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INSTINCT AND DISCERNMENT




The Pelopaeus (A Mason-wasp forming the subject of essays which have
not yet been published in English.--Translator's Note.) gives us a
very poor idea of her intellect when she plasters up 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 forceps
has left empty, extracting alike germ and provisions. The Mason-bees
(Cf. "The Mason-bees": chapter 7.--Translator's Note.), the
caterpillar of the Great Peacock Moth (Cf. "Social Life in the Insect
World" by J.H. Fabre, translated by Bernard Miall: chapter 14.--
Translator's Note.) 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 them all useless. Just like millstones unable to
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. 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 clock-work 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 which is able to explain the monstrous
illogicality of a Pelopaeus when 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 insect, 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 business, of course; and that is about all.

As 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 is in the province of
instinct; yes, if the action is in 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 by the aid of a few examples.

The Pelopaeus 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 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. (The
Pelopaeus builds in the fire-places of houses.--Translator's Note.)
There we have discernment, the source of some sort of capacity for
improvement.

The Pelopaeus supplies her larvae with provisions in the form of
Spiders. There you have instinct. The climate, the longitude or
latitude, 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 Pelopaeus
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 Weaving or Garden Spider. Cf. "The Life
of the Spider" by J. Henri Fabre translated by Alexander Teixeira de
Mattos; chapters 9 to 14 and appendix.--Translator's Note.), the
favourite prey, be lacking, must the Pelopaeus therefore 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 too-great 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 which makes short work of 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 happy chances, atavistic tendencies, 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 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- and
the rose-tree, that the resin-kneader began with clay? Who would dare
to indulge in any 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 recipes resulting from experiment,
no ingenious devices, no progress from indifferent to good, from good
to 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 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 the aberrations
of instinct 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 Pelopaeus,
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, PEREZ) 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 the favoured of fortune. Where will
the others take up their quarters? More or less everywhere. 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 apiece, 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. Others again, 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 stone-work. 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 Pelopaeus,
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 the others. There is nothing here to arouse the
distrust with which anything indoors or shut up inspires her. To
build on the threshold of an outer door, or 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 lobe of a 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 among 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 lobes and stalks
just as it would have done of a familiar site. From the start, the
fleshy plants from the New World suited it 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 (Chalicodoma rufescens,
PEREZ) 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 wherein the insect instals itself, so eloquent
of the part played by discernment in their selection, becomes still
more remarkable when it is accompanied by a corresponding variety in
the architecture of the cells. This is more particularly the case
with the Three-horned Osmia, who, as she uses clayey materials very
easily affected by the rain, requires, like the Pelopaeus, 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 Anthophorae (A. pilipes, A. parietina and A. personata).

We must not forget the reed, which is highly appreciated when--a rare
find--it appears under the requisite 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
insect 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, instal 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 Serignan 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' "Oedipus
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 Hymenoptera,
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 have to go and 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
quarryman 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 instal them in a quiet corner of my study, as I did at the time
of my enquiries into the distribution of the sexes. 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 Osmiae began to
answer my list of questions. Some, 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 instals 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 novitiate 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 domain of instinct; others, flexible, belonging to the
province of discernment. To divide a free lodging into chambers by
means of mud partitions; to fill those 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
the worthlessness of a site and knows how to sprinkle it with cells
according to the size and shape of the space at disposal. Here,
slight industrial variations are necessary and inevitable; and the
insect excels in them without any apprenticeship, as the experiment
with the native Osmia of the quarries has just 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 but her 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 her head to leave
the roof for the plane-tree, the Osmia of the quarries, rejecting her
natal cabin, the spiral of the shell, for my cylinder, alike show us
how sudden and spontaneous are the industrial variations of animals.





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