The evidence of the Leaf-cutters proves that a certain latitude is
left to the insect in its choice of materials for the nest; and this is
confirmed by the testimony of the Anthidia, the cotton-manufacturers.
My district possesses five: A. Florentinum, LATR., A. diadema, LATR., A.
manicatum, LATR., A. cingulatum, LATR., A. scapulare, LATR. None of them
creates the refuge in which the cotton goods are manufactured. Like the
Osmiae and the Leaf-cutters, they are homeless vagrants, adopting,
each to her own taste, such shelter as the work of others affords. The
Scapular Anthidium is loyal to the dry bramble, deprived of its pith and
turned into a hollow tube by the industry of various mining Bees, among
which figure, in the front rank, the Ceratinae, dwarf rivals of the
Xylocopa, or Carpenter-bee, that mighty driller of rotten wood.
The spacious galleries of the Masked Anthophora suit the Florentine
Anthidium, the foremost member of the genus so far as size is concerned.
The Diadem Anthidium considers that she has done very well if she
inherits the vestibule of the Hairy-footed Anthophora, or even the
ordinary burrow of the Earth-worm. Failing anything better, she may
establish herself in the dilapidated dome of the Mason-bee of the
Pebbles. The Manicate Anthidium shares her tastes. I have surprised the
Girdled Anthidium cohabiting with a Bembex-wasp. The two occupants of
the cave dug in the sand, the owner and the stranger, were living in
peace, both intent upon their business. Her usual habitation is some
hole or other in the crevices of a ruined wall. To these refuges, the
work of others, we can add the stumps of reeds, which are as popular
with the various cotton-gatherers as with the Osmiae; and, after we have
mentioned a few most unexpected retreats, such as the sheath provided
by a hollow brick or the labyrinth furnished by the lock of a gate, we
shall have almost exhausted the list of domiciles.
Like the Osmiae and the Leaf-cutters, the Anthidium shows an urgent need
of a ready-made home. She never houses herself at her own expense. Can
we discover the reason? Let us first consult a few hard workers who are
artificers of their own dwellings. The Anthophora digs corridors and
cells in the road-side banks hardened by the sun; she does not erect,
she excavates; she does not build, she clears. Toiling away with her
mandibles, atom by atom, she manages to contrive the passages and
chambers necessary for her eggs; and a huge business it is. She has, in
addition, to polish and glaze the rough sides of her tunnels. What would
happen if, after obtaining a home by dint of long-continued toil,
she had next to line it with wadding, to gather the fibrous down from
cottony plants and to felt it into bags suitable for the honey-paste?
The hard-working Bee would not be equal to producing all these
refinements. Her mining calls for too great an expenditure of time and
strength to leave her the leisure for luxurious furnishing. Chambers and
corridors, therefore, will remain bare.
The Carpenter-bee gives us the same answer. When with her joiner's
wimble she has patiently bored the beam to a depth of nine inches, would
she be able to cut out and place in position the thousand and one pieces
which the Silky Leaf-cutter employs for her nest? Time would fail her,
even as it would fail a Megachile who, lacking the Capricorn's chamber,
had herself to dig a home in the trunk of the oak. Therefore the
Carpenter-bee, after the tedious work of boring, gets the installation
done in the most summary fashion, simply running up a sawdust partition.
The two things, the laborious business of obtaining a lodging and the
artistic work of furnishing, seem unable to go together. With the
insect as with man, he who builds the house does not furnish it, he who
furnishes it does not build it. To each his share, because of lack of
time. Division of labour, the mother of the arts, makes the workman
excel in his department; one man for the whole work would mean
stagnation, the worker never getting beyond his first crude attempts.
Animal industry is a little like our own: it does not attain its
perfection save with the aid of obscure toilers, who, without knowing
it, prepare the final masterpiece. I see no other reason for this
need of a gratuitous lodging for the Megachile's leafy basket or the
Anthidia's cotton purses. In the case of other artists who handle
delicate things that require protection, I do not hesitate to assume
the existence of a ready-made home. Thus Reaumur tells us of the
Upholsterer-bee, Anthocopa papaveris, who fashions her cells with
poppy-petals. I do not know the flower-cutter, I have never seen her;
but her art tells me plainly enough that she must establish herself in
some gallery wrought by others, as, for instance, in an Earth-worm's
burrow.
