The Mason-bees
by
J. Henri Fabre
Part 2 out of 4
At five o'clock, the arrivals number seven of the pink Mason-bees,
whom I thought that I had bewildered by a long and circuitous drive,
and six of the blue Mason-bees, who came to Font-Claire by the direct
route. The two proportions, forty-six and forty per cent., are almost
equal; and the slight excess in favour of the insects that went the
roundabout way is evidently an accidental result which we need not
take into consideration. The bend described cannot have helped them to
find their way home; but it has also certainly not hampered them.
There is no need of further proof. The intricate movements of a
rotation such as I have described; the obstacle of hills and woods;
the pitfalls of a road which moves on, moves back and returns after
making a wide circuit: none of these is able to disconcert the
Chalicodomae or prevent them from going back to the nest.
I had written to Charles Darwin telling him of my first, negative
results, those obtained by swinging the Bees in a box. He expected a
success and was much surprised at the failure. Had he had time to
experiment with his Pigeons, they would have behaved just like my
Bees; the preliminary twirling would not have affected them. The
problem called for another method; and what he proposed was this:
'To place the insect within an induction coil, so as to disturb any
magnetic or diamagnetic sensibility which it seems just possible that
they may possess.'
To treat an insect as you would a magnetic needle and to subject it to
the current from an induction coil in order to disturb its magnetism
or diamagnetism appeared to me, I must confess, a curious notion,
worthy of an imagination in the last ditch. I have but little
confidence in our physics, when they pretend to explain life;
nevertheless, my respect for the great man would have made me resort
to the induction-coils, if I had possessed the necessary apparatus.
But my village boasts no scientific resources: if I want an electric
spark, I am reduced to rubbing a sheet of paper on my knees. My
physics cupboard contains a magnet; and that is about all. When this
penury was realised, another method was suggested, simpler than the
first and more certain in its results, as Darwin himself considered:
'To make a very thin needle into a magnet; then breaking it into very
short pieces, which would still be magnetic, and fastening one of
these pieces with some cement on the thorax of the insects to be
experimented on. I believe that such a little magnet, from its close
proximity to the nervous system of the insect, would affect it more
than would the terrestrial currents.'
There is still the same idea of turning the insect into a sort of bar
magnet. The terrestrial currents guide it when returning to the nest.
It becomes a living compass which, withdrawn from the action of the
earth by the proximity of a loadstone, loses its sense of direction.
With a tiny magnet fastened on its thorax, parallel with the nervous
system and more powerful than the terrestrial magnetism by reason of
its comparative nearness, the insect will lose its bearings.
Naturally, in setting down these lines, I take shelter behind the
mighty reputation of the learned begetter of the idea. It would not be
accepted as serious coming from a humble person like myself. Obscurity
cannot afford these audacious theories.
The experiment seems easy; it is not beyond the means at my disposal.
Let us attempt it. I magnetise a very fine needle by rubbing it with
my bar magnet; I retain only the slenderest part, the point, some five
or six millimetres long. (.2 to .23 inch.--Translator's Note.) This
broken piece is a perfect magnet: it attracts and repels another
magnetised needle hanging from a thread. I am a little puzzled as to
the best way to fasten it on the insect's thorax. My assistant of the
moment, the pharmaceutical student, requisitions all the adhesives in
his laboratory. The best is a sort of cerecloth which he prepares
specially with a very fine material. It possesses the advantage that
it can be softened at the bowl of one's pipe when the time comes to
operate out of doors.
I cut out of this cerecloth a small square the size of the Bee's
thorax; and I insert the magnetised point through a few threads of the
material. All that we now have to do is to soften the gum a little and
then dab the thing at once on the Mason-bee's back, so that the broken
needle runs parallel with the spine. Other engines of the same kind
are prepared and due note taken of their poles, so as to enable me to
point the south pole at the insect's head in some cases and at the
opposite end in others.
My assistant and I begin by rehearsing the performance; we must have a
little practice before trying the experiment away from home. Besides,
I want to see how the insect will behave in its magnetic harness. I
take a Mason-bee at work in her cell, which I mark. I carry her to my
study, at the other end of the house. The magnetised outfit is
fastened on the thorax; and the insect is let go. The moment she is
free, the Bee drops to the ground and rolls about, like a mad thing,
on the floor of the room. She resumes her flight, flops down again,
turns over on her side, on her back, knocks against the things in her
way, buzzes noisily, flings herself about desperately and ends by
darting through the open window in headlong flight.
What does it all mean? The magnet appears to have a curious effect on
my patient's system! What a fuss she makes! How terrified she is! The
Bee seemed utterly distraught at losing her bearings under the
influence of my knavish tricks. Let us go to the nests and see what
happens. We have not long to wait: my insect returns, but rid of its
magnetic tackle. I recognize it by the traces of gum that still cling
to the hair of the thorax. It goes back to its cell and resumes its
labours.
Always on my guard when searching the unknown, unwilling to draw
conclusions before weighing the arguments for and against, I feel
doubt creeping in upon me with regard to what I have seen. Was it
really the magnetic influence that disturbed my Bee so strangely? When
she struggled and kicked on the floor, fighting wildly with both legs
and wings, when she fled in terror, was she under the sway of the
magnet fastened on her back? Can my appliance have thwarted the
guiding influence of the terrestrial currents on her nervous system?
Or was her distress merely the result of an unwonted harness? This is
what remains to be seen and that without delay.
I construct a new apparatus, but provide it with a short straw in
place of the magnet. The insect carrying it on its back rolls on the
ground, kicks and flings herself about like the first, until the
irksome contrivance is removed, taking with it a part of the fur on
the thorax. The straw produces the same effects as the magnet, in
other words, magnetism had nothing to do with what happened. My
invention, in both cases alike, is a cumbrous tackle of which the Bee
tries to rid herself at once by every possible means. To look to her
for normal actions so long as she carries an apparatus, magnetized or
not, upon her back is the same as expecting to study the natural
habits of a Dog after tying a kettle to his tail.
The experiment with the magnet is impracticable. What would it tell us
if the insect consented to it? In my opinion, it would tell us
nothing. In the matter of the homing instinct, a magnet would have no
more influence than a bit of straw.
CHAPTER 5. THE STORY OF MY CATS.
If this swinging-process fails entirely when its object is to make the
insect lose its bearings, what influence can it have upon the Cat? Is
the method of whirling the animal round in a bag, to prevent its
return, worthy of confidence? I believed in it at first, so close-
allied was it to the hopeful idea suggested by the great Darwin. But
my faith is now shaken: my experience with the insect makes me
doubtful of the Cat. If the former returns after being whirled, why
should not the latter? I therefore embark upon fresh experiments.
And, first of all, to what extent does the Cat deserve his reputation
of being able to return to the beloved home, to the scenes of his
amorous exploits on the tiles and in the hay-lofts? The most curious
facts are told of his instinct; children's books on natural history
abound with feats that do the greatest credit to his prowess as a
pilgrim. I do not attach much importance to these stories: they come
from casual observers, uncritical folk given to exaggeration. It is
not everybody who can talk about animals correctly. When some one not
of the craft gets on the subject and says to me, 'Such or such an
animal is black,' I begin by finding out if it does not happen to be
white; and many a time the truth is discovered in the converse
proposition. Men come to me and sing the praises of the Cat as a
travelling-expert. Well and good: we will now look upon the Cat as a
poor traveller. And that would be the extent of my knowledge if I had
only the evidence of books and of people unaccustomed to the scruples
of scientific examination. Fortunately, I am acquainted with a few
incidents that will stand the test of my incredulity. The Cat really
deserves his reputation as a discerning pilgrim. Let us relate these
incidents.
One day--it was at Avignon--there appeared upon the garden-wall a
wretched-looking Cat, with matted coat and protruding ribs, so thin
that his back was a mere jagged ridge. He was mewing with hunger. My
children, at that time very young, took pity on his misery. Bread
soaked in milk was offered him at the end of a reed. He took it. And
the mouthfuls succeeded one another to such good purpose that he was
sated and went off, heedless of the 'Puss! Puss!' of his compassionate
friends. Hunger returned; and the starveling reappeared in his wall-
top refectory. He received the same fare of bread soaked in milk, the
same soft words. He allowed himself to be tempted. He came down from
the wall. The children were able to stroke his back. Goodness, how
thin he was!
It was the great topic of conversation. We discussed it at table: we
would tame the vagabond, we would keep him, we would make him a bed of
hay. It was a most important matter: I can see to this day, I shall
always see the council of rattleheads deliberating on the Cat's fate.
