THE SISYPHUS BEETLE.—THE INSTINCT OF PATERNITY

The duties of paternity are seldom imposed on any but the higher animals. They are most notable in the bird; and the furry peoples acquit themselves honourably. Lower in the scale we find in the father a general indifference as to the fate of the family. Very few insects form exceptions to this rule. Although all are imbued with a mating instinct that is almost frenzied, nearly all, when the passion of the moment is appeased, terminate then and there their domestic relations, and withdraw, indifferent to the brood, which has to look after itself as best it may.

This paternal coldness, which would be odious in the higher walks of animal life, where the weakness of the young demands prolonged assistance, has in the insect world the excuse that the new-born young are comparatively robust, and are able, without help, to fill their mouths and stomachs, provided they find themselves in propitious surroundings. All that the prosperity of the race demands of the Pierides, or Cabbage Butterflies, is that they should deposit their eggs on the leaves of the cabbage; what purpose would be served by the instincts of a father? The botanical instinct of the mother needs no assistance. At the period of laying the father would be in the way. Let him pursue his flirtations elsewhere; the laying of eggs is a serious business.

In the case of the majority of insects the process of education is unknown, or summary in the extreme. The insect has only to select a grazing-ground upon which its family will establish itself the moment it is hatched; or a site which will allow the young to find their proper sustenance for themselves. There is no need of a father in these various cases. After mating, the discarded male, who is henceforth useless, drags out a lingering existence of a few days, and finally perishes without having given the slightest assistance in the work of installing his offspring.

But matters are not everywhere so primitive as this. There are tribes in which an inheritance is prepared for the family which will assure it both of food and of shelter in advance. The Hymenoptera in particular are past-masters in the provision of cellars, jars, and other utensils in which the honey-paste destined for the young is stored; they are perfect in the art of excavating storehouses of food for their grubs.

This stupendous labour of construction and provisioning, this labour that absorbs the insect's whole life, is the work of the mother only, who wears herself out at her task. The father, intoxicated with sunlight, lies idle on the threshold of the workshop, watching the heroic female at her work, and regards himself as excused from all labour when he has plagued his neighbours a little.

Does he never perform useful work? Why does he not follow the example of the swallows, each of whom brings a fair share of the straw and mortar for the building of the nest and the midges for the young brood? No, he does nothing; perhaps alleging the excuse of his relative weakness. But this is a poor excuse; for to cut out little circles from a leaf, to rake a little cotton from a downy plant, or to gather a little mortar from a muddy spot, would hardly be a task beyond his powers. He might very well collaborate, at least as labourer; he could at least gather together the materials for the more intelligent mother to place in position. The true motive of his idleness is ineptitude.

It is a curious thing that the Hymenoptera, the most skilful of all industrial insects, know nothing of paternal labour. The male of the genus, in whom we should expect the requirements of the young to develop the highest aptitudes, is as useless as a butterfly, whose family costs so little to establish. The actual distribution of instinct upsets our most reasonable previsions.

It upsets our expectations so completely that we are surprised to find in the dung-beetle the noble prerogative which is lacking in the bee tribe. The mates of several species of dung-beetle keep house together and know the worth of mutual labour. Consider the male and female Geotrupes, which prepare together the patrimony of their larvæ; in their case the father assists his companion with the pressure of his robust body in the manufacture of their balls of compressed nutriment. These domestic habits are astonishing amidst the general isolation.

To this example, hitherto unique, my continual researches in this direction permit me to-day to add three others which are fully as interesting. All three are members of the corporation of dung-beetles. I will relate their habits, but briefly, as in many respects their history is the same as that of the Sacred Scarabæus, the Spanish Copris, and others.

The first example is the Sisyphus beetle (Sisyphus Schæfferi, Lin.), the smallest and most industrious of our pill-makers. It has no equal in lively agility, grotesque somersaults, and sudden tumbles down the impossible paths or over the impracticable obstacles to which its obstinacy is perpetually leading it. In allusion to these frantic gymnastics Latreille has given the insect the name of Sisyphus, after the celebrated inmate of the classic Hades. This unhappy spirit underwent terrible exertions in his efforts to heave to the top of a mountain an enormous rock, which always escaped him at the moment of attaining the summit, and rolled back to the foot of the slope. Begin again, poor Sisyphus, begin again, begin again always! Your torments will never cease until the rock is firmly placed upon the summit of the mountain.

