INSTINCT AND DISCERNMENT
The Pelopæus gives us a very poor idea of her intellect when she
plasters the spot in the wall where the nest which I have removed used
to stand, when she persists in cramming her cell with Spiders for the
benefit of an egg no longer there and when she dutifully closes a cell
which my tweezers, extracting both germ and provisions, have left
empty. The Mason-bees, the caterpillar of the Great Peacock Moth and
many others, when subjected to similar tests, are guilty of the same
illogical behaviour: they continue, in the normal order, their series
of industrious actions, though an accident has now rendered these
useless. Just like mill-stones, which do not cease revolving though
there be no corn left to grind, let them once be given the compelling
power and they will continue to perform their task despite its
futility. Are they then machines? Far be it from me to think anything
so foolish.
It is impossible to make definite progress on the shifting sands of
contradictory facts: each step in our interpretation may find us
embogged. And yet these facts speak so loudly that I do not hesitate to
translate their evidence as I understand it. In insect mentality, we
have to distinguish two very different domains. One of these is
instinct properly so called, the unconscious impulse that presides over
the most wonderful part of what the creature achieves with its
industry. Where experience and imitation are of absolutely no avail,
instinct lays down its inflexible law. It is instinct and instinct
alone that makes the mother build for a family which she will never
see; that counsels the storing of provisions for the unknown offspring;
that directs the sting towards the nerve-centres of the prey and
skilfully paralyses it, so that the game may keep good; that
instigates, in fine, a host of actions wherein shrewd reason and
consummate science would have their part, were the creature acting
through discernment.
This faculty is perfect of its kind from the outset; otherwise the
insect would have no posterity. Time adds nothing to it and takes
nothing from it. Such as it was for a definite species, such it is
to-day and such it will remain, perhaps the most settled zoological
characteristic of them all. It is not free nor conscious in its
practice, any more than is the faculty of the stomach for digestion or
that of the heart for pulsation. The phases of its operations are
predetermined, necessarily entailed one by another; they suggest a
system of clockwork wherein one wheel set in motion brings about the
movement of the next. This is the mechanical side of the insect, the
fatum, the only thing that is able to explain the monstrous
illogicality of a Pelopæus misled by my artifices. Is the Lamb when it
first grips the teat a free and conscious agent, capable of improvement
in its difficult art of taking nourishment? The insect is no more
capable of improvement in its art, more difficult still, of giving
nourishment.
But, with its hide-bound science ignorant of itself, pure instinct, if
it stood alone, would leave the insect unarmed in the perpetual
conflict of circumstances. No two moments in time are identical; though
the background remain the same, the details change; the unexpected
rises on every side. In this bewildering confusion, a guide is needed
to seek, accept, refuse and select; to show preference for this and
indifference to that; to turn to account, in short, anything useful
that occasion may offer. This guide the insect undoubtedly possesses,
to a very manifest degree. It is the second province of its mentality.
Here it is conscious and capable of improvement by experience. I dare
not speak of this rudimentary faculty as intelligence, which is too
exalted a title: I will call it discernment. The insect, in exercising
its highest gifts, discerns, differentiates between one thing and
another, within the sphere of its craft, of course; and that is about
all.
So long as we confound acts of pure instinct and acts of discernment
under the same head, we shall fall back into those endless discussions
which embitter controversy without bringing us one step nearer to the
solution of the problem. Is the insect conscious of what it does? Yes
and no. No, if its action falls within the domain of instinct; yes, if
the action falls within that of discernment. Are the habits of an
insect capable of modification? No, decidedly not, if the habit in
question belongs to the province of instinct; yes, if it belongs to
that of discernment. Let us state this fundamental distinction more
precisely with the aid of a few examples.
The Pelopæus builds her cells with earth already softened, with mud.
Here we have instinct, the unalterable characteristic of the worker.