They were not satisfied until the savage animal remained. Soon he grew
into a magnificent Tom. His large round head, his muscular legs, his
reddish fur, flecked with darker patches, reminded one of a little
jaguar. He was christened Ginger because of his tawny hue. A mate
joined him later, picked up in almost similar circumstances. Such was
the origin of my series of Gingers, which I have retained for little
short of twenty years through the vicissitudes of my various removals.
The first of these removals took place in 1870. A little earlier, a
minister who has left a lasting memory in the University, that fine
man, Victor Duruy (Jean Victor Duruy (1811-1894), author of a number
of historical works, including a well-known "Histoire des Romains",
and minister of public instruction under Napoleon III. from 1863 to
1869. Cf. "The Life of the Fly": chapter 20.--Translator's Note.), had
instituted classes for the secondary education of girls. This was the
beginning, as far as was then possible, of the burning question of
to-day. I very gladly lent my humble aid to this labour of light. I
was put to teach physical and natural science. I had faith and was not
sparing of work, with the result that I rarely faced a more attentive
or interested audience. The days on which the lessons fell were red-
letter days, especially when the lesson was botany and the table
disappeared from view under the treasures of the neighbouring
conservatories.
That was going too far. In fact, you can see how heinous my crime was:
I taught those young persons what air and water are; whence the
lightning comes and the thunder; by what device our thoughts are
transmitted across the seas and continents by means of a metal wire;
why fire burns and why we breathe; how a seed puts forth shoots and
how a flower blossoms: all eminently hateful things in the eyes of
some people, whose feeble eyes are dazzled by the light of day.
The little lamp must be put out as quickly as possible and measures
taken to get rid of the officious person who strove to keep it alight.
The scheme was darkly plotted with the old maids who owned my house
and who saw the abomination of desolation in these new educational
methods. I had no written agreement to protect me. The bailiff
appeared with a notice on stamped paper. It baldly informed that I
must move out within four weeks from date, failing which the law would
turn my goods and chattels into the street. I had hurriedly to provide
myself with a dwelling. The first house which we found happened to be
at Orange. Thus was my exodus from Avignon effected.
We were somewhat anxious about the moving of the Cats. We were all of
us attached to them and should have thought it nothing short of
criminal to abandon the poor creatures, whom we had so often petted,
to distress and probably to thoughtless persecution. The shes and the
kittens would travel without any trouble: all you have to do is to put
them in a basket; they will keep quiet on the journey. But the old
Tom-cats were a serious problem. I had two: the head of the family,
the patriarch; and one of his descendants, quite as strong as himself.
We decided to take the grandsire, if he consented to come, and to
leave the grandson behind, after finding him a home.
My friend Dr. Loriol offered to take charge of the forsaken one. The
animal was carried to him at nightfall in a closed hamper. Hardly were
we seated at the evening-meal, talking of the good fortune of our Tom-
cat, when we saw a dripping mass jump through the window. The
shapeless bundle came and rubbed itself against our legs, purring with
happiness. It was the Cat.
I learnt his story next day. On arriving at Dr. Loriol's, he was
locked up in a bedroom. The moment he saw himself a prisoner in the
unfamiliar room, he began to jump about wildly on the furniture,
against the window-panes, among the ornaments on the mantelpiece,
threatening to make short work of everything. Mme. Loriol was
frightened by the little lunatic; she hastened to open the window; and
the Cat leapt out among the passers-by. A few minutes later, he was
back at home. And it was no easy matter: he had to cross the town
almost from end to end; he had to make his way through a long
labyrinth of crowded streets, amid a thousand dangers, including first
boys and next dogs; lastly--and this perhaps was an even more serious
obstacle--he had to pass over the Sorgue, a river running through
Avignon. There were bridges at hand, many, in fact; but the animal,
taking the shortest cut, had used none of them, bravely jumping into
the water, as its streaming fur showed. I had pity on the poor Cat, so
faithful to his home. We agreed to do our utmost to take him with us.
We were spared the worry: a few days later, he was found lying stiff
and stark under a shrub in the garden. The plucky animal had fallen a
victim to some stupid act of spite. Some one had poisoned him for me.
Who? It is not likely that it was a friend!
There remained the old Cat. He was not indoors when we started; he was
prowling round the hay-lofts of the neighbourhood. The carrier was
promised an extra ten francs if he brought the Cat to Orange with one
of the loads which he had still to convey. On his last journey he
brought him stowed away under the driver's seat. I scarcely knew my
old Tom when we opened the moving prison in which he had been confined
since the day before. He came out looking a most alarming beast,
scratching and spitting, with bristling hair, bloodshot eyes, lips
white with foam. I thought him mad and watched him closely for a time.
I was wrong: it was merely the fright of a bewildered animal. Had
there been trouble with the carrier when he was caught? Did he have a
bad time on the journey? History is silent on both points. What I do
know is that the very nature of the Cat seemed changed: there was no
more friendly purring, no more rubbing against our legs; nothing but a
wild expression and the deepest gloom. Kind treatment could not soothe
him. For a few weeks longer, he dragged his wretched existence from
corner to corner; then, one day, I found him lying dead in the ashes
on the hearth. Grief, with the help of old age, had killed him. Would
he have gone back to Avignon, had he had the strength? I would not
venture to affirm it. But, at least, I think it very remarkable that
an animal should let itself die of home-sickness because the
infirmities of age prevent it from returning to its old haunts.
What the patriarch could not attempt, we shall see another do, over a
much shorter distance, I admit. A fresh move is resolved upon, that I
may have, at length, the peace and quiet essential to my work. This
time, I hope that it will be the last. I leave Orange for Serignan.
The family of Gingers has been renewed: the old ones have passed away,
new ones have come, including a full-grown Tom, worthy in all respects
of his ancestors. He alone will give us some difficulty; the others,
the babies and the mothers, can be removed without trouble. We put
them into baskets. The Tom has one to himself, so that the peace may
be kept. The journey is made by carriage, in company with my family.
Nothing striking happens before our arrival. Released from their
hampers, the females inspect the new home, explore the rooms one by
one; with their pink noses they recognize the furniture: they find
their own seats, their own tables, their own arm-chairs; but the
surroundings are different. They give little surprised miaows and
questioning glances. A few caresses and a saucer of milk allay all
their apprehensions; and, by the next day, the mother Cats are
acclimatised.
It is a different matter with the Tom. We house him in the attics,
where he will find ample room for his capers; we keep him company, to
relieve the weariness of captivity; we take him a double portion of
plates to lick; from time to time, we place him in touch with some of
his family, to show him that he is not alone in the house; we pay him
a host of attentions, in the hope of making him forget Orange. He
appears, in fact, to forget it: he is gentle under the hand that pets
him, he comes when called, purrs, arches his back. It is well: a week
of seclusion and kindly treatment have banished all notions of
returning. Let us give him his liberty. He goes down to the kitchen,
stands by the table like the others, goes out into the garden, under
the watchful eye of Aglae, who does not lose sight of him; he prowls
all around with the most innocent air. He comes back. Victory! The
Tom-cat will not run away.
Next morning:
'Puss! Puss!'
Not a sign of him! We hunt, we call. Nothing. Oh, the hypocrite, the
hypocrite! How he has tricked us! He has gone, he is at Orange. None
of those about me can believe in this venturesome pilgrimage. I
declare that the deserter is at this moment at Orange mewing outside
the empty house.
Aglae and Claire went to Orange. They found the Cat, as I said they
would, and brought him back in a hamper. His paws and belly were
covered with red clay; and yet the weather was dry, there was no mud.
The Cat, therefore, must have got wet crossing the Aygues torrent; and
the moist fur had kept the red earth of the fields through which he
passed. The distance from Serignan to Orange, in a straight line, is
four and a half miles. There are two bridges over the Aygues, one
above and one below that line, some distance away. The Cat took
neither the one nor the other: his instinct told him the shortest road
and he followed that road, as his belly, covered with red mud, proved.
He crossed the torrent in May, at a time when the rivers run high; he
overcame his repugnance to water in order to return to his beloved
home. The Avignon Tom did the same when crossing the Sorgue.
The deserter was reinstated in his attic at Serignan. He stayed there
for a fortnight; and at last we let him out. Twenty-four hours had not
elapsed before he was back at Orange. We had to abandon him to his
unhappy fate. A neighbour living out in the country, near my former
house, told me that he saw him one day hiding behind a hedge with a
rabbit in his mouth. Once no longer provided with food, he, accustomed
to all the sweets of a Cat's existence, turned poacher, taking toll of
the farm-yards round about my old home. I heard no more of him. He
came to a bad end, no doubt: he had become a robber and must have met
with a robber's fate.