We have but to see the nest of a Cotton-bee to convince ourselves that
its builder cannot at the same time be an indefatigable navvy. When and
newly-felted and not yet made sticky with honey, the wadded purse is
by far the most elegant known specimen of entomological nest-building,
especially where the cotton is of a brilliant white, as is frequently
the case in the manufacturers of the Girdled Anthidium. No bird's-nest,
however deserving of our admiration, can vie in fineness of flock, in
gracefulness of form, in delicacy of felting with this wonderful bag,
which our fingers, even with the aid of tools, could hardly imitate, for
all their dexterity. I abandon the attempt to understand how, with its
little bales of cotton brought up one by one, the insect, no otherwise
gifted than the kneaders of mud and the makers of leafy baskets, manages
to felt what it has collected into a homogeneous whole and then to work
the product into a thimble-shaped wallet. Its tools as a master-fuller
are its legs and its mandibles, which are just like those possessed by
the mortar-kneaders and Leaf-cutters; and yet, despite this similarity
of outfit, what a vast difference in the results obtained!
To see the Cotton-bees' talents in action seems an undertaking fraught
with innumerable difficulties: things happen at a depth inaccessible to
the eye; and to persuade the insect to work in the open does not lie
in our power. One resource remained and I did not fail to turn to
it, though hitherto I have been wholly unsuccessful. Three species,
Anthidium diadema, A. manicatum and A. florentinum--the first-named in
particular--show themselves quite ready to take up their abode in my
reed-apparatus. All that I had to do was to replace the reeds by glass
tubes, which would allow me to watch the work without disturbing the
insect. This stratagem had answered perfectly with the Three-horned
Osmia and Latreille's Osmia, whose little housekeeping-secrets I had
learnt thanks to the transparent dwelling-house. Why should it not
answer for its Cotton-bees and, in the same way, with the Leaf-cutters?
I almost counted on success. Events betrayed my confidence. For
four years I supplied my hives with glass tubes and not once did the
Cotton-weavers or the Leaf-cutters condescend to take up their quarters
in the crystal palaces. They always preferred the hovel provided by the
reed. Shall I persuade them one day? I do not abandon all hope.
Meanwhile, let me describe the little that I saw. More or less stocked
with cells, the reed is at last closed, right at the orifice, with
a thick plug of cotton, usually coarser than the wadding of the
honey-satchels. It is the equivalent of the Three-horned Osmia's
barricade of mud, of the leaf-putty of Latreille's Osmia, of the
Megachiles' barrier of leaves cut into disks. All these free tenants are
careful to shut tight the door of the dwelling, of which they have often
utilized only a portion. To watch the building of this barricade, which
is almost external work, demands but a little patience in waiting for
the favourable moment.
The Anthidium arrives at last, carrying the bale of cotton for the
plugging. With her fore-legs she tears it apart and spreads it out; with
her mandibles, which go in closed and come out open, she loosens the
hard lumps of flock; with her forehead she presses each new layer upon
the one below. And that is all. The insect flies off, returns the richer
by another bale and repeats the performance until the cotton barrier
reaches the level of the opening. We have here, remember, a rough task,
in no way to be compared with the delicate manufacturer of the bags;
nevertheless, it may perhaps tell us something of the general procedure
of the finer work. The legs do the carding, the mandibles the dividing,
the forehead the pressing; and the play of these implements produces the
wonderful cushioned wallet. That is the mechanism in the lump; but what
of the artistry?
Let us leave the unknown for facts within the scope of observation. I
will question the Diadem Anthidium in particular, a frequent inmate
of my reeds. I open a reed-stump about two decimetres long by twelve
millimetres in diameter. (About seven and three-quarter inches by
half an inch.--Translator's Note.) The end is occupied by a column of
cotton-wool comprising ten cells, without any demarcation between
them on the outside, so that their whole forms a continuous cylinder.
Moreover, thanks to a close felting, the different compartments are
soldered together, so much so that, when pulled by the end, the cotton
edifice does not break into sections, but comes out all in one piece.
One would take it for a single cylinder, whereas in reality the work
is composed of a series of chambers, each of which has been constructed
separately, independently of the one before, except perhaps at the base.