I like this myth. It is, in a way, the history of many of us; not odious scoundrels worthy of eternal torments, but worthy and laborious folk, useful to their neighbours. One crime alone is theirs to expiate: the crime of poverty. Half a century or more ago, for my own part, I left many blood-stained tatters on the crags of the inhospitable mountain; I sweated, strained every nerve, exhausted my veins, spent without reckoning my reserves of energy, in order to carry upward and lodge in a place of security that crushing burden, my daily bread; and hardly was the load balanced but it once more slipped downwards, fell, and was engulfed. Begin again, poor Sisyphus; begin again, until your burden, falling for the last time, shall crush your head and set you free at length.

The Sisyphus of the naturalists knows nothing of these tribulations. Agile and lively, careless of slope or precipice, he trundles his load, which is sometimes food for himself, sometimes for his offspring. He is very rare hereabouts; I should never have succeeded in obtaining a sufficient number of specimens for my purpose but for an assistant whom I may opportunely present to the reader, for he will be mentioned again in these recitals.

This is my son, little Paul, aged seven. An assiduous companion of the chase, he knows better than any one of his age the secrets of the Cigale, the Cricket, and especially of the dung-beetle, his great delight. At a distance of twenty yards his clear sight distinguishes the refuse-tip of a beetle's burrow from a chance lump of earth; his fine ear will catch the chirping of a grasshopper inaudible to me. He lends me his sight and hearing, and I in return make him free of my thoughts, which he welcomes attentively, raising his wide blue eyes questioningly to mine.

What an adorable thing is the first blossoming of the intellect! Best of all ages is that when the candid curiosity awakens and commences to acquire knowledge of every kind. Little Paul has his own insectorium, in which the Scarabæus makes his balls; his garden, the size of a handkerchief, in which he grows haricot beans, which are often dug up to see if the little roots are growing longer; his plantation, containing four oak-trees an inch in height, to which the acorns still adhere. These serve as diversions after the arid study of grammar, which goes forward none the worse on that account.

What beautiful and useful knowledge the teaching of natural history might put into childish heads, if only science would consider the very young; if our barracks of universities would only combine the lifeless study of books with the living study of the fields; if only the red tape of the curriculum, so dear to bureaucrats, would not strangle all willing initiative. Little Paul and I will study as much as possible in the open country, among the rosemary bushes and arbutus. There we shall gain vigour of body and of mind; we shall find the true and the beautiful better than in school-books.

To-day the blackboard has a rest; it is a holiday. We rise early, in view of the intended expedition; so early that we must set out fasting. But no matter; when we are hungry we shall rest in the shade, and you will find in my knapsack the usual viaticum—apples and a crust of bread. The month of May is near; the Sisyphus should have appeared. Now we must explore at the foot of the mountain, the scanty pastures through which the herds have passed; we must break with our fingers, one by one, the cakes of sheep-dung dried by the sun, but still retaining a spot of moisture in the centre. There we shall find Sisyphus, cowering and waiting until the evening for fresher pasturage.

Possessed of this secret, which I learned from previous fortuitous discoveries, little Paul immediately becomes a master in the art of dislodging the beetle. He shows such zeal, has such an instinct for likely hiding-places, that after a brief search I am rich beyond my ambitions. Behold me the owner of six couples of Sisyphus beetles: an unheard-of number, which I had never hoped to obtain.

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.

If our vigilance is not relaxed we shall see the father regain the surface alone, and crouch in the sand near the mouth of the burrow. Retained by duties in the performance of which her companion can be of no assistance, the mother habitually delays her reappearance until the following day. When she finally emerges the father wakes up, leaves his hiding place, and rejoins her. The reunited couple return to their pasturage, refresh themselves, and then cut out another ball of dung. As before, both share the work; the hewing and shaping, the transport, and the burial in ensilage.

This conjugal fidelity is delightful; but is it really the rule? I should not dare to affirm that it is. There must be flighty individuals who, in the confusion under a large cake of droppings, forget the fair confectioners for whom they have worked as journeymen, and devote themselves to the services of others, encountered by chance; there must be temporary unions, and divorces after the burial of a single pellet. No matter: the little I myself have seen gives me a high opinion of the domestic morals of the Sisyphus.