She has always built in this way and always will. The passing ages will
never teach her, neither the struggle for life nor the law of selection
will ever induce her to imitate the Mason-bee and collect dry dust for
her mortar. This mud nest of hers needs a shelter against the rain. The
hiding-place under a stone suffices at first. But should she find
something better, the potter takes possession of that something better
and instals herself in the home of man. There we have discernment, the
source of some sort of capacity for improvement.
The Pelopæus supplies her larvæ with provisions in the form of Spiders.
There you have instinct. The climate, the latitude or longitude, the
changing seasons, the abundance or scarcity of game introduce no
modification into this diet, though the larva shows itself satisfied
with other fare provided by myself. Its forebears were brought up on
Spiders; their descendants consumed similar food; and their posterity
again will know no other. Not a single circumstance, however
favourable, will ever persuade the Pelopæus that young Crickets, for
instance, are as good as Spiders and that her family would accept them
gladly. Instinct binds her down to the national diet.
But, should the Epeira, the favourite prey, be lacking, must the
Pelopæus give up foraging? She will stock her warehouses all the same,
because any Spider suits her. There you have discernment, whose
elasticity makes up, in certain circumstances, for the excessive
rigidity of instinct. Amid the innumerable variety of game, the
huntress is able to discern between what is Spider and what is not; and
in this way she is always prepared to supply her family, without
quitting the domain of her instinct.
The Hairy Ammophila gives her larva a single caterpillar, a large one,
paralysed by as many pricks of her sting as it has nervous centres in
its thorax and abdomen. Her surgical skill in subduing the monster is
instinct, displayed in a form that quashes any inclination to see in it
an acquired habit. In an art that can leave no one to practise it in
the future unless that one be perfect at the outset, of what avail are
lucky chances, atavistic tendencies, or the mellowing hand of time? But
the grey caterpillar, sacrificed one day, may be succeeded on another
day by a green, yellow or striped caterpillar. There you have
discernment, which is quite capable of recognizing the regulation prey
under very diverse garbs.
The Megachiles [53] build their honey-jars with disks cut out of
leaves; certain Anthidia make felted cotton wallets; others fashion
pots out of resin. There you have instinct. Will any rash mind ever
conceive the singular idea that the Leaf-cutter might very well have
started working in cotton, that the cotton-wool-worker once thought or
will one day think of cutting disks out of the leaves of the lilac- or
the rose-tree, that the resin-kneader began with clay? Who would dare
to indulge in such theories? Each Bee has her art, her medium, to which
she strictly confines herself. The first has her leaves; the second her
wadding; the third her resin. None of these guilds has ever changed
trades with another; and none ever will. There you have instinct,
keeping the workers to their specialities. There are no innovations in
their workshops, no formulæ resulting from experiment, no ingenious
devices, no progress from the indifferent to the good, from the good to
the excellent. To-day’s method is the facsimile of yesterday’s; and
to-morrow will know no other.
But, though the manufacturing-process is invariable, the raw material
is subject to change. The plant that supplies the cotton differs in
species according to the locality; the bush out of whose leaves the
pieces will be cut is not the same in the various fields of operation;
the tree that provides the resinous putty may be a pine, a cypress, a
juniper, a cedar or a spruce, all very different in appearance. What
will guide the insect in its gleaning? Discernment.
These, I think, are sufficient details of the fundamental distinction
to be drawn in the insect’s mentality, the distinction, that is,
between pure instinct and discernment. If people confuse these two
provinces, as they nearly always do, any understanding becomes
impossible; the last glimmer of light disappears behind the clouds of
interminable discussions. From an industrial point of view, let us look
upon the insect as a worker thoroughly versed from birth in a craft
whose essential principles never vary; let us grant that unconscious
worker a gleam of intelligence which will permit it to extricate itself
from the inevitable conflict of attendant circumstances; and I think
that we shall have come as near to the truth as the state of our
knowledge will allow for the moment.
