Cricket belonging to the genus Gryllus. Male of Field cricket (G. campestris). Photo: Rūta Starka.
Singing under the rain…
Male crickets, which have not been castrated, typically produce their characteristic songs when environmental conditions, particularly temperature and humidity, are optimal. This acoustic signal serves a crucial purpose in cricket reproduction. Upon hearing these songs, female crickets become receptive to mating. Interestingly, this auditory stimulation is so effective that it can even work through artificial means. A pioneering study conducted by Regen in 1913 demonstrated that female crickets could become receptive to mating calls transmitted via telephone communication. This finding highlights the significance of auditory cues in cricket mating behavior and the remarkable sensitivity of female crickets to these acoustic signals. This phenomenon underscores the intricate relationship between environmental factors, male cricket songs, and female cricket responses in the reproductive cycle of these insects.
While the primary and most extensively researched function of insect songs is to facilitate mating by attracting members of the opposite sex, these acoustic signals serve several other important communicative purposes:
- Mate attraction: The most well-known function, where songs help bring males and females together for reproduction.
- Male rivalry: Songs can be used in competitive interactions between males, possibly to establish dominance or territorial boundaries.
- Group cohesion: Some species use their songs to maintain social bonds and coordinate group activities within their populations.
- Alarm signals: Certain acoustic emissions serve as warning calls, triggering flight reactions in response to perceived dangers.
Field Cricket vs Two-spotted Cricket
To distinguish between Field Cricket (Gryllus campestris) and Two-spotted, or Mediterranean, Cricket (Gryllus bimaculatus), a detailed analysis of their sounds is necessary, as the human ear alone is often insufficient to differentiate between these two species.
When examining 25-second oscillograms of both species, the differences are not immediately apparent. Both produce a “chirp, chirp” sound with a rhythm (echemes per second) that varies depending on temperature, and an amplitude that changes based on the observer’s distance from the insect.
The sonograms and songs of both Gryllus species are very similar.
However, the distinction becomes clearer when observing more in detail the oscillograms (expanded to 3 seconds) and focusing on one echeme. This subtle difference in the amplitude pattern of syllables within each chirp is key to distinguishing between these two cricket species. While they may sound similar to the casual listener, these acoustic nuances reveal their distinct identities when analyzed more closely.
Gryllus campestris
The field cricket (Gryllus campestris) is a common European species known for its distinctive chirping song, which males produce by rubbing their forewings together to attract females during the mating season. Check in Xeno Canto the full record by Cesare Brizio here.
Gryllus campestris: increasing amplitude within each echeme / chirp pattern. Photo: Roberto .
Gryllus bimaculatus
Gryllus bimaculatus: the song exhibits relatively consistent amplitude within each echeme. Photo Carlos Álvarez.
Rafa Carbonell is author of the first audio guide published in Spain dedicated to the orthopteran and cicada are heard more commonly, with 50 species and 5 soundscapes. Click here to purchase the guide.
Carbonell, R. & E. Matheu 2010. Guia Sonora dels insects de Catalunya. Grills, saltamartins i cigales. Publisher: Alosa, sons de la natura, Barcelona.
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