , 530m, 20-viii-1998 (S98-71) 1♂ 6♀ . Hwy 86 4.4 m NW Sells , 31° 57’ 25.4” -111° 56’ 46.4” 2276’, 29-vii-2015 (S15-108) 1♂. Yavapai Co., Agua Fria National Monument, Perry Mesa near intersection Bloody Basin Rd and Pueblo La Plata Rd, 3657’, 34° 14’ 8.56” -112° 01’ 45.34”, 16-viii- 2006, DAG 2006-243, 4♂ , 1 last instar male and 1 last instar female; 11-ix-2007, 1♂ 1♀; 11-ix-2012 6♀ . Forest Service Road 525 west of Sedona , 4507’, 16-viii-2004, 34.91855° -111.91090° 2♀ , I17 near Cordes Junction , gas station, 6-viii-2003, 34° 19’ 41.6” -112° 07’ 8.3” ( DAG 2003-294 , 2003-295 ) 3♂ .

Song records only. MEXICO. Sinaloa, Concordia, 320’, 11-viii-1999 (S99-85) 2♂ . El Fuerte, 23-vii-2006, 800’, 26.42099° -108.61774° (2006-224) 1♂.

Uncertain placement. Arizona: Pima Co., Ajo , plaza area, 520m, 20-viii-1998 (S98-72) 1♂ (R98-28). This long hind winged male has 3p/c delivered evenly and probably represents G. vocalis . If true, this site would represent the only locality where G. cohni and G. vocalis occur microsympatrically. Hwy 86 4.4 m NW Sells, 31° 57’ 25.4” -111° 56’ 46.4”, 12276’, 29-vii-2015 (S15-108) 1♂ (R15-289, G3217). This long hind winged specimen, the only male heard here, from open Sonora Desert, sang with 3 (5) p/c. His 16S DNA mapped in the tree where G. vocalis and G. cohni are intermixed. His ITS2 gene mapped (see Fig. 157 ) with other G. cohni and separate from G. vocalis . Such a dry habitat is usually associated with G. cohni although 3 males of the more mesic associated, always long hind winged G. multipulsator were also collected there. Perhaps these individuals all flew here after a localized monsoon rain?

Derivation of name. This cricket was originally named in appreciation of Theodore J. Cohn.

Geographic range. Fig. 169 .

Habitat. From 520-1152m. The type locality is a wooded, thickly vegetated area subject to periodic flooding, where adult males did little singing and were most easily collected by an oatmeal trail. Found in both dry (open Sonoran Desert) and wet areas of human habitation, sometimes around lawns (San Carlos Bay, S86-15), at base of planted palm trees, irrigated garden areas, etc. Also at gas stations (Mazatlán, S99-87), cracks in structures and sidewalks and in deep, dry soil cracks (the latter away from human habitation at Agua Fria).

Life cycle and seasonal occurrence. Egg diapause absent (Agua Fria). Unsure if 1 or 2 generations/year and may vary between years depending on rainfall. Adults known from late March (San Carlos Bay, S86-15) through August. Nymphs collected at Agua Fria 16-viii-2006 (2006-257 & 2006-260). We have collected the Ajo-Why area on other occasions (16-v-1999 and 17-ix-2011) besides those listed under “Specimens examined” and not heard any G. cohni singing. Likewise collecting the Yavapai Co. localities of Agua Fria and Cordes Junction on 18-ix-2011, 12-vi-2012, 21-viii-2012, and 31-v-2013 yielded no singing males. There appears to be some unexamined interaction between monsoon rainfall and which Gryllus species are present, and when, in many areas of south-central Arizona. Despite collecting 6 G. cohni males, flushed with water from a grassy area, none were heard singing at 20 km S Mazatlán (S14-53) when we arrived at 11:20 PM with temperatures at 31°C.

One question stands out: how long are Gryllus eggs viable in the soil, especially during periods of below average summer monsoon and winter rainfall?

Variation. Head width: All Mexican specimens from Playa Blanca (S85-1) and Puerto Vallarta (S83-13) with head narrower than pronotum, a condition infrequently seen in US specimens. Hind wing length: Of 39 individuals of G. cohni from Mexico, 37 have long hind wings and 2 males are dealate. In southern Arizona (Ajo and Why), all 13 collected individuals were long winged. In contrast, of the 7♂ and 8♀ from the Agua Fria National Monument area in north/central Arizona, 14 had short hind wings. Body size: Males from Agua Fria as small as 15.8 mm body length. In our small sample from Baja California Sur, Mexico, (Weissman et al. 1980), females were consistently larger than males, a characteristic also seen in those individuals from the Agua Fria area. Song: Number of p/c characteristically variable. Of 18 recorded males, 15 had an irregular trill with the exceptions being the single Nayarit (S11-50) specimen and 2 of 6 males from Mazatlán (S14-53). The Nayarit male was recorded twice: he had a short introductory trill and then groupings of 3-6 p/c at 27°C on 5-vii-2011, and no introductory trill with 3 or 4 p/c at 26° on 9-vii -2011. His DNA (G2074) mapped with that of other G. cohni . Of the 6 Mazatlán males (S14-53), 4 had an irregular trilling pattern ( Fig. 167 , R 14-30 ) and 2 trilled more regularly ( Fig. 167 , R 14-36 ). In southern Arizona (Ajo and Why), all 6 recorded males produced an irregular trill. Songs from Agua Fria were different from the general pattern seen in Mexico and southern Arizona in that some had significant stretches of 3p/c ( Fig. 155 , R 15 -289) in addition to periods of irregular trills. Our documentation (Weissman et al. 1980, Fig 10a, b ) in Baja California, where calling songs at higher temperatures tended to go from discrete bursts to longer trains of trills, has not been seen in populations elsewhere.