Having thus assigned a due share both to instinct and to its
aberrations when the course of its different phases is disturbed, let
us see what discernment is able to do in the selection of a site for
the nest and materials for building it; and, leaving the Pelopæus, upon
whom it is useless to dwell any longer, let us consider other examples,
picked from among those richest in variations.
The Mason-bee of the Sheds (Chalicodoma rufitarsis, Pérez) well
deserves the name which I have felt justified in giving her from her
habits: she settles in numerous colonies in our sheds, on the lower
surface of the tiles, where she builds huge nests which endanger the
solidity of the roof. Nowhere does the insect display a greater zeal
for work than in one of these colossal cities, an estate which is
constantly increasing as it passes down from one generation to another;
nowhere does it find a better workshop for the exercise of its
industry. Here it has plenty of room, a quiet resting-place, sheltered
from damp and from excess of heat or cold.
But the spacious domain under the tiles is not within the reach of all:
sheds with free access and the proper sunny aspect are pretty rare.
These sites fall only to fortune’s favourites. Where will the others
take up their quarters? More or less anywhere. Without leaving the
house in which I live, I can enumerate stone, wood, glass, metal, paint
and mortar as forming the foundation of the nests. The green-house with
its furnace heat in the summer and its bright light, equalling that
outside, is fairly well-frequented. The Mason-bee hardly ever fails to
build there each year, in squads of a few dozen, now on the glass
panes, now on the iron bars of the framework. Other little swarms
settle in the window-embrasures, under the projecting ledge of the
front-door or in the cranny between the wall and an open shutter. Yet
others, being perhaps of a morose disposition, flee society and prefer
to work in solitude, one in the inside of a lock or of a pipe intended
to carry the rain-water from the leads; another in the mouldings of the
doors and windows or in the crude ornamentation of the stonework. In
short, the house is made use of all round, provided that the shelter be
an out-of-door one; for observe that the enterprising invader, unlike
the Pelopæus, never penetrates inside our dwellings. The case of the
conservatory is an exception more apparent than real: the glass
building, standing wide open throughout the summer, is to the Mason-bee
but a shed a little lighter than another. There is nothing here to
arouse the distrust with which anything indoors or closed inspires her.
To build on the threshold of an outer door, to usurp its lock, a
hiding-place to her fancy, is all that she allows herself; to go any
farther is an adventure repugnant to her taste.
Lastly, in the case of all these dwellings, the Mason-bee is man’s free
tenant; her industry makes use of the products of our own industry. Can
she have no other establishments? She has, beyond a doubt; she
possesses some constructed on the ancient plan. On a stone the size of
a man’s fist, protected by the shelter of a hedge, sometimes even on a
pebble in the open air, I see her building now groups of cells as large
as a walnut, now domes emulating in size, shape and solidity those of
her rival, the Mason-bee of the Walls.
The stone support is the most frequent, though not the only one. I have
found nests, but sparsely inhabited it is true, on the trunks of trees,
in the seams of the rough bark of oaks. Among those whose support was a
living plant, I will mention two that stand out above all the others.
The first was built in the grooves of a Peruvian torch-thistle as thick
as my leg; the second rested on a stalk of the opuntia, the Indian fig.
Had the fierce armour of these two stout cactuses attracted the
attention of the insect, which looked upon their tufts of spikes as
furnishing a system of defence for its nest? Perhaps so. In any case,
the attempt was not imitated; I never saw another installation of the
kind. There is one definite conclusion to be drawn from my two
discoveries. Despite the oddity of their structure, which is
unparalleled in the local flora, the two American importations did not
compel the insect to go through an apprenticeship of groping and
hesitation. The one which found itself in the presence of those novel
growths and which was perhaps the first of its race to do so took
possession of their grooves and stalks just as it would have done of a
familiar site. From the start, the fleshy plants from the New World
suited it quite as well as the trunk of a native tree.
The Mason-bee of the Pebbles (Chalicodoma parietina) has none of this
elasticity in the choice of a site. In her case, the smooth stone of
the parched uplands is the almost invariable foundation of her
structures. Elsewhere, under a less clement sky, she prefers the
support of a wall, which protects the nest against the prolonged snows.
