Insect Adventures. Fabre Jean-Henri

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      I remove a number of Caddis-worms from their sheaths and put the sheaths in the water. Not one of them floats, neither those made of shells nor those of woody materials. The Worm also, when removed from its tube, is unable to float.

      This is how the Worm manages. When at rest, at the bottom of the pond, it fills the whole of the tube of its sheath. When it wishes to reach the top of the pond, it climbs up the reeds, dragging its house of sticks with it; then it sticks the front of its body out of the sheath, leaving a vacant space in the rear, like the vacuum in a pump when one draws out the piston. This promptly fills with air, enabling the Worm to float, sheath and all, just as the air in a life-preserver holds a person up in the water. The Caddis-worm does not need to cling to the grasses any longer. It can move about on the surface of the pond, in the glad sunlight.

      To be sure, it is not very talented as a boatman. But it can turn round, tack about and shift its place slightly by using the front part of its body, which is out of the tube, as a rudder and paddle; and that is all it wishes to do. When it has had enough of the sun, and thinks it time to return to the quiet of the mud-bed at the bottom, it draws itself back into its sheath, expelling the air, and at once begins to sink.

      We have our submarines—the Caddis-worms have theirs. They can come out of the water, they can dip down and even stop at mid-depth by releasing gradually the surplus air. And this apparatus, so perfectly balanced, so skillful, requires no knowledge on the part of its maker. It comes into being of itself, in accordance with the plans of the universal harmony of things.

CHAPTER III THE MASON-BEES

       Table of Contents

      At a school where I once taught, one subject in particular appealed to both master and pupils. This was open-air geometry, practical surveying. When May came, once every week we left the gloomy schoolroom for the fields. It was a regular holiday. We did our surveying on an untilled plain, covered with flowering thyme and rounded pebbles. There was room there for making every sort of triangle or polygon.

      Well, from the very first day, my attention was attracted by something suspicious. If I sent one of the boys to plant a stake, I would see him stop frequently on his way, bend down, stand up again, look about and stoop once more, neglecting his straight line and his signals. Another, who was told to pick up the arrows, would forget and take up a pebble instead; and a third, instead of measuring angles, would crumble a clod of earth between his fingers.

      Most of them were caught licking a bit of straw. The surveying suffered. What could the mystery be?

      I inquired; and everything was explained. The scholars had known for a long time what the master had not yet heard of, namely, that there was a big black Bee who made clay nests on the pebbles in the fields. These nests contained honey; and my surveyors used to open them and empty the cells with a straw. The honey, although rather strong-flavored, was most acceptable. I grew fond of it myself, and joined the nest-hunters, putting off the lesson until later. It was thus that I first made the acquaintance of the Mason-bee.

      The Bee herself is a magnificent insect, with dark-violet wings and a black-velvet dress. We have two kinds of Mason-bees in our district: this one, who builds by herself on walls or pebbles, and the Sicilian Mason-bee, who builds in colonies under sheds and roofs. Both use the same kind of material: hard clay, mixed with a little sand and kneaded into a paste with the Bee’s own saliva, forming, when dry, a sort of hard cement.

      Man’s masonry is formed of stones laid one above the other and cemented together with lime. The Mason-bee’s work can bear comparison with ours. Instead of stones, she uses big pieces of gravel. She chooses them carefully one by one, picks out the hardest bits, generally with corners, which, fitting one into the other, make a solid whole. She holds them together with layers of her mortar, sparingly applied. Thus the outside of her cell looks like a rough stone house; but the inside, which must be smooth in order not to hurt the Bee-baby’s tender skin, is covered with a coat of pure mortar. This inner whitewash, however, is not put on artistically, but in great splashes; and the grub takes care, after it has finished eating its honey, to make itself a cocoon and hang the walls of its room with silk.

      When the cell is finished, the Bee at once sets to work to provide food for it. The flowers round about, especially those of the yellow broom, which in May deck the pebbly borders of the mountain streams with gold, supply her with sugary liquid and pollen. She comes with her crop swollen with honey and her body yellowed underneath with pollen-dust. She dives headfirst into the cell; and for a few moments you see her jerk violently as she empties her crop of the honey-sirup. Afterwards, she comes out of the cell, only to go in again at once, but this time backwards. The Bee now brushes the lower side of her abdomen with her two hind-legs and rids herself of her load of pollen. Once more she comes out and once more goes in headfirst. It is a question of stirring the materials, with her jaws for a spoon, and making the whole into a smooth mixture. She does not do this after every journey; only once in a while, when she has gathered a good deal of food.

      When the cell is half full of food, she thinks there is enough. An egg must now be laid on top of the paste and the house must be closed. All this is done quickly. The cover is a lid of pure mortar, which the Bee builds by degrees, working from the outside to the center. Two days at most appeared to me to be enough for everything, provided that no bad weather—rain or merely clouds—came to interrupt the work. Then a second cell is built, with its back to the first and provisioned in the same manner. A third, a fourth, and so on follow, each supplied with honey and an egg and closed before the foundations of the next are laid.

      “The flowers which deck the mountain streams with gold supply her with sugary liquid and pollen.”

      When all the cells are finished, the Bee builds a thick cover over the group, to protect her grub-babies from damp, heat and cold. This cover is made of the usual mortar, but on this occasion with no small stones in it. The Bee applies it pellet by pellet, trowelful by trowelful, to the depth of about a third of an inch over the cluster of cells, which disappear entirely under the clay covering. When this is done, the nest has the shape of a rough dome, equal in size to half an orange. One would take it for a round lump of mud which had been thrown and half crushed against a stone and had then dried where it was. This outer covering dries as quickly as the cement we use in our houses; and the nest is soon almost as hard as a stone.

      Instead of building a brand-new nest on a hitherto unoccupied bowlder, the Mason-bee of the Walls is always glad to make use of old nests built the year before. These need only a little repair to put them in good condition. The Bee who has chosen one of these nests looks about to see what parts need repairing, tears off the strips of cocoon hanging from the walls, removes the fragments of clay that fell from the ceiling when the young Bee of the preceding year bored her way through it, gives a coat of mortar to parts that need it, mends the opening a little, and that is all. She then goes about storing honey and laying her egg, as she would in a new cell. When all the cells, one after the other, are thus furnished, the Bee puts a few touches on the outer dome of cement, if it needs them; and she is through.

      From one and the same nest there come out several inhabitants, brothers and sisters, the males with a bright brick-red fleece, and the female of a splendid velvety black, with dark-violet wings. They are all the children of the Bee who built or repaired СКАЧАТЬ