Social Life in the Insect World

by Jean-Henri Fabre

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.