Ever since the end of May on nights when it is warm and wet, the rainforest pulses with what seems to be a continual din of cricket song.
The songster is a short-winged field cricket, Cephalogryllus species.
This is a pretty large cricket, measuring about 25 mm in length. They seem to be quite common but localised to some extent with small aggregations here and there.
They are subterranean. Males sing from the burrow entrances after dark on nights when the humidity and temperature is to their liking. It seems that they are silent when the temperature drops to 14C. The short wings serve only to produce the song. They are too short for flight.
You can hear a recording of this species at:
Although the loud sounds coming from these crickets reminds one of a continuous calling tree cricket (Oecanthinae), the individual calls are just long trills followed by a pause. But they are not co-ordinated so the result to the ear is a continuous trill. They are highly ventriloquial and individuals are very difficult to pinpoint. Once this is successful, it is often a bit embarrassing that the calling male was so close and yet apparently "invisible".
The crickets use their heads to move soil to the surface when they are excavating, hence the origin of the generic name. I have not properly dug the burrows to reveal their structure. This is a tedious task as the burrows meander through a labyrinth of roots and stones. The few that I have dug produce only males. Several had last instar male nymphs.
The biology of these neat insects is still poorly known. They re said to drag dead leaves into their burrows. I have never seen an individual abroad at night. Baiting with an oatmeal trail has resulted in only a few cockroaches and beetles but none of these crickets. One would assume that the reason for the males' calling is to attract females. This would seem to necessitate females moving about on the surface of the ground but as noted above, females have not been found. I have checked the oatmeal at several times during the night.
Cephalogryllus crickets seem to be very common and widespread. Similar loud calls are heard each night in the rainforest across the street from the Cairns Botanical Gardens and in the forest near the Gondwanaland section
Otte, D. Alexander, R. D. 1983. The Australian Crickets (Orthoptera: Gryllidae). Academy of Natural Sciences of Philadelphia. Monograph 22Pp. 1-477.