The experiment has been made and here is the conclusion, twice proved.
Full-grown Cats can find their way home, in spite of the distance and
their complete ignorance of the intervening ground. They have, in
their own fashion, the instinct of my Mason-bees. A second point
remains to be cleared up, that of the swinging motion in the bag. Are
they thrown out of their latitude by this stratagem, are or they not?
I was thinking of making some experiments, when more precise
information arrived and taught me that it was not necessary. The first
who acquainted me with the method of the revolving bag was telling the
story told him by a second person, who repeated the story of a third,
a story related on the authority of a fourth; and so on. None had
tried it, none had seen it for himself. It is a tradition of the
country-side. One and all extol it as an infallible method, without,
for the most part, having attempted it. And the reason which they give
for its success is, in their eyes, conclusive. If, say they, we
ourselves are blind-folded and then spin round for a few seconds, we
no longer know where we are. Even so with the Cat carried off in the
darkness of the swinging bag. They argue from man to the animal, just
as others argue from the animal to man: a faulty method in either
case, if there really be two distinct psychic worlds.
The belief would not be so deep-rooted in the peasant's mind, if facts
had not from time to time confirmed it. But we may assume that, in
successful cases, the Cats made to lose their bearings were young and
unemancipated animals. With those neophytes, a drop of milk is enough
to dispel the grief of exile. They do not return home, whether they
have been whirled in a bag or not. People have thought it as well to
subject them to the whirling operation by way of an additional
precaution; and the method has received the credit of a success that
has nothing to do with it. In order to test the method properly, it
should have been tried on a full-grown Cat, a genuine Tom.
I did in the end get the evidence which I wanted on this point.
Intelligent and trustworthy people, not given to jumping to
conclusions, have told me that they have tried the trick of the
swinging bag to keep Cats from returning to their homes. None of them
succeeded when the animal was full-grown. Though carried to a great
distance, into another house, and subjected to a conscientious series
of revolutions, the Cat always came back. I have in mind more
particularly a destroyer of the Goldfish in a fountain, who, when
transported from Serignan to Piolenc, according to the time-honoured
method, returned to his fish; who, when carried into the mountain and
left in the woods, returned once more. The bag and the swinging round
proved of no avail; and the miscreant had to be put to death. I have
verified a fair number of similar instances, all under most favourable
conditions. The evidence is unanimous: the revolving motion never
keeps the adult Cat from returning home. The popular belief, which I
found so seductive at first, is a country prejudice, based upon
imperfect observation. We must, therefore, abandon Darwin's idea when
trying to explain the homing of the Cat as well as of the Mason-bee.
CHAPTER 6. THE RED ANTS.
The Pigeon transported for hundreds of miles is able to find his way
back to his Dove-cot; the Swallow, returning from his winter quarters
in Africa, crosses the sea and once more takes possession of the old
nest. What guides them on these long journeys? Is it sight? An
observer of supreme intelligence, one who, though surpassed by others
in the knowledge of the stuffed animal under a glass case, is almost
unrivalled in his knowledge of the live animal in its wild state,
Toussenel (Alphonse Toussenel (1803-1885), the author of a number of
interesting and valuable works on ornithology.--Translator's Note.),
the admirable writer of "L'Esprit des betes", speaks of sight and
meteorology as the Carrier-pigeon's guides:
'The French bird,' he says, 'knows by experience that the cold weather
comes from the north, the hot from the south, the dry from the east
and the wet from the west. That is enough meteorological knowledge to
tell him the cardinal points and to direct his flight. The Pigeon
taken in a closed basket from Brussels to Toulouse has certainly no
means of reading the map of the route with his eyes; but no one can
prevent him from feeling, by the warmth of the atmosphere, that he is
pursuing the road to the south. When restored to liberty at Toulouse,
he already knows that the direction which he must follow to regain his
Dove-cot is the direction of the north. Therefore he wings straight in
that direction and does not stop until he nears those latitudes where
the mean temperature is that of the zone which he inhabits. If he does
not find his home at the first onset, it is because he has borne a
little too much to the right or to the left. In any case, it takes him
but a few hours' search in an easterly or westerly direction to
correct his mistake.'
The explanation is a tempting one when the journey is taken north and
south; but it does not apply to a journey east and west, on the same
isothermal line. Besides, it has this defect, that it does not admit
of generalization. One cannot talk of sight and still less of the
influence of a change of climate when a Cat returns home, from one end
of a town to the other, threading his way through a labyrinth of
streets and alleys which he sees for the first time. Nor is it sight
that guides my Mason-bees, especially when they are let loose in the
thick of a wood. Their low flight, eight or nine feet above the
ground, does not allow them to take a panoramic view nor to gather the
lie of the land. What need have they of topography? Their hesitation
is short-lived: after describing a few narrow circles around the
experimenter, they start in the direction of the nest, despite the
cover of the forest, despite the screen of a tall chain of hills which
they cross by mounting the slope at no great height from the ground.
Sight enables them to avoid obstacles, without giving them a general
idea of their road. Nor has meteorology aught to do with the case: the
climate has not varied in those few miles of transit. My Mason-bees
have not learnt from any experience of heat, cold, dryness and damp:
an existence of a few weeks' duration does not allow of this. And,
even if they knew all about the four cardinal points, there is no
difference in climate between the spot where their nest lies and the
spot at which they are released; so that does not help them to settle
the direction in which they are to travel.
To explain these many mysteries, we are driven therefore to appeal to
yet another mystery, that is to say, a special sense denied to
mankind. Charles Darwin, whose weighty authority no one will gainsay,
arrives at the same conclusion. To ask if the animal be not impressed
by the terrestrial currents, to enquire if it be not influenced by the
close proximity of a magnetic needle: what is this but the recognition
of a magnetic sense? Do we possess a similar faculty? I am speaking,
of course, of the magnetism of the physicists and not of the magnetism
of the Mesmers and Cagliostros. Assuredly we possess nothing remotely
like it. What need would the mariner have of a compass, were he
himself a compass?
And this is what the great scientist acknowledges: a special sense, so
foreign to our organism that we are not able to form a conception of
it, guides the Pigeon, the Swallow, the Cat, the Mason-bee and a host
of others when away from home. Whether this sense be magnetic or no I
will not take upon myself to decide; I am content to have helped, in
no small degree, to establish its existence. A new sense added to our
number: what an acquisition, what a source of progress! Why are we
deprived of it? It would have been a fine weapon and of great service
in the struggle for life. If, as is contended, the whole of the animal
kingdom, including man, is derived from a single mould, the original
cell, and becomes self-evolved in the course of time, favouring the
best-endowed and leaving the less well-endowed to perish, how comes it
that this wonderful sense is the portion of a humble few and that it
has left no trace in man, the culminating achievement of the
zoological progression? Our precursors were very ill-advised to let so
magnificent an inheritance go: it was better worth keeping than a
vertebra of the coccyx or a hair of the moustache.
Does not the fact that this sense has not been handed down to us point
to a flaw in the pedigree? I submit the little problem to the
evolutionists; and I should much like to know what their protoplasm
and their nucleus have to say to it.
Is this unknown sense localized in a particular part of the Wasp and
the Bee? Is it exercised by means of a special organ? We immediately
think of the antennae. The antennae are what we always fall back upon
when the insect's actions are not quite clear to us; we gladly put
down to them whatever is most necessary to our arguments. For that
matter, I had plenty of fairly good reasons for suspecting them of
containing the sense of direction. When the Hairy Ammophila (A Sand-
wasp who hunts the Grey Worm, or Caterpillar of the Turnip-moth, to
serve as food for her grubs. For other varieties of the Ammophila, cf.
"Insect Life": chapter 15.--Translator's Note.) is searching for the
Grey Worm, it is with her antennae, those tiny fingers continually
fumbling at the soil, that she seems to recognize the presence of the
underground prey. Could not those inquisitive filaments, which seem to
guide the insect when hunting, also guide it when travelling? This
remained to be seen; and I did see.
I took some Mason-bees and amputated their antennae with the scissors,
as closely as I could. These maimed ones were then carried to a
distance and released. They returned to the nest with as little
difficulty as the others. I once experimented in the same way with the
largest of our Cerceres (Cerceris tuberculata) (Another Hunting Wasp,
who feeds her young on Weevils. Cf. "Insect Life": chapters 4 and 5.--
Translator's Note.); and the Weevil-huntress returned to her
galleries. This rids us of one hypothesis: the sense of direction is
not exercised by the antennae. Then where is its seat? I do not know.
