Homes Without Hands: Being a Description of the Habitations of Animals, Classed According to Their Principle of Construction - Page 27

While some of the ants were engaged in this task, which must be considered analogous to brickmaking as practiced by mankind, others were scooping out shallow hollows in the clay floor, the little ridges that were left standing being the foundation of the new walls. On these were dabbed the earthen pellets, and adjusted by means of the mandibles or by pressure of the fore feet, thus receiving compactness and uniformity. The most difficult part of such a task is the formation of the ceiling, but the ants do not appear to be at all embarrassed by so formidable an undertaking, but can lay ceilings of two inches in diameter with perfect certainty. The method of constructing the ceiling is by moulding the clay pellets into each angle of the chamber and also to the top of the pillars. As fast as one row of pellets becomes dry, a second is added; and the insects perform this delicate duty with such accuracy, that although so many centres are employed, the parts always coincide in the proper spots. The peculiar kneading and biting to which the clay pellets are subjected makes them exceedingly tenacious, so that they adhere strongly on the slightest contact.

When once these walls are completed, they are of very great strength, and are only the more consolidated by rain and heat. Before their completion, however, they do not appear to endure the extreme either of heat or moisture, and are taken to pieces by the little architects if a drought should check the supply of that moisture, without which the work can not be properly compacted.

Mr. Rennie, who followed up the observations of Huber, makes the following remarks on the nest of the ant:—“On digging cautiously into a natural ant-hill, established upon the edge of a garden walk, we were enabled to obtain a pretty complete view of the interior structure. There were two stories, composed of large chambers, irregularly oval, communicating with each other by arched galleries, the walls of all which were as smooth as if they had been passed over by a plasterer’s trowel. The floors of the chambers, we remarked, were by no means either horizontal or level, but all more or less sloped, and exhibiting in each chamber at least two slight depressions of an irregular shape. We left the under story of this nest untouched, with the notion that the ants might repair the upper galleries, of which we had made a vertical section; but instead of doing so, they migrated during the day to a large crack, formed by the dryness of the weather, about a yard from their old nest.”

This description is accompanied by a sketch of a portion of the dwelling. Five chambers are shown, two large and three small, communicating with the gallery by very short corridors.

It is a noteworthy fact, that the ant will always avail itself of any accidental circumstances that may assist it in building. For example, one of these industrious little beings has been observed to take advantage of some straws that happened to cross one another, and to convert them into beams, wherewith the ceiling

could be supported. It began the work by depositing the little clay pellets in the angles formed by the straws, and then laid several rows of the pellets along the sides of each straw. The ceiling rapidly grew under the jaws and feet of the ant, and on account of the extemporized beams, was necessarily of much greater strength than those which were constructed in the usual manner.

The common YELLOW Ant (Formica flava), so abundant in marshes and gardens, is also a good burrower, though its habitation is not so large or so elaborate as that of the Brown Ant. This species is very fond of making its subterranean houses under stones or similar substances, and I have found hundreds of the nests under flat stone tiles that had once been employed in edging the walks of a large kitchen-garden, and had been pressed aside or sunk flat upon the earth. It is a curiously sociable species, for it is often found occupying one side of a little hillock, while another species of ant, Myrmica scabrinodis, has possession of the other. This latter species is sometimes extremely abundant; and it is a rather remarkable fact, that some of our rarest British beetles are only to be found in the nests of the ants.

As is well known, the ants do not retain their wings for any lengthened period, and after these members have served the purpose for which they were intended, they are broken off by the insect by means of a transverse seam near the base. There are, however, many of the permanently winged hymenoptera which possess very great powers of burrowing, and are able to excavate soil so hard that a knife can scarcely make its way through the solidly impacted mass of earth and stones.

The mining bees, which belong to the genus Andrena, are admirable burrowers, and in spite of their small size, drive their little tunnels into the earth with astonishing ease. I once came on a whole colony of the Andrena, in a peculiarly hard and stony path near Dieppe. The ground was full of little holes, from which the bees were continually issuing, and into which others were as continually passing; their bodies yellow with the pollen of the flowers which they had been rifling, and which was intended to serve as a provision for the future brood.

An ordinary pocket-knife could make no impression on the ground, mixed as it was with stones, trodden by daily traffic, and baked by the heat of summer, into a mass nearly as hard as brick, harder perhaps than the bricks that are employed for modern houses. I was obliged, therefore, to return to my room and fetch a great, rude, thick-bladed clasp-knife that was reserved for rough work, and with much labor succeeded in tracing several of the burrows. They were sunk, on an average, about eight inches into the ground, and near the end they took a sudden turn, and were ended by a rounded chamber, in which was almost invariably a ball of pollen about as large as a pea. No larva was found in any of the burrows. The whole of the labor falls upon the female, the fore legs of the male being unable to dig, and the hind legs unable to carry the pollen.