For this reason, short of ripping up the soft dwelling, still full of
honey, it is impossible to ascertain the number of storeys; we must
wait until the cocoons are woven. Then our fingers can tell the cells by
counting the knots that resist pressure under the cover of wadding. This
general structure is easily explained. A cotton bag is made, with the
sheath of the reed as a mould. If this guiding sheath were lacking, the
thimble shape would be obtained all the same, with no less elegance,
as is proved by the Girdled Anthidium, who makes her nest in some
hiding-place or other in the walls or the ground. When the purse is
finished, the provisions come and the egg, followed by the closing of
the cell. We do not here find the geometrical lid of the Leaf-cutters,
the pile of disks tight-set in the mouth of the jar. The bag is closed
with a cotton sheet whose edges are soldered by a felting-process to the
edges of the opening. The soldering is so well done that the honey-pouch
and its cover form an indivisible whole. Immediately above it, the
second cell is constructed, having its own base. At the beginning of
this work, the insect takes care to join the two storeys by felting the
ceiling of the first to the floor of the second. Thus continued to the
end, the work, with its inner solderings, becomes an unbroken cylinder,
in which the beauties of the separate wallets disappear from view. In
very much the same fashion, but with less adhesion among the different
cells, do the Leaf-cutters act when stacking their jars in a column
without any external division into storeys.
Let us return to the reed-stump which gives us these details. Beyond the
cotton-wool cylinder wherein ten cocoons are lodged in a row comes
an empty space of half a decimetre or more. (About two
inches.--Translator's Note.) The Osmiae and the Leaf-cutters are also
accustomed to leave these long, deserted vestibules. The nest ends, at
the orifice of the reed, with a strong plug of flock coarser and less
white than that of the cells. This use of closing-materials which are
less delicate in texture but of greater resisting-power, while not an
invariable characteristic, occurs frequently enough to make us suspect
that the insect knows how to distinguish what is best suited now to the
snug sleeping-berth of the larvae, anon to the defensive barricade of
the home. Sometimes the choice is an exceedingly judicious one, as is
shown by the nest of the Diadem Anthidium. Time after time, whereas the
cells were composed of the finest grade of white cotton, gathered from
Centaurea solsticialis, or St. Barnaby's thistle, the barrier at the
entrance, differing from the rest of the work in its yellow colouring,
was a heap of close-set bristles supplied by the scallop-leaved mullein.
The two functions of the wadding are here plainly marked. The delicate
skin of the larvae needs a well-padded cradle; and the mother collects
the softest materials that the cottony plants provide. Rivalling the
bird, which furnishes the inside of the nest with wool and strengthens
the outside with sticks, she reserves for the grubs' mattress the finest
down, so hard to find and collected with such patience. But, when it
becomes a matter of shutting the door against the foe, then the entrance
bristles with forbidding caltrops, with stiff, prickly hairs.
This ingenious system of defence is not the only one known to the
Anthidia. More distrustful still, the Manicate Anthidium leaves no space
in the front part of the reed. Immediately after the column of cells,
she heaps up, in the uninhabited vestibule, a conglomeration of rubbish,
whatever chance may offer in the neighbourhood of the nest: little
pieces of gravel, bits of earth, grains of sawdust, particles of mortar,
cypress-catkins, broken leaves, dry Snail-droppings and any other
material that comes her way. The pile, a real barricade this time,
blocks the reed completely to the end, except about two centimetres
(About three-quarters of an inch.--Translator's Note.) left for the
final cotton plug. Certainly no foe will break in through the double
rampart; but he will make an insidious attack from the rear.
The Leucopsis will come and, with her long probe, thanks to some
imperceptible fissure in the tube, will insert her dread eggs and
destroy every single inhabitant of the fortress. Thus are the Manicate
Anthidium's anxious precautions outwitted.
If we had not already seen the same thing with the Leaf-cutters, this
would be the place to enlarge upon the useless tasks undertaken by the
insect when, with its ovaries apparently depleted, it goes on spending
its strength with no maternal object in view and for the sole pleasure
of work. I have come across several reeds stopped up with flock though
containing nothing at all, or else furnished with one, two or three
cells devoid of provisions or eggs. The ever-imperious instinct
for gathering cotton and felting it into purses and heaping it into
barricades persists, fruitlessly, until life fails. The Lizard's tail
wriggles, curls and uncurls after it is detached from the animal's body.
In these reflex movements, I seem to see not an explanation, certainly,
but a rough image of the industrious persistency of the insect, still
toiling away at its business, even when there is nothing useful left to
do. This worker knows no rest but death.
I have said enough about the dwelling of the Diadem Anthidium; let us
look at the inhabitant and her provisions. The honey is pale-yellow,
homogeneous and of a semifluid consistency, which prevents it from
trickling through the porous cotton bag. The egg floats on the surface
of the heap, with the end containing the head dipped into the paste. To
follow the larva through its progressive stages is not without interest,
especially on account of the cocoon, which is one of the most singular
that I know. With this object in view, I prepare a few cells that lend
themselves to observation. I take a pair of scissors, slice a piece off
the side of the cotton-wool purse, so as to lay bare both the victuals
and the consumer, and place the ripped cell in a short glass tube.