What I do know is that the Mason-bees without antennae, though they go
back to the cells, do not resume work. They persist in flying in front
of their masonry, they alight on the clay cup, they perch on the rim
of the cell and there, seemingly pensive and forlorn, stand for a long
time contemplating the work which will never be finished; they go off,
they come back, they drive away any importunate neighbour, but they
fetch and carry no more honey or mortar. The next day, they do not
appear. Deprived of her tools, the worker loses all heart in her task.
When the Mason-bee is building, the antennae are constantly feeling,
fumbling and exploring, superintending, as it were, the finishing
touches given to the work. They are her instruments of precision; they
represent the builder's compasses, square, level and plumb-line.
Hitherto my experiments have been confined to the females, who are
much more faithful to the nest by virtue of their maternal
responsibilities. What would the males do if they were taken from
home? I have no great confidence in these swains who, for a few days,
form a tumultuous throng outside the nests, wait for the females to
emerge, quarrel for their possession, amid endless brawls, and then
disappear when the works are in full swing. What care they, I ask
myself, about returning to the natal nest rather than settling
elsewhere, provided that they find some recipient for their amatory
declarations? I was mistaken: the males do return to the nest. It is
true that, in view of their lack of strength, I did not subject them
to a long journey: about half a mile or so. Nevertheless, this
represented to them a distant expedition, an unknown country; for I do
not see them go on long excursions. By day, they visit the nests or
the flowers in the garden; at night, they take refuge in the old
galleries or in the interstices of the stone-heaps in the harmas.
The same nests are frequented by two Osmia-bees (Osmia tricornis and
Osmia Latreillii), who build their cells in the galleries left at
their disposal by the Chalicodomae. The most numerous is the first,
the Three-horned Osmia. It was a splendid opportunity to try and
discover to what extent the sense of direction may be regarded as
general in the Bees and Wasps; and I took advantage of it. Well, the
Osmiae (Osmia tricornis), both male and female, can find their way
back to the nest. My experiments were made very quickly, with small
numbers and over short distances; but the results agreed so closely
with the others that I was convinced. All told, the return to the
nest, including my earlier attempts, was verified in the case of four
species: the Chalicodoma of the Sheds, the Chalicodoma of the Walls,
the Three-horned Osmia and the Great or Warted Cerceris (Cerceris
tuberculata). ("Insect Life": chapter 19.--Translator's Note.) Shall I
generalize without reserve and allow all the Hymenoptera (The
Hymenoptera are an order of insects having four membranous wings and
include the Bees, Wasps, Ants, Saw-flies and Ichneumon-flies.--
Translator's Note.) this faculty of finding their way in unknown
country? I shall do nothing of the kind; for here, to my knowledge, is
a contradictory and very significant result.
Among the treasures of my harmas-laboratory, I place in the first rank
an Ant-hill of Polyergus rufescens, the celebrated Red Ant, the slave-
hunting Amazon. Unable to rear her family, incapable of seeking her
food, of taking it even when it is within her reach, she needs
servants who feed her and undertake the duties of housekeeping. The
Red Ants make a practice of stealing children to wait on the
community. They ransack the neighbouring Ant-hills, the home of a
different species; they carry away nymphs, which soon attain maturity
in the strange house and become willing and industrious servants.
When the hot weather of June and July sets in, I often see the Amazons
leave their barracks of an afternoon and start on an expedition. The
column measures five or six yards in length. If nothing worthy of
attention be met upon the road, the ranks are fairly well maintained;
but, at the first suspicion of an Ant-hill, the vanguard halts and
deploys in a swarming throng, which is increased by the others as they
come up hurriedly. Scouts are sent out; the Amazons recognize that
they are on a wrong track; and the column forms again. It resumes its
march, crosses the garden-paths, disappears from sight in the grass,
reappears farther on, threads its way through the heaps of dead
leaves, comes out again and continues its search. At last, a nest of
Black Ants is discovered. The Red Ants hasten down to the dormitories
where the nymphs lie and soon emerge with their booty. Then we have,
at the gates of the underground city, a bewildering scrimmage between
the defending blacks and the attacking reds. The struggle is too
unequal to remain indecisive. Victory falls to the reds, who race back
to their abode, each with her prize, a swaddled nymph, dangling from
her mandibles. The reader who is not acquainted with these slave-
raiding habits would be greatly interested in the story of the
Amazons. I relinquish it, with much regret: it would take us too far
from our subject, namely, the return to the nest.
The distance covered by the nymph-stealing column varies: it all
depends on whether Black Ants are plentiful in the neighbourhood. At
times, ten or twenty yards suffice; at others, it requires fifty, a
hundred or more. I once saw the expedition go beyond the garden. The
Amazons scaled the surrounding wall, which was thirteen feet high at
that point, climbed over it and went on a little farther, into a
cornfield. As for the route taken, this is a matter of indifference to
the marching column. Bare ground, thick grass, a heap of dead leaves
or stones, brickwork, a clump of shrubs: all are crossed without any
marked preference for one sort of road rather than another.
What is rigidly fixed is the path home, which follows the outward
track in all its windings and all its crossings, however difficult.
Laden with their plunder, the Red Ants return to the nest by the same
road, often an exceedingly complicated one, which the exigencies of
the chase compelled them to take originally. They repass each spot
which they passed at first; and this is to them a matter of such
imperative necessity that no additional fatigue nor even the gravest
danger can make them alter the track.
Let us suppose that they have crossed a thick heap of dead leaves,
representing to them a path beset with yawning gulfs, where every
moment some one falls, where many are exhausted as they struggle out
of the hollows and reach the heights by means of swaying bridges,
emerging at last from the labyrinth of lanes. No matter: on their
return, they will not fail, though weighed down with their burden,
once more to struggle through that weary maze. To avoid all this
fatigue, they would have but to swerve slightly from the original
path, for the good, smooth road is there, hardly a step away. This
little deviation never occurs to them.
I came upon them one day when they were on one of their raids. They
were marching along the inner edge of the stone-work of the garden-
pond, where I have replaced the old batrachians by a colony of Gold-
fish. The wind was blowing very hard from the north and, taking the
column in flank, sent whole rows of the Ants flying into the water.
The fish hurried up; they watched the performance and gobbled up the
drowning insects. It was a difficult bit; and the column was decimated
before it had passed. I expected to see the return journey made by
another road, which would wind round and avoid the fatal cliff. Not at
all. The nymph-laden band resumed the parlous path and the Goldfish
received a double windfall: the Ants and their prizes. Rather than
alter its track, the column was decimated a second time.
It is not easy to find the way home again after a distant expedition,
during which there have been various sorties, nearly always by
different paths; and this difficulty makes it absolutely necessary for
the Amazons to return by the same road by which they went. The insect
has no choice of route, if it would not be lost on the way: it must
come back by the track which it knows and which it has lately
travelled. The Processionary Caterpillars, when they leave their nest
and go to another branch, on another tree, in search of a type of leaf
more to their taste, carpet the course with silk and are able to
return home by following the threads stretched along their road. This
is the most elementary method open to the insect liable to stray on
its excursions: a silken path brings it home again. The
Processionaries, with their unsophisticated traffic-laws, are very
different from the Mason-bees and others, who have a special sense to
guide them.
The Amazon, though belonging to the Hymenopteron clan, herself
possesses rather limited homing-faculties, as witness her compulsory
return by her former trail. Can she imitate, to a certain extent, the
Processionaries' method, that is to say, does she leave, along the
road traversed, not a series of conducting threads, for she is not
equipped for that work, but some odorous emanation, for instance some
formic scent, which would allow her to guide herself by means of the
olfactory sense? This view is pretty generally accepted. The Ants,
people say, are guided by the sense of smell; and this sense of smell
appears to have its seat in the antennae, which we see in continual
palpitation. It is doubtless very reprehensible, but I must admit that
the theory does not inspire me with overwhelming enthusiasm. In the
first place, I have my suspicions about a sense of smell seated in the
antennae: I have given my reasons before; and, next, I hope to prove
by experiment that the Red Ants are not guided by a scent of any kind.
