Cricket songs keep precise pulses while pauses vary
A single peer-reviewed acoustic study found that male crickets keep the timing of individual sound pulses much steadier than the pauses between chirps. European and Japanese laboratory lines also differed in pulse timing and sound frequency. Males that could hear each other did not coordinate their calls in the tested conditions, so precise individual rhythms did not amount to a synchronized chorus.
Science··Night
Fast pulses sit inside slower chirps
Male Gryllus bimaculatus crickets make their calling sound by rhythmically moving their forewings. A single peer-reviewed Scientific Reports study by Berthold Hedwig compared the timing of those calls. Short sound pulses cluster into chirps, separated by silent gaps. A chirp commonly contained three to six pulses. Pulse rates ranged from 26 to 36 Hz, while chirps occurred at around three per second. Calling could become steadier after a hesitant start to the night.[1]
Timing differs between laboratory lines
The spacing of individual pulses varied by milliseconds or less, considerably less than the gaps between chirps. Stable recordings came from thirteen males in a European laboratory line and nine in a Japanese line. The insects were housed separately at 24 °C under a regular cycle of light and darkness. Japanese males had shorter pulses and a higher calling frequency. Recordings on multiple nights also captured variation within the same individual.[1]
Neighbors keep their own rhythms
Paired tests placed the openings of two containers thirty centimetres apart. Separate microphones helped assign pulses to each male. Hearing a neighbor did not prompt the males to match their pulse or chirp timing. These laboratory observations provided no support for coordinated choruses or alternating calls. Differences between the European and Japanese lines were discussed as possible signs of geographic divergence; the acoustic comparison did not directly demonstrate the formation of separate species.[1]
