Two or three Blue-winged Locusts are none too many for a Decticus’ daily ration. It all goes down, save the wings and wing-cases, which are disdained as too tough. In addition, there is a snack of tender millet-grains stolen every now and again to make a change from the banquet of game. They are big eaters, are my boarders; they surprise me with their gormandizing and even more with their easy change from an animal to a vegetable diet.
With their accommodating and anything but particular stomachs, they could render some slight service to agriculture, if there were more of them. They destroy the Locusts, many of whom, even in our fields, are of ill fame; and they nibble, amid the unripe corn, the seeds of a number of plants which are obnoxious to the husbandman.
But the Decticus’ claim to the honours of the vivarium rests upon something much better than his feeble assistance in preserving the fruits of the earth: in his song, his nuptials [[218]]and his habits we have a memorial of the remotest times.
How did the insect’s ancestors live, in the palæozoic age? They had their crude and uncouth side, banished from the better-proportioned fauna of to-day; we catch a vague glimpse of habits now almost out of use. It is unfortunate for our curiosity that the fossil remains are silent on this magnificent subject.
Luckily we have one resource left, that of consulting the successors of the prehistoric insects. There is reason to believe that the Locustids[4] of our own period have retained an echo of the ancient customs and can tell us something of the manners of olden time. Let us begin by questioning the Decticus.
In the vivarium the sated herd are lying on their bellies in the sun and blissfully digesting their food, giving no other sign of life than a gentle swaying of the antennæ. It is the hour of the after-dinner nap, the hour of enervating heat. From time to time a male gets up, strolls solemnly about, raises his wing-cases slightly and utters an occasional [[219]]tick-tick. Then he becomes more animated, hurries the pace of his tune and ends by grinding out the finest piece in his repertoire.
Is he celebrating his wedding? Is his song an epithalamium? I will make no such statement, for his success is poor if he is really making an appeal to his fair neighbours. Not one of his group of hearers gives a sign of attention. Not a female stirs, not one moves from her comfortable place in the sun. Sometimes the solo becomes a concerted piece sung by two or three in chorus. The multiple invitation succeeds no better. True, their impassive ivory faces give no indication of their real feelings. If the suitors’ ditty indeed exercises any sort of seduction, no outward sign betrays the fact.
According to all appearances, the clicking is addressed to heedless ears. It rises in a passionate crescendo until it becomes a continuous rattle. It ceases when the sun vanishes behind a cloud and starts afresh when the sun shows itself again; but it leaves the ladies indifferent.
She who was lying with her shanks outstretched on the blazing sand does not change her position; her antennary threads [[220]]give not a quiver more and not a quiver less; she who was gnawing the remains of a Locust does not let go the morsel, does not lose a mouthful. To look at those heartless ones, you would really say that the singer was making a noise for the mere pleasure of feeling himself alive.
It is a very different matter when, towards the end of August, I witness the start of the wedding. The couple finds itself standing face to face quite casually, without any lyrical prelude whatever. Motionless, as though turned to stone, with their foreheads almost touching, the two exchange caresses with their long antennæ, fine as hairs. The male seems somewhat preoccupied. He washes his tarsi; with the tips of his mandibles he tickles the soles of his feet. From time to time he gives a stroke of the bow: tick; no more.