To lie in wait for my Amazons, for whole afternoons on end, often
unsuccessfully, meant taking up too much of my time. I engaged an
assistant whose hours were not so much occupied as mine. It was my
grand-daughter Lucie, a little rogue who liked to hear my stories of
the Ants. She had been present at the great battle between the reds
and blacks and was much impressed by the rape of the long-clothes
babies. Well-coached in her exalted functions, very proud of already
serving that august lady, Science, my little Lucie would wander about
the garden, when the weather seemed propitious, and keep an eye on the
Red Ants, having been commissioned to reconnoitre carefully the road
to the pillaged Ant-hill. She had given proof of her zeal; I could
rely upon it.
One day, while I was spinning out my daily quota of prose, there came
a banging at my study-door:
'It's I, Lucie! Come quick: the reds have gone into the blacks' house.
Come quick!'
'And do you know the road they took?'
'Yes, I marked it.'
'What! Marked it? How?'
'I did what Hop-o'-my-Thumb did: I scattered little white stones along
the road.'
I hurried out. Things had happened as my six-year-old colleague said.
Lucie had secured her provision of pebbles in advance and, on seeing
the Amazon regiment leave barracks, had followed them step by step and
placed her stones at intervals along the road covered. The Ants had
made their raid and were beginning to return along the track of tell-
tale pebbles. The distance to the nest was about a hundred paces,
which gave me time to make preparations for an experiment previously
contemplated.
I take a big broom and sweep the track for about a yard across. The
dusty particles on the surface are thus removed and replaced by
others. If they were tainted with any odorous effluvia, their absence
will throw the Ants off the track. I divide the road, in this way, at
four different points, a few feet a part.
The column arrives at the first section. The hesitation of the Ants is
evident. Some recede and then return, only to recede once more; others
wander along the edge of the cutting; others disperse sideways and
seem to be trying to skirt the unknown country. The head of the
column, at first closed up to a width of a foot or so, now scatters to
three or four yards. But fresh arrivals gather in their numbers before
the obstacle; they form a mighty array, an undecided horde. At last, a
few Ants venture into the swept zone and others follow, while a few
have meantime gone ahead and recovered the track by a circuitous
route. At the other cuttings, there are the same halts, the same
hesitations; nevertheless, they are crossed, either in a straight line
or by going round. In spite of my snares, the Ants manage to return to
the nest; and that by way of the little stones.
The result of the experiment seems to argue in favour of the sense of
smell. Four times over, there are manifest hesitations wherever the
road is swept. Though the return takes place, nevertheless, along the
original track, this may be due to the uneven work of the broom, which
has left certain particles of the scented dust in position. The Ants
who went round the cleared portion may have been guided by the
sweepings removed to either side. Before, therefore, pronouncing
judgment for or against the sense of smell, it were well to renew the
experiment under better conditions and to remove everything containing
a vestige of scent.
A few days later, when I have definitely decided on my plan, Lucie
resumes her watch and soon comes to tell me of a sortie. I was
counting on it, for the Amazons rarely miss an expedition during the
hot and sultry afternoons of June and July, especially when the
weather threatens storm. Hop-o'-my-Thumb's pebbles once more mark out
the road, on which I choose the point best-suited to my schemes.
A garden-hose is fixed to one of the feeders of the pond; the sluice
is opened; and the Ants' path is cut by a continuous torrent, two or
three feet wide and of unlimited length. The sheet of water flows
swiftly and plentifully at first, so as to wash the ground well and
remove anything that may possess a scent. This thorough washing lasts
for nearly a quarter of an hour. Then, when the Ants draw near,
returning from the plunder, I let the water flow more slowly and
reduce its depth, so as not to overtax the strength of the insects.
Now we have an obstacle which the Amazons must surmount, if it is
absolutely necessary for them to follow the first trail.
This time, the hesitation lasts long and the stragglers have time to
come up with the head of the column. Nevertheless, an attempt is made
to cross the torrent by means of a few bits of gravel projecting above
the water; then, failing to find bottom, the more reckless of the Ants
are swept off their feet and, without loosing hold of their prizes,
drift away, land on some shoal, regain the bank and renew their search
for a ford. A few straws borne on the waters stop and become so many
shaky bridges on which the Ants climb. Dry olive-leaves are converted
into rafts, each with its load of passengers. The more venturesome,
partly by their own efforts, partly by good luck, reach the opposite
bank without adventitious aid. I see some who, dragged by the current
to one or the other bank, two or three yards off, seem very much
concerned as to what they shall do next. Amid this disorder, amid the
dangers of drowning, not one lets go her booty. She would not dream of
doing so: death sooner than that! In a word, the torrent is crossed
somehow or other along the regular track.
The scent of the road cannot be the cause of this, it seems to me, for
the torrent not only washed the ground some time beforehand but also
pours fresh water on it all the time that the crossing is taking
place. Let us now see what will happen when the formic scent, if there
really be one on the trail, is replaced by another, much stronger
odour, one perceptible to our own sense of smell, which the first is
not, at least not under present conditions.
I wait for a third sortie and, at one point in the road taken by the
Ants, rub the ground with some handfuls of freshly gathered mint. I
cover the track, a little farther on, with the leaves of the same
plant. The Ants, on their return, cross the section over which the
mint was rubbed without apparently giving it a thought; they hesitate
in front of the section heaped up with leaves and then go straight on.
After these two experiments, first with the torrent of water which
washes away all traces of smell from the ground and then with the mint
which changes the smell, I think that we are no longer at liberty to
quote scent as the guide of the Ants that return to the nest by the
road which they took at starting. Further tests will tell us more
about it.
Without interfering with the soil, I now lay across the track some
large sheets of paper, newspapers, keeping them in position with a few
small stones. In front of this carpet, which completely alters the
appearance of the road, without removing any sort of scent that it may
possess, the Ants hesitate even longer than before any of my other
snares, including the torrent. They are compelled to make manifold
attempts, reconnaissances to right and left, forward movements and
repeated retreats, before venturing altogether into the unknown zone.
The paper straits are crossed at last and the march resumed as usual.
Another ambush awaits the Amazons some distance farther on. I have
divided the track by a thin layer of yellow sand, the ground itself
being grey. This change of colour alone is enough for a moment to
disconcert the Ants, who again hesitate in the same way, though not
for so long, as they did before the paper. Eventually, this obstacle
is overcome like the others.
As neither the stretch of sand nor the stretch of paper got rid of any
scented effluvia with which the trail may have been impregnated, it is
patent that, as the Ants hesitated and stopped in the same way as
before, they find their way not by sense of smell, but really and
truly by sense of sight; for, every time that I alter the appearance
of the track in any way whatever--whether by my destructive broom, my
streaming water, my green mint, my paper carpet or my golden sand--the
returning column calls a halt, hesitates and attempts to account for
the changes that have taken place. Yes, it is sight, but a very dull
sight, whose horizon is altered by the shifting of a few bits of
gravel. To this short sight, a strip of paper, a bed of mint-leaves, a
layer of yellow sand, a stream of water, a furrow made by the broom,
or even lesser modifications are enough to transform the landscape;
and the regiment, eager to reach home as fast as it can with its loot,
halts uneasily on beholding this unfamiliar scenery. If the doubtful
zones are at length passed, it is due to the fact that fresh attempts
are constantly being made to cross the doctored strips and that at
last a few Ants recognize well-known spots beyond them. The others,
relying on their clearer-sighted sisters, follow.
Sight would not be enough, if the Amazon had not also at her service a
correct memory for places. The memory of an Ant! What can that be? In
what does it resemble ours? I have no answers to these questions; but
a few words will enable me to prove that the insect has a very exact
and persistent recollection of places which it has once visited. Here
is something which I have often witnessed. It sometimes happens that
the plundered Ant-hill offers the Amazons a richer spoil than the
invading column is able to carry away. Or, again, the region visited
is rich in Ant-hills. Another raid is necessary, to exploit the site
thoroughly. In such cases, a second expedition takes place, sometimes
on the next day, sometimes two or three days later. This time, the
column does no reconnoitring on the way: it goes straight to the spot
known to abound in nymphs and travels by the identical path which it
followed before. It has sometimes happened that I have marked with
small stones, for a distance of twenty yards, the road pursued a
couple of days earlier and have then found the Amazons proceeding by
the same route, stone by stone:
'They will go first here and then there,' I said, according to the
position of the guide-stones.
And they would, in fact, go first here and then there, skirting my
line of pebbles, without any noticeable deviation.
Can one believe that odoriferous emanations diffused along the route
are going to last for several days? No one would dare to suggest it.