During the first few days, nothing striking happens. The little grub,
with its head still plunged in the honey, slakes its thirst with long
draughts and waxes fat. A moment comes...But let us go back a little
farther, before broaching this question of sanitation.
Every grub, of whatever kind, fed on provisions collected by the mother
and placed in a narrow cell is subject to conditions of health unknown
to the roving grub that goes where it likes and feeds itself on what it
can pick up. The first, the recluse, is no more able than the second,
the gadabout, to solve the problem of a food which can be entirely
assimilated, without leaving an unclean residue. The second gives no
thought to these sordid matters: any place suits it for getting rid
of that difficulty. But what will the other do with its waste matter,
cooped up as it is in a tiny cell stuffed full of provisions? A most
unpleasant mixture seems inevitable. Picture the honey-eating grub
floating on liquid provisions and fouling them at intervals with its
excretions! The least movement of the hinder-part would cause the
whole to amalgamate; and what a broth that would make for the delicate
nursling! No, it cannot be; those dainty epicures must have some method
of escaping these horrors.
They all have, in fact, and most original methods at that. Some take
the bull by the horns, so to speak, and, in order not to soil things,
refrain from uncleanliness until the end of the meal: they keep the
dropping-trap closed as long as the victuals are unfinished. This is
a radical scheme, but not in every one's power, it appears. It is
the course adopted, for instance, by the Sphex-wasps and the
Anthophora-bees, who, when the whole of the food is consumed, expel at
one shot the residues amassed in the intestines since the commencement
of the repast.
Others, the Osmiae in particular, accept a compromise and begin to
relieve the digestive tract when a suitable space has been made in
the cell through the gradual disappearance of the victuals. Others
again--more hurried these--find means of obeying the common law pretty
early by engaging in stercoral manufactures. By a stroke of genius, they
make the unpleasant obstruction into building-bricks. We already know
the art of the Lily-beetle (Crioceris merdigera. Fabre's essay on this
insect has not yet been translated into English; but readers interested
in the matter will find a full description in "An Introduction to
Entomology," by William Kirby, Rector of Barham, and William Spence:
letter 21.--Translator's Note.), who, with her soft excrement, makes
herself a coat wherein to keep cool in spite of the sun. It is a very
crude and revolting art, disgusting to the eye. The Diadem Anthidium
belongs to another school. With her droppings she fashions masterpieces
of marquetry and mosaic, which wholly conceal their base origin from the
onlooker. Let us watch her labours through the windows of my tubes.
When the portion of food is nearly half consumed, there begins and goes
on to the end a frequent defecation of yellowish droppings, each hardly
the size of a pin's head. As these are ejected, the grub pushes them
back to the circumference of the cell with a movement of its hinder-part
and keeps them there by means of a few threads of silk. The work of
the spinnerets, therefore, which is deferred in the others until the
provisions are finished, starts earlier here and alternates with the
feeding. In this way, the excretions are kept at a distance, away from
the honey and without any danger of getting mixed with it. They end by
becoming so numerous as to form an almost continuous screen around the
larva. This excremental awning, made half of silk and half of droppings,
is the rough draft of the cocoon, or rather a sort of scaffolding on
which the stones are deposited until they are definitely placed in
position. Pending the piecing together of the mosaic, the scaffolding
keeps the victuals free from all contamination.
To get rid of what cannot be flung outside, by hanging it on the
ceiling, is not bad to begin with; but to use it for making a work of
art is better still. The honey has disappeared. Now commences the final
weaving of the cocoon. The grub surrounds itself with a wall of silk,
first pure white, then tinted reddish-brown by means of an adhesive
varnish. Through its loose-meshed stuff, it seizes one by one the
droppings hanging from the scaffold and inlays them firmly in the
tissue. The same mode of work is employed by the Bembex-, Stizus-and
Tachytes-wasps and other inlayers, who strengthen the inadequate woof
of their cocoons with grains of sand; only, in their cotton-wool purses,
the Anthidium's grubs substitute for the mineral particles the only
solid materials at their disposal. For them, excrement takes the place
of pebbles.