Let us consider these domestic habits a little further before coming to the contents of the burrow. The father works fully as hard as the mother at the extraction and modelling of the pellet which is destined to be the inheritance of a larva; he shares in the work of transport, even if he plays a secondary part; he watches over the pellet when the mother is absent, seeking for a suitable site for the excavation of the cellar; he helps in the work of digging; he carries away the rubbish from the burrow; finally, to crown all these qualities, he is in a great measure faithful to his spouse.

The Scarabæus exhibits some of these characteristics. He also assists his spouse in the preparation of pellets of dung; he also assists her to transport the pellets, the pair facing each other and the female going backwards. But as I have stated already, the motive of this mutual service is selfish; the two partners labour only for their own good. The feast is for themselves alone. In the labours that concern the family the female Scarabæus receives no assistance. Alone she moulds her sphere, extracts it from the lump and rolls it backwards, with her back to her task, in the position adopted by the male Sisyphus; alone she excavates her burrow, and alone she buries the fruit of her labour. Oblivious of the gravid mother and the future brood, the male gives her no assistance in her exhausting task. How different to the little pellet-maker, the Sisyphus!

It is now time to visit the burrow. At no very great depth we find a narrow chamber, just large enough for the mother to move around at her work. Its very exiguity proves that the male cannot remain underground; so soon as the chamber is ready he must retire in order to leave the female room to move. We have, in fact, seen that he returns to the surface long before the female.

The contents of the cellar consist of a single pellet, a masterpiece of plastic art. It is a miniature reproduction of the pear-shaped ball of the Scarabæus, a reproduction whose very smallness gives an added value to the polish of the surface and the beauty of its curves. Its larger diameter varies from half to three-quarters of an inch. It is the most elegant product of the dung-beetle's art.

But this perfection is of brief duration. Very soon the little "pear" becomes covered with gnarled excrescences, black and twisted, which disfigure it like so many warts. Part of the surface, which is otherwise intact, disappears under a shapeless mass. The origin of these knotted excrescences completely deceived me at first. I suspected some cryptogamic vegetation, some Spheriæcæa, for example, recognisable by its black, knotted, incrusted growth. It was the larva that showed me my mistake.

The larva is a maggot curved like a hook, carrying on its back an ample pouch or hunch, forming part of its alimentary canal. The reserve of excreta in this hunch enables it to seal accidental perforations of the shell of its lodging with an instantaneous jet of mortar. These sudden emissions, like little worm-casts, are also practised by the Scarabæus, but the latter rarely makes use of them.

The larvæ of the various dung-beetles utilise their alimentary residues in rough-casting their houses, which by their dimensions lend themselves to this method of disposal, while evading the necessity of opening temporary windows by which the ordure can be expelled. Whether for lack of sufficient room, or for other reasons which escape me, the larva of the Sisyphus, having employed a certain amount in the smoothing of the interior, ejects the rest of its digestive products from its dwelling.

Let us examine one of these "pears" when the inmate is already partly grown. Sooner or later we shall see a spot of moisture appear at some point on the surface; the wall softens, becomes thinner, and then, through the softened shell, a jet of dark green excreta rises and falls back upon itself in corkscrew convolutions. One excrescence the more has been formed; as it dries it becomes black.

What has occurred? The larva has opened a temporary breach in the wall of its shell; and through this orifice, in which a slight thickness of the outer glaze still remains, it has expelled the excess of mortar which it could not employ within. This practice of forming oubliettes in the shell of its prison does not endanger the grub, as they are immediately closed, and hermetically sealed by the base of the jet, which is compressed as by a stroke of a trowel. The stopper is so quickly put in place that the contents remain moist in spite of the frequent breaches made in the shell of the "pear." There is no danger of an influx of the dry outer air.

The Sisyphus seems to be aware of the peril which later on, in the dog-days, will threaten its "pear," small as it is, and so near the surface of the ground. It is extremely precocious. It labours in April and May when the air is mild. In the first fortnight of July, before the terrible dog-days have arrived, the members of its family break their shells and set forth in search of the heap of droppings which will furnish them with food and lodging during the fierce days of summer. Then come the short but pleasant days of autumn, the retreat underground and the winter torpor, the awakening of spring, and finally the cycle is closed by the festival of pellet-making.

One word more as to the fertility of the Sisyphus. My six couples under the wire-gauze cover furnished me with fifty-seven inhabited pellets. This gives an average of more than nine to each couple; a figure which the Scarabæus sacer is far from attaining. To what should we attribute this superior fertility? I can only see one cause: the fact that the male works as valiantly as the female. Family cares too great for the strength of one are not too heavy when there are two to support them.