It must, therefore, be sight that directs the Amazons, sight assisted
by a memory for places. And this memory is tenacious enough to retain
the impression until the next day and later; it is scrupulously
faithful, for it guides the column by the same path as on the day
before, across the thousand irregularities of the ground.
How will the Amazon behave when the locality is unknown to her? Apart
from topographical memory, which cannot serve her here, the region in
which I imagine her being still unexplored, does the Ant possess the
Mason-bee's sense of direction, at least within modest limits, and is
she able thus to regain her Ant-hill or her marching column?
The different parts of the garden are not all visited by the marauding
legions to the same extent: the north side is exploited by preference,
doubtless because the forays in that direction are more productive.
The Amazons, therefore, generally direct their troops north of their
barracks; I seldom see them in the south. This part of the garden is,
if not wholly unknown, at least much less familiar to them than the
other. Having said that, let us observe the conduct of the strayed
Ant.
I take up my position near the Ant-hill; and, when the column returns
from the slave-raid, I force an Ant to step on a leaf which I hold out
to her. Without touching her, I carry her two or three paces away from
her regiment: no more than that, but in a southerly direction. It is
enough to put her astray, to make her lose her bearings entirely. I
see the Amazon, now replaced on the ground, wander about at random,
still, I need hardly say, with her booty in her mandibles; I see her
hurry away from her comrades, thinking that she is rejoining them; I
see her retrace her steps, turn aside again, try to the right, try to
the left and grope in a host of directions, without succeeding in
finding her whereabouts. The pugnacious, strong-jawed slave-hunter is
utterly lost two steps away from her party. I have in mind certain
strays who, after half an hour's searching, had not succeeded in
recovering the route and were going farther and farther from it, still
carrying the nymph in their teeth. What became of them? What did they
do with their spoil? I had not the patience to follow those dull-
witted marauders to the end.
Let us repeat the experiment, but place the Amazon to the north. After
more or less prolonged hesitations, after a search now in this
direction, now in that, the Ant succeeds in finding her column. She
knows the locality.
Here, of a surety, is a Hymenopteron deprived of that sense of
direction which other Hymenoptera enjoy. She has in her favour a
memory for places and nothing more. A deviation amounting to two or
three of our strides is enough to make her lose her way and to keep
her from returning to her people, whereas miles across unknown country
will not foil the Mason-bee. I expressed my surprise, just now, that
man was deprived of a wonderful sense wherewith certain animals are
endowed. The enormous distance between the two things compared might
furnish matter for discussion. In the present case, the distance no
longer exists: we have to do with two insects very near akin, two
Hymenoptera. Why, if they issue from the same mould, has one a sense
which the other has not, an additional sense, constituting a much more
overpowering factor than the structural details? I will wait until the
evolutionists condescend to give me a valid reason.
To return to this memory for places whose tenacity and fidelity I have
just recognized: to what degree does it consent to retain impressions?
Does the Amazon require repeated journeys in order to learn her
geography, or is a single expedition enough for her? Are the line
followed and the places visited engraved on her memory from the first?
The Red Ant does not lend herself to the tests that might furnish the
reply: the experimenter is unable to decide whether the path followed
by the expeditionary column is being covered for the first time, nor
is it in his power to compel the legion to adopt this or that
different road. When the Amazons go out to plunder the Ant-hills, they
take the direction which they please; and we are not allowed to
interfere with their march. Let us turn to other Hymenoptera for
information.
I select the Pompili, whose habits we shall study in detail in a later
chapter. (For the Wasp known as the Pompilus, or Ringed Calicurgus,
cf. "The Life and Love of the Insect", by J. Henri Fabre, translated
by Alexander Teixeira de Mattos: chapter 12.--Translator's Note.) They
are hunters of Spiders and diggers of burrows. The game, the food of
the coming larva, is first caught and paralysed; the home is excavated
afterwards. As the heavy prey would be a grave encumbrance to the Wasp
in search of a convenient site, the Spider is placed high up, on a
tuft of grass or brushwood, out of the reach of marauders, especially
Ants, who might damage the precious morsel in the lawful owner's
absence. After fixing her booty on the verdant pinnacle, the Pompilus
casts around for a favourable spot and digs her burrow. During the
process of excavation, she returns from time to time to her Spider;
she nibbles at the prize, feels, touches it here and there, as though
taking stock of its plumpness and congratulating herself on the
plentiful provender; then she returns to her burrow and goes on
digging. Should anything alarm or distress her, she does not merely
inspect her Spider: she also brings her a little closer to her work-
yard, but never fails to lay her on the top of a tuft of verdure.
These are the manoeuvres of which I can avail myself to gauge the
elasticity of the Wasp's memory.
While the Pompilus is at work on the burrow, I seize the prey and
place it in an exposed spot, half a yard away from its original
position. The Pompilus soon leaves the hole to enquire after her booty
and goes straight to the spot where she left it. This sureness of
direction, this faithful memory for places can be explained by
repeated previous visits. I know nothing of what has happened
beforehand. Let us take no notice of this first expedition; the others
will be more conclusive. For the moment, the Pompilus, without the
least hesitation, finds the tuft of grass whereon her prey was lying.
Then come marches and counter-marches upon that tuft, minute
explorations and frequent returns to the exact spot where the Spider
was deposited. At last, convinced that the prize is no longer there,
the Wasp makes a leisurely survey of the neighbourhood, feeling the
ground with her antennae as she goes. The Spider is descried in the
exposed spot where I had placed her. Surprise on the part of the
Pompilus, who goes forward and then suddenly steps back with a start:
'Is it alive?' she seems to ask. 'Is it dead? Is it really my Spider?
Let us be wary!'
The hesitation does not last long: the huntress grabs her victim,
drags her backwards and places her, still high up, on a second tuft of
herbage, two or three steps away from the first. She then goes back to
the burrow and digs for a while. For the second time, I remove the
Spider and lay her at some distance, on the bare ground. This is the
moment to judge of the Wasp's memory. Two tufts of grass have served
as temporary resting-places for the game. The first, to which she
returned with such precision, the Wasp may have learnt to know by a
more or less thorough examination, by reiterated visits that escaped
my eye; but the second has certainly made but a slight impression on
her memory. She adopted it without any studied choice; she stopped
there just long enough to hoist her Spider to the top; she saw it for
the first time and saw it hurriedly, in passing. Is that rapid glance
enough to provide an exact recollection? Besides, there are now two
localities to be modelled in the insect's memory: the first shelf may
easily be confused with the second. To which will the Pompilus go?
We shall soon find out: here she comes, leaving the burrow to pay a
fresh visit to the Spider. She runs straight to the second tuft, where
she hunts about for a long time for her absent prey. She knows that it
was there, when last seen, and not elsewhere; she persists in looking
for it there and does not once think of going back to the first perch.
The first tuft of grass no longer counts; the second alone interests
her. And then the search in the neighbourhood begins again.
On finding her game on the bare spot where I myself have placed it,
the Pompilus quickly deposits the Spider on a third tuft of grass; and
the experiment is renewed. This time, the Pompilus hurries to the
third tuft when she comes to look after her Spider; she hurries to it
without hesitation, without confusing it in any way with the first
two, which she scorns to visit, so sure is her memory. I do the same
thing a couple of times more; and the insect always returns to the
last perch, without worrying about the others. I stand amazed at the
memory of that pigmy. She need but catch a single hurried glimpse of a
spot that differs in no wise from a host of others in order to
remember it quite well, notwithstanding the fact that, as a miner
relentlessly pursuing her underground labours, she has other matters
to occupy her mind. Could our own memory always vie with hers? It is
very doubtful. Allow the Red Ant the same sort of memory; and her
peregrinations, her returns to the nest by the same road are no longer
difficult to explain.
Tests of this kind have furnished me with some other results worthy of
mention. When convinced, by untiring explorations, that her prey is no
longer on the tuft where she laid it, the Pompilus, as we were saying,
looks for it in the neighbourhood and finds it pretty easily, for I am
careful to put it in an exposed place. Let us increase the difficulty
to some extent. I dig the tip of my finger into the ground and lay the
Spider in the little hole thus obtained, covering her with a tiny
leaf. Now the Wasp, while in quest of her lost prey, happens to walk
over this leaf, to pass it again and again without suspecting that the
Spider lies beneath, for she goes and continues her vain search
farther off. Her guide, therefore is not scent, but sight.
Nevertheless, she is constantly feeling the ground with her antennae.
What can be the function of those organs? I do not know, although I
assert that they are not olfactory organs. The Ammophila, in search of
her Grey Worm, had already led me to make the same assertion; I now
obtain an experimental proof which seems to me decisive. I would add
that the Pompilus has very short sight: often she passes within a
couple of inches of her Spider without seeing her.