Lastly, the Mason-bee of the Shrubs (C. rufescens, Pérez) fixes her
ball of clay to a twig of any ligneous plant, from the thyme, the
rock-rose and the heath to the oak, the elm and the pine. The list of
the sites that suit her would almost form a complete catalogue of the
ligneous flora.
The variety of places where the insect installs itself, so eloquent of
the part played by discernment in their selection, becomes still more
remarkable when accompanied by a corresponding variety in the
architecture of the cells. This is more particularly the case with the
Three-horned Osmia, [54] who, as she uses clayey materials very easily
affected by the rain, requires, like the Pelopæus, a dry shelter for
her cells, a shelter which she finds ready-made and uses just as it is,
after a few touches by way of sweeping and cleansing. The homes which I
see her adopt are especially the shells of Snails that have died under
the stone-heaps and in the low, unmortared walls which support the
cultivated earth of the hills in shelves or terraces. The use of
Snail-shells is accompanied by the no less active use of the old cells
of both the Mason-bee of the Sheds and of certain Anthophoræ (A.
pilipes, A. parietina and A. personata.) [55]
We must not forget the reed, which is highly appreciated when—a rare
find—it appears under the desired conditions. In its natural state, the
plant with the mighty hollow cylinders is of no possible use to the
Osmia, who knows nothing of the art of perforating a woody wall. The
gallery of an internode has to be wide open before the Bee can take
possession of it. Also, the clean-cut stump must be horizontal,
otherwise the rain would soften the fragile edifice of clay and soon
lay it low; also, the stump must not be lying on the ground and must be
kept at some distance from the dampness of the soil. We see therefore
that, without the intervention of man, involuntary in the vast majority
of cases and deliberate only on the experimenter’s part, the Osmia
would hardly ever find a reed-stump suited to the installation of her
family. It is to her a casual acquisition, a home unknown to her race
before men took it into their heads to cut reeds and make them into
hurdles for drying figs in the sun.
How did the work of man’s pruning-knife bring about the abandonment of
the natural lodging? How was the spiral staircase of the Snail-shell
replaced by the cylindrical gallery of the reed? Was the change from
one kind of house to another effected by gradual transitions, by
attempts made, abandoned, resumed, becoming more and more definite in
their results as generation succeeded generation? Or did the Osmia,
finding the cut reed that answered her requirements, install herself
there straightway, scorning her ancient dwelling, the Snail-shell?
These questions called for a reply; and they have received one. Let us
describe how things happened.
Near Sérignan are some great quarries of coarse limestone,
characteristic of the miocene formation of the Rhone valley. These have
been worked for many generations. The ancient public buildings of
Orange, notably the colossal frontage of the theatre whither all the
intellectual world once flocked to hear Sophocles’ Œdipus Tyrannus,
derive most of their material from these quarries. Other evidence
confirms what the similarity of the hewn stone tells us. Among the
rubbish that fills up the spaces between the tiers of seats, they
occasionally discover the Marseilles obol, a bit of silver stamped with
the four-spoked wheel, or a few bronze coins bearing the effigy of
Augustus or Tiberius. Scattered also here and there among the monuments
of antiquity are heaps of refuse, accumulations of broken stones in
which various Bees and Wasps, including the Three-horned Osmia in
particular, take possession of the dead Snail-shell.
The quarries form part of an extensive plateau which is so arid as to
be nearly deserted. In these conditions, the Osmia, at all times
faithful to her birth-place, has little or no need to emigrate from her
heap of stones and leave the shell for another dwelling which she would
be obliged to seek at a distance. Since there are heaps of stone there,
she probably has no other dwelling than the Snail-shell. Nothing tells
us that the present-day generations are not descended in the direct
line from the generations contemporary with the quarry-man who lost his
as or his obol at this spot. All the circumstances seem to point to it:
the Osmia of the quarries is an inveterate user of Snail-shells; so far
as heredity is concerned, she knows nothing whatever of reeds. Well, we
must place her in the presence of these new lodgings.