And the work goes none the worse for it. On the contrary: when the
cocoon is finished, any one who had not witnessed the process of
manufacture would be greatly puzzled to state the nature of the
workmanship. The colouring and the elegant regularity of the outer
wrapper of the cocoon suggest some kind of basket-work made with tiny
bits of bamboo, or a marquetry of exotic granules. I too let myself be
caught by it in my early days and wondered in vain what the hermit of
the cotton wallet had used to inlay her nymphal dwelling so prettily
withal. To-day, when the secret is known to me, I admire the ingenuity
of the insect capable of obtaining the useful and the beautiful out of
the basest materials.
The cocoon has another surprise in store for us. The end containing the
head finishes with a short conical nipple, an apex, pierced by a narrow
shaft that establishes a communication between the inside and the
out. This architectural feature is common to all the Anthidia, to the
resin-workers who will occupy our attention presently, as well as to the
cotton-workers. It is found nowhere outside the Anthidium group.
What is the use of this point which the larva leaves bare instead of
inlaying it like the rest of the shell? What is the use of that hole,
left quite open or, at most, closed at the bottom with a feeble grating
of silk? The insect appears to attach great importance to it, from what
I see. In point of fact, I watch the careful work of the apex. The grub,
whose movements the hole enables me to follow, patiently perfects the
lower end of the conical channel, polishes it and gives it an exactly
circular shape; from time to time, it inserts into the passage its
two closed mandibles, whose points project a little way outside; then,
opening them to a definite radius, like a pair of compasses, it widens
the aperture and makes it regular.
I imagine, without venturing, however, to make a categorical statement,
that the perforated apex is a chimney to admit the air required for
breathing. Every pupa breathes in its shell, however compact this may
be, even as the unhatched bird breathes inside the egg. The thousands
of pores with which the shell is pierced allow the inside moisture to
evaporate and the outer air to penetrate as and when needed. The stony
caskets of the Bembex- and Stizus-wasps are endowed, notwithstanding
their hardness, with similar means of exchange between the vitiated and
the pure atmosphere. Can the shells of the Anthidia be air-proof, owing
to some modification that escapes me? In any case, this impermeability
cannot be attributed to the excremental mosaic, which the cocoons of the
resin-working Anthidia do not possess, though endowed with an apex of
the very best.
Shall we find an answer to the question in the varnish with which the
silken fabric is impregnated? I hesitate to say yes and I hesitate to
say no, for a host of cocoons are coated with a similar lacquer though
deprived of communication with the outside air. All said, without being
able at present to account for its necessity, I admit that the apex of
the Anthidia is a breathing-aperture. I bequeath to the future the task
of telling us for what reasons the collectors of both cotton and resin
leave a large pore in their shells, whereas all the other weavers close
theirs completely.
After these biological curiosities, it remains for me to discuss the
principal subject of this chapter: the botanical origin of the materials
of the nest. By watching the insect when busy at its harvesting, or else
by examining its manufactured flock under the microscope, I was able to
learn, not without a great expenditure of time and patience, that the
different Anthidia of my neighbourhood have recourse without distinction
to any cottony plant. Most of the wadding is supplied by the Compositae,
particularly the following: Centaurea solsticialis, or St. Barnaby's
thistle; C. paniculata, or panicled centaury; Echinops ritro, or
small globe-thistle; Onopordon illyricum, or Illyrian cotton-thistle;
Helichrysum staechas, or wild everlasting; Filago germanica, or common
cotton-rose. Next come the Labiatae: Marrubium vulgare, or common white
horehound; Ballota fetida, or stinking horehound; Calamintha nepeta,
or lesser calamint; Salvia aethiopis, or woolly sage. Lastly, the
Solanaceae: Verbascum thapsus, or shepherd's club; V. sinuatum, or
scollop-leaved mullein.
The Cotton-bees' flora, we see, incomplete as it is in my notes,
embraces plants of very different aspect. There is no resemblance in
appearance between the proud candelabrum of the cotton-thistle, with its
red tufts, and the humble stalk of the globe-thistle, with its sky-blue
capitula; between the plentiful leaves of the mullein and the scanty
foliage of the St. Barnaby's thistle; between the rich silvery fleece
of the woolly sage and the short hairs of the everlasting. With the
Anthidium, these clumsy botanical characteristics do not count; one
thing alone guides her: the presence of cotton. Provided that the plant
be more or less well-covered with soft wadding, the rest is immaterial
to her.
Another condition, however, has to be fulfilled, apart from the fineness
of the cotton-wool. The plant, to be worth shearing, must be dead and
dry. I have never seen the harvesting done on fresh plants. In this
way, the Bee avoids mildew, which would make its appearance in a mass of
hairs still filled with sap.