The genus Andrena is of enormous extent, for in 1855, not less than sixty-eight acknowledged species had been discovered in England, and the number is probably increased after a space of nearly ten years.

One of the most interesting members of this family is the pretty insect known by the name of Eucera longicornis, and believed to be the only British representative of its genus. The name longicornis, or long-horned, is derived from the very long antennæ of the male, which is also remarkable for a notch on the first joint of the fore legs. The use of this notch we shall presently see. Like the bees which have just been mentioned, the Eucera digs a rather deep burrow, but prefers a clay soil. The extremity of the burrow is widened into an oval cell, the walls of which are beaten and pressed by the insect until they are quite hard. The reason for this precaution is, that the cell is stored with a mixture of honey and pollen, which is of a semi-fluid consistency, and would be absorbed by the earth if the walls of the cell were not “puddled,” as engineers call the operation.

Within the cell is placed the egg, and in due time the larva is hatched, and feeds on the soft sweet mixture with which it is surrounded. It then changes into the pupal condition, and is remarkable for being enveloped in a very thin pellicle, something like the slough of a snake. Even the antennæ are enveloped separately in the pellicle, and the male would find great difficulty in divesting itself from the membrane, were it not for the notch in the fore legs. As soon, however, as it is partially free, the insect bends down its head, lodges successively each antenna in the notch, closes the joint upon it, and then, by drawing the antennæ through the notch, strips off the pellicle with perfect ease.

Among these insects, the females are treated much as the wives of savages are treated. All the work falls to their lot, and the males do nothing but amuse themselves, circling about the nests in graceful undulations, while the females are hard at work, digging the burrows and fetching home the food. Still, there is no doubt but that this disparity is only in appearance, and that the one sex feels as much enjoyment in following the instinct which teaches her to dig, as does the other in following the instinct which teaches him to fly about.

At the right-hand side of the illustration on page 148 may be seen a figure of a remarkable burrowing bee, called Scolia flavifrons, a native of Europe, but not as yet proved to be British. In common with other fossorial bees, this insect is carnivorous in its larval state, and is supplied by its mother with the creatures on which it feeds.

Some insects feed upon larvæ, others upon full-grown insects. Some eat beetles, some devour bees, some prefer spiders, and others flies, while a very great number of species are caterpillar-eaters, and are in consequence extremely useful to the gardener and farmer. This particular insect has a curious predilection, and stocks its nest with the grub or larva of a beetle, belonging to the genus Oryctes. At the bottom of the cell may be seen certain grubs, the smaller of which is the larva of the Scolia, and the larger that of the beetle. As may be seen from the illustration, the grub of the beetle is very much larger than that of the creature which feeds upon it. The species which is here represented is a large and remarkably striking one, the four conspicuous spots at once distinguishing it from any other insect. In the middle of the illustration another example of a bee-burrower is given, in order to show the manner in which the insect takes its prey into the nest. The technical name of this species is Ampulex compressa, and its nest is stocked with cockroaches, one of which is being dragged into the hole, wherein it will be shortly eaten by the inhabitant.

As space is valuable, I will merely give the names of our most conspicuous burrowing bees, together with brief notice of their habits.

All the species belonging to the genus Pompilus are burrowers, and stock their nests with spiders. Sandy soils are favored spots with these bees, some species preferring the dry, hard sandbanks, while others choose soft and loamy sand for the site of their habitation. The Sand Wasps, belonging to the genus Ammophila, are always mighty burrowers, and set about their task with a fiery zeal that never fails to excite the admiration of the spectator, their antennæ quivering and their wings flirting with excitement. When the burrow is completed, the mother insect flies off in search of a caterpillar or spider, according to the species, and conveys it to the bottom of the tunnel, where a small chamber is excavated.

She always enters the burrow backward, grasping her prey in her jaws and dragging it after her. It is so large that she can scarcely force it along the tunnel, and were it not for the comparatively wide chamber, she would not be able to make her way out again. When she has fairly lodged it in the chamber, she creeps round it, deposits an egg upon it, and crawls out again, taking care to stop up the entrance with some small pebbles. She then flies away in search of a fresh victim, and after some four or five caterpillars have been placed in the nest, she closes the entrance carefully, flies off and dies, the great duty of her life being then at an end.

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