CHAPTER 7. SOME REFLECTIONS UPON INSECT PSYCHOLOGY.
The laudator temperis acti is out of favour just now: the world is on
the move. Yes, but sometimes it moves backwards. When I was a boy, our
twopenny textbooks told us that man was a reasoning animal; nowadays,
there are learned volumes to prove to us that human reason is but a
higher rung in the ladder whose foot reaches down to the bottommost
depths of animal life. There is the greater and the lesser; there are
all the intermediary rounds; but nowhere does it break off and start
afresh. It begins with zero in the glair of a cell and ascends until
we come to the mighty brain of a Newton. The noble faculty of which we
were so proud is a zoological attribute. All have a larger or smaller
share of it, from the live atom to the anthropoid ape, that hideous
caricature of man.
It always struck me that those who held this levelling theory made
facts say more than they really meant; it struck me that, in order to
obtain their plain, they were lowering the mountain-peak, man, and
elevating the valley, the animal. Now this levelling of theirs needed
proofs, to my mind; and, as I found none in their books, or at any
rate only doubtful and highly debatable ones, I did my own observing,
in order to arrive at a definite conviction; I sought; I experimented.
To speak with any certainty, it behoves us not to go beyond what we
really know. I am beginning to have a passable acquaintance with
insects, after spending some forty years in their company. Let us
question the insect, then: not the first that comes along, but the
most gifted, the Hymenopteron. I am giving my opponents every
advantage. Where will they find a creature more richly endowed with
talent? It would seem as though, in creating it, nature had delighted
in bestowing the greatest amount of industry upon the smallest body of
matter. Can the bird, wonderful architect that it is, compare its work
with that masterpiece of higher geometry, the edifice of the Bee? The
Hymenopteron rivals man himself. We build towns, the Bee erects
cities; we have servants, the Ant has hers; we rear domestic animals,
she rears her sugar-yielding insects; we herd cattle, she herds her
milch-cows, the Aphides; we have abolished slavery, whereas she
continues her nigger-traffic.
Well, does this superior, this privileged being reason? Reader, do not
smile: this is a most serious matter, well worthy of our
consideration. To devote our attention to animals is to plunge at once
into the vexed question of who we are and whence we come. What, then,
passes in that little Hymenopteron brain? Has it faculties akin to
ours, has it the power of thought? What a problem, if we could only
solve it; what a chapter of psychology, if we could only write it!
But, at our very first questionings, the mysterious will rise up,
impenetrable: we may be convinced of that. We are incapable of knowing
ourselves; what will it be if we try to fathom the intellect of
others? Let us be content if we succeed in gleaning a few grains of
truth.
What is reason? Philosophy would give us learned definitions. Let us
be modest and keep to the simplest: we are only treating of animals.
Reason is the faculty that connects the effect with its cause and
directs the act by conforming it to the needs of the accidental.
Within these limits, are animals capable of reasoning? Are they able
to connect a 'because' with a 'why' and afterwards to regulate their
behaviour accordingly? Are they able to change their line of conduct
when faced with an emergency?
History has but few data likely to be of use to us here; and those
which we find scattered in various authors are seldom able to
withstand a severe examination. One of the most remarkable of which I
know is supplied by Erasmus Darwin, in his book entitled "Zoonomia."
It tells of a Wasp that has just caught and killed a big Fly. The wind
is blowing; and the huntress, hampered in her flight by the great area
presented by her prize, alights on the ground to amputate the abdomen,
the head and the wings; she flies away, carrying with her only the
thorax, which gives less hold to the wind. If we keep to the bald
facts, this does, I admit, give a semblance of reason. The Wasp
appears to grasp the relation between cause and effect. The effect is
the resistance experienced in the flight; the cause is the dimensions
of the prey contending with the air. Hence the logical conclusion:
those dimensions must be lessened; the abdomen, the head and, above
all, the wings must be chopped off; and the resistance will be
decreased. (I would gladly, if I were able, cancel some rather hasty
lines which I allowed myself to pen in the first volume of these
"Souvenirs" but scripta manent. All that I can do is to make amends
now, in this note, for the error into which I fell. Relying on
Lacordaire, who quotes this instance from Erasmus Darwin in his own
"Introduction a l'entomologie", I believed that a Sphex was given as
the heroine of the story. How could I do otherwise, not having the
original text in front of me? How could I suspect that an entomologist
of Lacordaire's standing should be capable of such a blunder as to
substitute a Sphex for a Common Wasp? Great was my perplexity, in the
face of this evidence! A Sphex capturing a Fly was an impossibility;
and I blamed the British scientist accordingly. But what insect was it
that Erasmus Darwin saw? Calling logic to my aid, I declared that it
was a Wasp; and I could not have hit the mark more truly. Charles
Darwin, in fact, informed me afterwards that his grandfather wrote 'a
Wasp' in his "Zoonomia." Though the correction did credit to my
intelligence, I none the less deeply regretted my mistake, for I had
uttered suspicions of the observer's powers of discernment, unjust
suspicions which the translator's inaccuracy led me into entertaining.
May this note serve to mitigate the harshness of the strictures
provoked by my overtaxed credulity! I do not scruple to attack ideas
which I consider false; but Heaven forfend that I should ever attack
those who uphold them!--Author's Note.)
But does this concatenation of ideas, rudimentary though it be, really
take place within the insect's brain? I am convinced of the contrary;
and my proofs are unanswerable. In the first volume of these
"Souvenirs" (Cf. "Insect Life": chapter 9.--Translator's Note.), I
demonstrated by experiment that Erasmus Darwin's Wasp was but obeying
her instinct, which is to cut up the captured game and to keep only
the most nourishing part, the thorax. Whether the day be perfectly
calm or whether the wind blow, whether she be in the shelter of a
dense thicket or in the open, I see the Wasp proceed to separate the
succulent from the tough; I see her reject the legs, the wings, the
head and the abdomen, retaining only the breast as pap for her larvae.
Then what value has this dissection as an argument in favour of the
insect's reasoning-powers when the wind blows? It has no value at all,
for it would take place just the same in absolutely calm weather.
Erasmus Darwin jumped too quickly to his conclusion, which was the
outcome of his mental bias and not of the logic of things. If he had
first enquired into the Wasp's habits, he would not have brought
forward as a serious argument an incident which had no connection with
the important question of animal reason.
I have reverted to this case to show the difficulties that beset the
man who confines himself to casual observations, however carefully
carried out. One should never rely upon a lucky chance, which may not
occur again. We must multiply our observations, check them one with
the other; we must create incidents, looking into preceding ones,
finding out succeeding ones and working out the relation between them
all: then and not till then, with extreme caution, are we entitled to
express a few views worthy of credence. Nowhere do I find data
collected under such conditions; for which reason, however much I
might wish it, it is impossible for me to bring the evidence of others
in support of the few conclusions which I myself have formed.
My Mason-bees, with their nests hanging on the walls of the arch which
I have mentioned, lent themselves to continuous experiment better than
any other Hymenopteron. I had them there, at my house, under my eyes,
at all hours of the day, as long as I wished. I was free to follow
their actions in full detail and to carry out successfully any
experiment, however long. Moreover, their numbers allowed me to repeat
my attempts until I was perfectly convinced. The Mason-bees,
therefore, shall supply me with the materials for this chapter also.
A few words, before I begin, about the works. The Mason-bee of the
Sheds utilizes, first of all, the old galleries of the clay nest, a
part of which she good-naturedly abandons to two Osmiae, her free
tenants: the Three-horned Osmia and Latreille's Osmia. These old
corridors, which save labour, are in great demand; but there are not
many vacant, as the more precocious Osmiae have already taken
possession of most of them; and therefore the building of new cells
soon begins. These cells are cemented to the surface of the nest,
which thus increases in thickness every year. The edifice of cells is
not built all at once: mortar and honey alternate repeatedly. The
masonry starts with a sort of little swallow's nest, a half-cup or
thimble, whose circumference is completed by the wall against which it
rests. Picture the cup of an acorn cut in two and stuck to the surface
of the nest: there you have the receptacle in a stage sufficiently
advanced to take a first instalment of honey.