DNA. Multilocus G101, Baja California, type locality (S95-81); G2776 Mazatlán, Mexico (S14-53); and 2016- 041 Agua Fria National Monument are all sisters to 2016-036, Los Angeles Co., type locality of G. vocalis ; G3335, Albuquerque, NM, type locality of G. alogus ; and G3227 from Gila Bend , AZ (S15-111), locality of ‘G. arizonensis’ (Gray et al. 2019) (and see under G. vocalis for discussion of G. alogus and ‘ G. arizonensis’). We caution that type locality leg G101, used in both 16S and multilocus sequencing, was removed in 2003 from a pinned specimen, eight years after collection. In both sequences, the leg mapped consistent with other G. cohni and sister species G. vocalis specimens.

Discussion. Of the US species discussed in this paper, G. cohni is the only one whose type locality is in Mexico. Because of its disjunct distribution ( Fig. 169 ), we were initially uncertain if we were dealing with one taxon. But we were unable to separate, morphologically and song-wise, those from the Cape Area of Baja California Sur from those on the adjacent Mexican mainland and those from Arizona. Most importantly, 3 geographically separated samples of G. cohni (from Baja Sur, Sinaloa, and Arizona) map together and are well supported for both ITS2 ( Fig. 157 , p. 155 ) and in the multilocus genetic analysis (Gray et al. 2019). Also, 3 geographically separated, and well supported samples of G. vocalis (from Los Angeles, Albuquerque, and Arizona) map together ( Fig. 157 ) and separate from sister species G. cohni .

We wonder if some variation on this possible historic narrative might have occurred in central Arizona to explain the complicated situation re hind wing length and songs containing 3 pulses/chirp: long hind winged (and probably able to fly), irregular trilling G. cohni typically is a cricket of dry habitats (before the summer monsoon rains come) and would not normally occur microsympatrically with usually short hind winged, 3p/c G. vocalis , since the latter prefers riparian areas in the Southwest. The spread of human habitation and the formation of cities like Ajo and Why, AZ, subsequently brought these two environments into proximity, which brought these two-sister species together and possibly facilitated hybridization and introgression. Thus, we find around central Arizona, short hind winged crickets that sing like G. cohni but also have periods of 3p/c in their calling songs as seen in G. vocalis . Consistent with this narrative is the fact that no G. vocalis are known along northern Sea of Cortez mainland Mexico and, hence, the widespread absence there of G. cohni with 3p/c song-periods. We have no data to support this scenario, but it is in principle easily testable using modern genomics.

Likewise, in this general Arizona geographical area, we find (normally rare elsewhere) long hind winged G. vocalis at Cottonwood Cove, NV (S81-31); Goodyear (S81-46), Buckeye (S11-102), and Gila Bend (S09-103), AZ; and Havasu Lake, CA (S83-62), although none have periods of trilling, regular or irregular song.

Given the variation in song produced by males in the same population, this species would be ideal for studies on female song preferences.

One male each from S86-15 (San Carlos Bay) and 2006-243 (Agua Fria) parasitized by tachinid Ormia ochracea . At the first locality, all 3 Gryllus species there ( multipulsator , staccato , and cohni ) were parasitized by this tachinid species.

Figures

FIGURE 10. Populations of Acheta domesticus that we studied.

FIGURE 14. Head on view of male G. locorojo showing head stripes.

FIGURE 15. Five second calling song of G. locorojo: (R12-3) commercial pet store, at 22°C.

FIGURE 16. One second spectrogram of G. locorojo, same male as in Fig. 15.

FIGURE 17. ITS2 gene tree. G. brevicaudus samples: S03-8 (G5); S16-1 (G3354, G3393); G. insularis samples: Guadalupe Island, Baja California Norte, Mexico; G. bryanti samples: Andros Island, Bahamas; G. alexanderi sample: Clarion Island, Colima, Mexico.

FIGURE 18. Holotype male, and labels, of G. brevicaudus.

FIGURE 19. Top: Live male (Jasper Ridge, S92-44) G. brevicaudus showing distinctive yellow-orange markings that contrast with rest of black cricket. Bottom: Female from Palo Alto, CA (S87-33) showing short ovipositor.

FIGURE 20. Five second waveform (A) and one second spectrogram (B) of calling song (R03-8) of G. brevicaudus from San Benito Co., CA (S03-8), recorded at 24.5°C.

FIGURE 21. Known distribution for G. brevicaudus. Star shows type locality.

