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irregular-trilling field cricket

Gryllus cohni Weissman 1980

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map holotype male holotype male female
54 s of calling, from Pima County, Ariz., 25.3°C. Dominant frequency 4.8 kHz. Recording by D.B. Weissman (S15-108, R15-289); used by permission. Click on sound bar to hear entire recording.
This sound spectrogram is a 10 s excerpt of the 54 s audio file accessible above. The excerpt begins at 40 s. Click on sound bar to hear graphed song.
Sound spectrogram showing first 8 chirps of 10 s sample above. Click on sound bar to hear graphed song.
Song: Weissman and Gray (2019) described the song as an irregular trill with 1-13 pulses, pulse rate 22-41 per second at 25°C. Songs may be long, uninterrupted trills or have sections where the pulses are clustered in threes.
Identification: Small to medium body with a small head. Somewhat hirsute and dull pronotum. Typically long hind wings.
DNA: Gryllus cohni is sister species to G. vocalis. Gryllus cohni has a disjunct distribution but DNA analysis shows these separated populations are indeed the same species. For more information about DNA testing, see Weissman and Gray (2019).
Similar species: Gryllus vocalis' song consists of long uninterrupted bouts of 3 pulse chirps, has little or no variation in pulse number, and the pulses are not grouped in trills. Gryllus cohni can be distinguished from the following species by these characteristics:
G. regularis has a larger, broader size, a shiny pronotum, and short hind wings;
G. staccato has a larger size, a faster pulse rate (70-110), and variable pulses per chirp—females cannot be separated from G. cohni females except by DNA;
G. rubens has a long series (> 1 second) of regularly-spaced trills at a pulse rate <60;
G. texensis has a regularly-spaced trill at a pulse rate <70;
G. integer has a pulse rate >70;
G. armatus has different pulse and chirp rates at 25°C;
G. multipulsator females cannot be separated from G. cohni females except by DNA.
Range: South-central Arizona and in Mexico.
Habitat: Both dry (open Sonoran Desert) and wet areas inhabited by humans (lawns, base of palm trees, irrigated gardens), gas stations, cracks in structures and sidewalks and in deep, dry soil.
Life cycle: Possibly one or two generations per year, may vary due to amount of rainfall in a given year.
Season: Late March through August.
Remarks: Gryllus cohni and G. vocalis were found living in the same habitat in a semi-garden area in Ajo, Arizona. Specimens were not found on later visits to the area.

As early as 1980 David B. Weissman began publishing the results of his field and laboratory studies of the Gryllus of the United States and Canada (Weissman et al. 1980). By 2003, David Gray had started his cooperation with Weissman by providing genetic analysis of the living Gryllus made available by Weissman's studies (e.g., Weissman, Walker, and Gray 2009). Weissman and Gray's manuscript regarding the Gryllus of US and Canada was published in Zootaxa on 5 December 2019. [The manuscript will soon be made available.]
Name derivation: Named in honor of the Orthopterist Theodore J. Cohn.
More information:
subfamily Gryllinae, genus Gryllus
References: Weissman DB, Rentz DCF, Alexander RD, & Loher W. 1980, Weissman and Gray 2019
Nomenclature: OSF (Orthoptera Species File Online)
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