Electronic Whistle Aids War Against Locusts

Press, Volume XCI, Issue 27637, 19 April 1955, Page 10

Electronic Whistle Aids War Against Locusts

(From a Reuter Correspondent)

PARIS. A modern Pied Piper with an electronic whistle hopes to lure to their deaths the countless millions of locusts which invade France’s North African territories.

Dr Rene Guy Busnel wants to draw the legions of grasshoppers away from the crops by broadcasting their mating call from desolate areas. Once attracted to the transmitting point, they could be slaughtered with flamethrowers or poison-spraying planes. ■ Busnel and his young Americaneducated wife Marie Claire have been working on the idea since 1948. Month after month they have conducted meticulous experiments at the National Institute of Agronomic Research under the Ministry of Agriculture. Their summer holidays have been spent in the field, stalking grasshoppers under a 104 degrees sun to record the locusts’ chirpings and study their habits.

- E Xf r since man first planted crops in the locust belt of Africa and the Middie East, he has watched the skies fearfully for the appearance of the winged plague. The number of insects m a medium-sized swarm of seven square miles can equal the total population of the world. The voracious hoppers can strip everything edible from a field of grain, tomato vines or a grove of orange or date trees in a matter of minutes.

Early this year, moving up from the sandy wastes of Mauritania, the locusts settled in the south of Morocco in the worst invasion in memory. Unprecedentedly ravenous, they crawled into the eyes, ears and mouths of children, leaving raw sores, and swarmed over living animals. They flew unheeding into smudge fires. Since then, they have appeared in the semidesert lands of nomadic herders in Southern Algeria and some have gone as far as Tunisia ®

The Busnels experiments will not be able to stem this year’s invasions and may not provide effective weapons

until the end of this decade. So far their work has been with domestic and relatively solitary insects. The scientist started working on the insects’ sensitivity to sounds and vibrations after finding that .they have bad senses of smell and sight—they are blind to objects more than a few inches away, yet can hear a sound made by one of their own kind as much as 100 times that far. “Talked” With Insects

The Busnels “talked” with their grasshoppers and crickets both by broadcasting recordings of their voices and by sending out artificial signals, electronic and mechanical. They found that in some species the mating call is sent out by the male, who waits for the female to find him. In other types the male tracks down to source the periodic call issued by. the female. They found that the frequency makes no difference to the insects, it is the modulation that counts. If a police whistle or a rattle issues a correctly moduated sound, it is as effective in attracting the hoppers as in the carefully constructed tone of an electronic speaker. But for large-scale experiments, the electronic equipment will be used because of its carrying power. The modulation will be “built” on to a bass tone since low frequencies (longer waves) carry further than high ones.

In the course of their work, the couple have made use of some strange facts about the behaviour and reactions of insects and animals to the stimulus of light and sound. Light, for example, attracts night moths, while it immobilises such animals as deer, and frightens others away. The same sound which attracts grasshoppers frightens off starlings, and has been used to clear buildings of flocks of these problem birds. Some moths have “radar receivers” which pick up the radar-like emissions which bats use to navigate, enabling them to hide when they detect the approach of hunting bats.