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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 empt
, 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


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


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.