I collect during the winter about two dozen well-stocked Snail-shells
and install them in a quiet corner of my study, as I did at the time of
my enquiries into the distribution of the sexes. [56] The little hive
with its front pierced with forty holes has bits of reed fitted to it.
At the foot of the five rows of cylinders I place the inhabited shells
and with these I mix a few small stones, the better to imitate the
natural conditions. I add an assortment of empty Snail-shells, after
carefully cleaning the interior so as to make the Osmia’s stay more
pleasant. When the time comes for nest-building, the stay-at-home
insect will have, close beside the house of its birth, a choice of two
habitations: the cylinder, a novelty unknown to its race; and the
spiral staircase, the ancient ancestral home.
The nests were finished at the end of May and the Osmiæ began to answer
my interrogatory. Some of them, the great majority, settled exclusively
in the reeds; the others remained faithful to the Snail-shell, or else
entrusted their eggs partly to the spirals and partly to the cylinders.
With the first, who were the pioneers of cylindrical architecture,
there was no hesitation that I could perceive: after exploring the
stump of reed for a time and recognizing it as serviceable, the insect
installs itself there and, an expert from the first touch, without
apprenticeship, without groping, without any tendencies bequeathed by
the long practice of its predecessors, builds its straight row of cells
on a very different plan from that demanded by the spiral cavity of the
shell, which increases in size as it goes on.
The slow school of the ages, the gradual acquisitions of the past, the
legacies of heredity count for nothing, therefore, in the Osmia’s
education. Without any noviciate on its own part or that of its
forebears, the insect is versed straight away in the calling which it
has to pursue; it possesses, inseparable from its nature, the qualities
demanded by its craft: some which are invariable and belong to the
province of instinct; others which are flexible and belong to the
province of discernment. To divide a free lodging into chambers by
means of mud partitions; to fill these chambers with a heap of
pollen-flour, with a few sups of honey in the central part where the
egg is to lie; in short, to prepare board and lodging for the unknown,
for a family which the mothers have never seen in the past and will
never see in the future: this, in its essential features, is the
function of the Osmia’s instinct. Here, everything is harmoniously,
inflexibly, permanently preordained; the insect has but to follow its
blind impulse to attain the goal. But the free lodging offered by
chance varies exceedingly in hygienic conditions, in shape and in
capacity. Instinct, which does not choose, which does not contrive,
would, if it were alone, leave the insect’s existence in peril. To help
her out of her predicament, in these complex circumstances, the Osmia
possesses her little stock of discernment, which distinguishes between
the dry and the wet, the solid and the fragile, the sheltered and the
exposed; which recognizes the worth or worthlessness of a site and
knows how to sprinkle it with cells according to the size and shape of
the space at its disposal. Here, slight industrial variations are
necessary and inevitable; and the insect excels in them without any
apprenticeship, as the experiment with the Osmia born in the quarries
has proved.
Animal resources have a certain elasticity within narrow limits. What
we learn from the animals’ industry at a given moment is not always the
full measure of their skill. They possess latent powers held in reserve
for certain emergencies. Long generations can succeed one another
without employing them; but, should some circumstance require it,
suddenly those powers burst forth, free of any previous attempts, even
as the spark potentially contained in the flint flashes forth
independently of all preceding gleams. Could one who knew nothing of
the Sparrow except the nest under the eaves suspect the ball-shaped
nest at the top of a tree? Would one who knew nothing of the Osmia save
her home in the Snail-shell expect to see her accept as her dwelling a
stump of reed, a paper funnel, a glass tube? My neighbour the Sparrow,
impulsively taking it into his head to leave the roof for the
plane-tree, the Osmia of the quarries, rejecting her natal cabin, the
Snail-shell, for my cylinders, alike show us how sudden and spontaneous
are animals’ industrial variations.