FIGURE 22. Left Panel: G. bryanti (on left) vs. sympatric G. assimilis (right), both from Bahamas. Note head wider than pronotum in G. bryanti. Right Panel: Three second waveform of typical single-pulse chirp calling song of G. bryanti (neotype male, GBM08, Andros Island, at 25 °C).

FIGURE 23. Male holotype (right) and female allotype (left) G. ovisopis.

FIGURE 24. Holotype male (left), G. thinos. Female (right) from type locality showing typical, linear head stripes.

FIGURE 25. Calling song of G. thinos (R07-125) Cameron Co., TX (S07-25), at 25°C: (A) five second waveform, (B) one second spectrogram.

FIGURE 26. Known distribution of G. thinos.

FIGURE 27. ITS2 gene tree showing some separation between Padre Island and Boca Chica samples of G. thinos.

FIGURE 28. Five second waveforms of calling songs of (A) G. pennsylvanicus and (B) G. firmus. G. pennsylvanicus (R04-110) Whatcom Co., WA (S04-91), at 25°C. G. firmus: (R03-255) Gainesville, FL (S03-85), at 25°C.

FIGURE 29. One second spectrograms of (A) G. pennsylvanicus and (B) G. firmus; same males as in Fig. 28.

FIGURE 30. ITS2 gene tree. G. firmus samples: S03-85 (G60, G61, G62); S07-25 (G1073, G1074); S07-26 (G1186, G1235); S10-63 (G1920, G1922); S10-67 (G1915); S11-29 (G2165, G2029, G2034); S13-41 (G2709); S13-59 (G2716); G. pennsylvanicus samples: S08-74 (G709, G710); S11-107 (G2208); S11-108 (G2211).

FIGURE 31. Five second calling song of G. pennsylvanicus (R04-110) Whatcom Co., WA (S04-91), at 25°C.

FIGURE 32. Populations of G. pennsylvanicus studied by us.

FIGURE 33. Size differences, in G. pennsylvanicus, between northern (right) from Berrien Co., Michigan, and southern (left) from Saline Co., KS [S02-49]).

FIGURE 34. Map of G. pennsylvanicus showing variation in file tooth number across the United States. File teeth range from 124 (Vancouver, S00-54)) to 223 (Oklahoma City, S02-48).

FIGURE 35. Long ovipositor G. pennsylvanicus from Saline Co., KS (S02-49).

FIGURE 36. Regression G. pennsylvanicus showing a weak correlation between number of file teeth and hind femur length, the latter a proxy for body size.

FIGURE 155. Five second waveforms of calling songs of (A) typical G. cohni and (B) G. vocalis. G. cohni: (R15-289) Pima Co., AZ (S15-108), at 25.3°C; G. vocalis: (R09-17) San Diego Co., CA (S09-18), at 23.5°C.

FIGURE 156. One second spectrograms of (A) G. cohni and (B) G. vocalis, same males as in Fig. 155.

FIGURE 157. ITS2 gene tree. G. cohni samples: S95-81 (G102); S14-53, 20 km S Mazatlán, Mexico (G2756, G2757, G2776, G2843,G2844, G2846); S15-107 (G3248); S15-108 (G3217);Cordes Junction,Yavapai Co.,AZ (2003-294, 2003-295A); Bloody Basin x Pueblo la Plata, Agua Fria National Monument, Yavapai Co., AZ (2006-248). G. vocalis samples: S05-68 (G487); S05- 99 (G505); S11-102 (G2185); S12-20 (G2244); S12-26 (G2265); S13-13 (G2531); S13-14 (G2479); S13-16 (G2481); S15-110 (G3215); S15-111 (G3219, G3224, G3227, G3290, G3291); S16-18 (G3405); S16-28 (G3423); Wet Beaver Creek Campground, Yavapai Co., AZ (2007-172, 2007-174); California State University Northridge, Los Angeles Co., CA (2016-043). G. alogus, type locality, Albuquerque, NM (G3335, G3337).

FIGURE 164. Holotype male of G. cohni, with labels.

FIGURE 165. Female G. cohni from Pima Co, AZ (S98-71).

FIGURE 166. ‘Typical’ songs of G. cohni illustrating the extreme variability in pulse numbers both within and among individuals. (A) 2003-295 Cordes Junction, Yavapai Co., AZ, at 22.0°C. (B) R15-289 Pima Co., AZ (S15-108), at 25.3°C.

FIGURE 167. One second spectrograms of G. cohni showing atypical calling songs. (A) Agua Fria, AZ (2006-260), showing pulses grouped into 3s, at 22.8°C. (B) near Mazatlán, Mexico (R14-30, S14-53), showing an irregular trilling pattern, at 26°C. (C) near Mazatlán, Mexico (R14-36, S14-53), showing an almost uninterrupted trill, at 25.7°C.

FIGURE 168. In sympatry in central Arizona, female G. cohni and G. regularis differ in relative ovipositor length, however not diagnostically so. All females are from Agua Fria National Monument, with species ID via song of lab reared sons.

FIGURE 169. Known distribution of G. cohni.