Social Life in the Insect World

by Jean-Henri Fabre

For their maintenance a wire-gauze cover suffices, with a bed of sand and diet to their taste. They are very small, scarcely larger than a cherry-stone. Their shape is extremely curious. The body is dumpy, tapering to an acorn-shaped posterior; the legs are very long, resembling those of the spider when outspread; the hinder legs are disproportionately long and curved, being thus excellently adapted to enlace and press the little pilule of dung.

Mating takes place towards the beginning of May, on the surface of the soil, among the remains of the sheep-dung on which the beetles have been feeding. Soon the moment for establishing the family arrives. With equal zeal the two partners take part in the kneading, transport, and baking of the food for their offspring. With the file-like forelegs a morsel of convenient size is shaped from the piece of dung placed in the cage. Father and mother manipulate the piece together, striking it blows with their claws, compressing it, and shaping it into a ball about the size of a big pea.

As in the case of the Scarabæus sacer, the exact spherical form is produced without the mechanical device of rolling the ball. Before it is moved, even before it is cut loose from its point of support, the fragment is modelled into the shape of a sphere. The beetle as geometer is aware of the form best adapted to the long preservation of preserved foods.

The ball is soon ready. It must now be forced to acquire, by means of a vigorous rolling, the crust which will protect the interior from a too rapid evaporation. The mother, recognisable by her slightly robuster body, takes the place of honour in front. Her long hinder legs on the soil, her forelegs on the ball, she drags it towards her as she walks backwards. The father pushes behind, moving tail first, his head held low. This is exactly the method of the Scarabæus beetles, which also work in couples, though for another object. The Sisyphus beetles harness themselves to provide an inheritance for their larvæ; the larger insects are concerned in obtaining the material for a banquet which the two chance-met partners will consume underground.

The couple set off, with no definite goal ahead, across the irregularities of the soil, which cannot be avoided by a leader who hauls backwards. But even if the Sisyphus saw the obstacles she would not try to evade them: witness her obstinate endeavour to drag her load up the wire gauze of her cage!

A hopeless undertaking! Fixing her hinder claws in the meshes of the wire gauze the mother drags her burden towards her; then, enlacing it with her legs, she holds it suspended. The father, finding no purchase for his legs, clutches the ball, grows on to it, so to speak, thus adding his weight to that of the burden, and awaits events. The effort is too great to last. Ball and beetle fall together. The mother, from above, gazes a moment in surprise, and suddenly lets herself fall, only to re-embrace the ball and recommence her impracticable efforts to scale the wall. After many tumbles the attempt is at last abandoned.

Even on level ground the task is not without its difficulties. At every moment the load swerves on the summit of a pebble, a fragment of gravel; the team are overturned, and lie on their backs, kicking their legs in the air. This is a mere nothing. They pick themselves up and resume their positions, always quick and lively. The accidents which so often throw them on their backs seem to cause them no concern; one would even think they were invited. The pilule has to be matured, given a proper consistency. In these conditions falls, shocks, blows, and jolts might well enter into the programme. This mad trundling lasts for hours and hours.

Finally, the mother, considering that the matter has been brought to a satisfactory conclusion, departs in search of a favourable place for storage. The father, crouched upon the treasure, waits. If the absence of his companion is prolonged he amuses himself by rapidly whirling the pill between his hind legs, which are raised in the air. He juggles with the precious burden; he tests its perfections between his curved legs, calliper-wise. Seeing him frisking in this joyful occupation, who can doubt that he experiences all the satisfactions of a father assured of the future of his family? It is I, he seems to say, it is I who have made this loaf, so beautifully round; it is I who have made the hard crust to preserve the soft dough; it is I who have baked it for my sons! And he raises on high, in the sight of all, this magnificent testimonial of his labours.

But now the mother has chosen the site. A shallow pit is made, the mere commencement of the projected burrow. The ball is pushed and pulled until it is close at hand. The father, a vigilant watchman, still retains his hold, while the mother digs with claws and head. Soon the pit is deep enough to receive the ball; she cannot dispense with the close contact of the sacred object; she must feel it bobbing behind her, against her back, safe from all parasites and robbers, before she can decide to burrow further. She fears what might happen to the precious loaf if it were abandoned at the threshold of the burrow until the completion of the dwelling. There is no lack of midges and tiny dung-beetles—Aphodiinæ—which might take possession of it. It is only prudent to be distrustful.

So the ball is introduced into the pit, half in and half out of the mouth of the burrow. The mother, below, clasps and pulls; the father, above, moderates the jolts and prevents it from rolling. All goes well. Digging is resumed, and the descent continues, always with the same prudence; one beetle dragging the load, the other regulating its descent and clearing away all rubbish that might hinder the operation. A few more efforts, and the ball disappears underground with the two miners. What follows will be, for a time at least, only a repetition of what we have seen. Let us wait half a day or so.