Faithful to the plant recognized as yielding good results, the Anthidium
arrives and resumes her gleaning on the edges of the parts denuded by
earlier harvests. Her mandibles scrape away and pass the tiny fluffs,
one by one, to the hind-legs, which hold the pellet pressed against the
chest, mix with it the rapidly-increasing store of down and make the
whole into a little ball. When this is the size of a pea, it goes back
into the mandibles; and the insect flies off, with its bale of cotton
in its mouth. If we have the patience to wait, we shall see it return to
the same point, at intervals of a few minutes, so long as the bag is not
made. The foraging for provisions will suspend the collecting of cotton;
then, next day or the day after, the scraping will be resumed on the
same stalk, on the same leaf, if the fleece be not exhausted. The owner
of a rich crop appears to keep to it until the closing-plug calls for
coarser materials; and even then this plug is often manufactured with
the same fine flock as the cells.
After ascertaining the diversity of cotton-fields among our native
plants, I naturally had to enquire whether the Cotton-bee would also
put up with exotic plants, unknown to her race; whether the insect would
show any hesitation in the presence of woolly plants offered for the
first time to the rakes of her mandibles. The common clary and the
Babylonian centaury, with which I have stocked the harmas, shall be the
harvest-fields; the reaper shall be the Diadem Anthidium, the inmate of
my reeds.
The common clary, or toute-bonne, forms part, I know, of our French
flora to-day; but it is an acclimatized foreigner. They say that a
gallant crusader, returning from Palestine with his share of glory and
bruises, brought back the toute-bonne from the Levant to help him cure
his rheumatism and dress his wounds. From the lordly manor, the plant
propagated itself in all directions, while remaining faithful to the
walls under whose shelter the noble dames of yore used to grow it for
their unguents. To this day, feudal ruins are its favourite resorts.
Crusaders and manors disappeared; the plant remained. In this case, the
origin of the clary, whether historical or legendary, is of secondary
importance. Even if it were of spontaneous growth in certain parts
of France, the toute-bonne is undoubtedly a stranger in the Vaucluse
district. Only once in the course of my long botanizing-expeditions
across the department have I come upon this plant. It was at Caromb, in
some ruins, nearly thirty years ago. I took a cutting of it; and since
then the crusaders' sage has accompanied me on all my peregrinations.
My present hermitage possesses several tufts of it: but, outside the
enclosure, except at the foot of the walls, it would be impossible to
find one. We have, therefore, a plant that is new to the country for
many miles around, a cotton-field which the Serignan Cotton-bees had
never utilized before I came and sowed it.
Nor had they ever made use of the Babylonian centaury, which I was the
first to introduce in order to cover my ungrateful stony soil with
some little vegetation. They had never seen anything like the colossal
centaury imported from the region of the Euphrates. Nothing in the local
flora, not even the cotton-thistle, had prepared them for this stalk
as thick as a child's wrist, crowned at a height of nine feet with a
multitude of yellow balls, nor for those great leaves spreading over the
ground in an enormous rosette. What will they do in the presence of such
a find? They will take possession of it with no more hesitation than if
it were the humble St. Barnaby's thistle, the usual purveyor.
In fact, I place a few stalks of clary and Babylonian centaury,
duly dried, near the reed-hives. The Diadem Anthidium is not long in
discovering the rich harvest. Straight away the wool is recognized as
being of excellent quality, so much so that, during the three or four
weeks of nest-building, I can daily witness the gleaning, now on the
clary, now on the centaury. Nevertheless the Babylonian plant appears to
be preferred, no doubt because of its whiter, finer and more plentiful
down. I keep a watchful eye on the scraping of the mandibles and the
work of the legs as they prepare the pellet; and I see nothing
that differs from the operations of the insect when gleaning on
the globe-thistle and the St. Barnaby's thistle. The plant from the
Euphrates and the plant from Palestine are treated like those of the
district.
Thus we find what the Leaf-cutters taught us proved, in another way,
by the cotton-gatherers. In the local flora, the insect has no precise
domain; it reaps its harvest readily now from one species, now from
another, provided that it find the materials for its manufactures. The
exotic plant is accepted quite as easily as that of indigenous growth.
Lastly, the change from one plant to another, from the common to the
rare, from the habitual to the exceptional, from the known to the
unknown, is made suddenly, without gradual initiations. There is no
novitiate, no training by habit in the choice of the materials for
the nest. The insect's industry, variable in its details by sudden,
individual and non-transmissible innovations, gives the lie to the two
great factors of evolution: time and heredity.