The Last song of Summer

My friend Jack Hasenpusch told me once that the loud calling song of the Mundurra Balloon Katydid, Hexacentrus mundurra Rentz, signified the end of summer to him. These katydids can be heard calling deep within tall grasses in the tropics late in the wet season. They are seldom found singing from more than 75 cm off the ground and they usually perch head downwards. But this year was different. They started calling very early. I heard the sounds of these katydids in early December at Aloomba, south of Cairns. I had not heard them so early before.

On cool nights males commence the Calling Song with a series of buzzes. It is believed that this is a "warm-up", warming the muscles for the blast that is to follow. There is a brief pause after the warm-up buzzes and then the body of the song. It is loud and easily heard from a moving car. Other species of Hexacentrus have very low calls, scarcely audible from 2m distant, but not this species. It's loud call makes it very easy to sample its distribution.

The Mundurra Balloon-winged katydid is a predator. Other katydids or grasshoppers seem to be the preferred foods. This katydid is one of 24 in the genus Hexacentrus scattered throughout the Pacific, Africa and Asia. Many, but not all, occur in tropical climes. All have distinctive calling songs but none that I know of are as loud as H. mundurra.

Females present a different appearance from the males. The wings are held close to the body and, of course, they have a long ovipositor. Females are very difficult to locate. They seem to prefer to maraud deep in the grass, hunting for other katydids, grasshoppers and beetles. Eggs are laid in the soil and hatch the following spring.

In Volume 3 of my Monograph of the Tettigoniidae of Australia, Rentz (2001), I provided the known distribution of the species. On the east coast, populations start south of the Tropic of Capricorn, near Bundaberg, Qld. and extend north in a continuous band right across the top end of the continent and south to north of Broome, W. A. Further work needs to be done to refine the western limits of the distribution of the species. There are no authentic accounts of H. mundurra in New Guinea and, perhaps, publication of this sound recording may help to determine if anyone has heard it there. Other Hexacentrus species are found in New Guinea.

Literature

Rentz, D. C. F.2001. Tettigoniidae of Australia. Volume 3. The Listroscelidinae, Tympanophorinae, Meconematinae and Microtettigoniinae. CSIRO Publications, Collingwood, Vic. Pp. 1-524.