The Bee thereupon leaves the mortar and busies herself with
harvesting. After a few foraging-trips, the work of building is
resumed; and some new rows of bricks raise the edge of the basin,
which becomes capable of receiving a larger stock of provisions. Then
comes another change of business: the mason once more becomes a
harvester. A little later, the harvester is again a mason; and these
alternations continue until the cell is of the regulation height and
holds the amount of honey required for the larva's food. Thus come,
turn and turn about, more or less numerous according to the occupation
in hand, journeys to the dry and barren path, where the cement is
gathered and mixed, and journeys to the flowers, where the Bee's crop
is crammed with honey and her belly powdered with pollen.
At last comes the time for laying. We see the Bee arrive with a pellet
of mortar. She gives a glance at the cell to enquire if everything is
in order; she inserts her abdomen; and the egg is laid. Then and there
the mother seals up the home: with her pellet of cement she closes the
orifice and manages so well with the material that the lid receives
its permanent form at this first sitting; it has only to be thickened
and strengthened with fresh layers, a work which is less urgent and
will be done by and by. What does appear to be an urgent necessity is
the closing of the cell immediately after the egg has been religiously
deposited therein, so that there may be no danger from evilly-disposed
visitors during the mother's absence. The Bee must have serious
reasons for thus hurrying on the closing of the cell. What would
happen if, after laying her egg, she left the house open and went to
the cement-pit to fetch the wherewithal to block the door? Some thief
might drop in and substitute her own egg for the Mason-bee's. We shall
see that our suspicions are not uncalled-for. One thing is certain,
that the Mason never lays without having in her mandibles the pellet
of mortar required for the immediate construction of the lid of the
nest. The precious egg must not for a single instant remain exposed to
the cupidity of marauders.
To these particulars I will add a few general observations which will
make what follows easier to understand. So long as its circumstances
are normal, the insect's actions are calculated most rationally in
view of the object to be attained. What could be more logical, for
instance, than the devices employed by the Hunting Wasp when
paralysing her prey (Cf. "Insect Life": chapters 3 to 12 and 15 to
17.--Translator's Note.) so that it may keep fresh for her larva,
while in no wise imperilling that larva's safety? It is preeminently
rational; we ourselves could think of nothing better; and yet the
Wasp's action is not prompted by reason. If she thought out her
surgery, she would be our superior. It will never occur to anybody
that the creature is able, in the smallest degree, to account for its
skilful vivisections. Therefore, so long as it does not depart from
the path mapped out for it, the insect can perform the most sagacious
actions without entitling us in the least to attribute these to the
dictates of reason.
What would happen in an emergency? Here we must distinguish carefully
between two classes of emergency, or we shall be liable to grievous
error. First, in accidents occurring in the course of the insect's
occupation at the moment. In these circumstances, the creature is
capable of remedying the accident; it continues, under a similar form,
its actual task; it remains, in short; in the same psychic condition.
In the second case, the accident is connected with a more remote
occupation; it relates to a completed task with which, under normal
conditions, the insect is no longer concerned. To meet this emergency,
the creature would have to retrace its psychic course; it would have
to do all over again what it has just finished, before turning its
attention to anything else. Is the insect capable of this? Will it be
able to leave the present and return to the past? Will it decide to
hark back to a task that is much more pressing than the one on which
it was engaged? If it did all this, then we should really have
evidence of a modicum of reason. The question shall be settled by
experiment.
We will begin by taking a few incidents that come under the first
heading. A Mason-bee has finished the initial layer of the covering of
the cell. She has gone in search of a second pellet of mortar
wherewith to strengthen her work. In her absence, I prick the lid with
a needle and widen the hole thus made, until it is half the size of
the opening. The insect returns and repairs the damage. It was
originally engaged on the lid and is merely continuing its work in
mending that lid.
A second is still at her first row of bricks. The cell as yet is no
more than a shallow cup, containing no provisions. I make a big hole
in the bottom of the cup and the Bee hastens to stop the breach. She
was busy building and turned aside a moment to do more building. Her
repairs are the continuation of the work on which she was engaged.
A third has laid her egg and closed the cell. While she is gone in
search of a fresh supply of cement to strengthen the door, I make a
large aperture immediately below the lid, too high up to allow the
honey to escape. The insect, on arriving with its mortar intended for
a different task, sees its broken jar and soon puts the damage right.
I have rarely witnessed such a sensible performance. Nevertheless, all
things considered, let us not be too lavish of our praises. The insect
was busy closing up. On its return, it sees a crack, representing in
its eyes a bad join which it had overlooked; it completes its actual
task by improving the join.
The conclusion to be drawn from these three instances, which I select
from a large number of others, more or less similar, is that the
insect is able to cope with emergencies, provided that the new action
be not outside the course of its actual work at the moment. Shall we
say then that reason directs it? Why should we? The insect persists in
the same psychic course, it continues its action, it does what it was
doing before, it corrects what to it appears but a careless flaw in
the work of the moment.
Here, moreover, is something which would change our estimate entirely,
if it ever occurred to us to look upon these repaired breaches as a
work dictated by reason. Let us turn to the second class of emergency
referred to above: let us imagine, first, cells similar to those in
the second experiment, that is to say, only half-finished, in the form
of a shallow cup, but already containing honey. I make a hole in the
bottom, through which the provisions ooze and run to waste. Their
owners are harvesting. Let us imagine, on the other hand, cells very
nearly finished and almost completely provisioned. I perforate the
bottom in the same way and let out the honey, which drips through
gradually. The owners of these are building.
Judging by what has gone before, the reader will perhaps expect to see
immediate repairs, urgent repairs, for the safety of the future larva
is at stake. Let him dismiss any such illusion: more and more journeys
are undertaken, now in quest of food, now in quest of mortar; but not
one of the Mason-bees troubles about the disastrous breach. The
harvester goes on harvesting; the busy bricklayer proceeds with her
next row of bricks, as though nothing out of the way had happened.
Lastly, if the injured cells are high enough and contain enough
provisions, the Bee lays her eggs, puts a door to the house and passes
on to another house, without doing aught to remedy the leakage of the
honey. Two or three days later, those cells have lost all their
contents, which now form a long trail on the surface of the nest.
Is it through lack of intelligence that the Bee allows her honey to go
to waste? May it not rather be through helplessness? It might happen
that the sort of mortar which the Mason has at her disposal will not
set on the edges of a hole that is sticky with honey. The honey may
prevent the cement from adjusting itself to the orifice, in which case
the insect's inertness would merely be resignation to an irreparable
evil. Let us look into the matter before drawing inferences. With my
forceps, I deprive the Bee of her pellet of mortar and apply it to the
hole whence the honey is escaping. My attempt at repairing meets with
the fullest success, though I do not pretend to compete with the Mason
in dexterity. For a piece of work done by a man's hand it is quite
creditable. My dab of mortar fits nicely into the mutilated wall; it
hardens as usual; and the escape of honey ceases. This is quite
satisfactory. What would it be had the work been done by the insect,
equipped with its tools of exquisite precision? When the Mason-bee
refrains, therefore, this is not due to helplessness on her part, nor
to any defect in the material employed.
Another objection presents itself. We are going too far perhaps in
admitting this concatenation of ideas in the insect's mind, in
expecting it to argue that the honey is running away because the cell
has a hole in it and that to save it from being wasted the hole must
be stopped. So much logic perhaps exceeds the powers of its poor
little brain. Then, again, the hole is not seen; it is hidden by the
honey trickling through. The cause of that stream of honey is an
unknown cause; and to trace the loss of the liquid home to that cause,
to the hole in the receptacle, is too lofty a piece of reasoning for
the insect.
A cell in the rudimentary cup-stage and containing no provisions has a
hole, three or four millimetres (.11 to .15 inch.--Translator's Note.)
wide, made in it at the bottom. A few moments later, this orifice is
stopped by the Mason. We have already witnessed a similar patching.
The insect, having finished, starts foraging. I reopen the hole at the
same place. The pollen runs through the aperture and falls to the
ground as the Bee is rubbing off her first load in the cell. The
damage is undoubtedly observed. When plunging her head into the cup to
take stock of what she has stored, the Bee puts her antennae into the
artificial hole: she sounds it, she explores it, she cannot fail to
perceive it.
I see the two feelers quivering outside the hole. The insect notices
the breach in the wall: that is certain. It flies off. Will it bring
back mortar from its present journey to repair the injured jar as it
did just now?
Not at all. It returns with provisions, it disgorges its honey, it
rubs off its pollen, it mixes the material. The sticky and almost
solid mass fills up the opening and oozes through with difficulty. I
roll a spill of paper and free the hole, which remains open and shows
daylight distinctly in both directions. I sweep the place clear over
and over again, whenever this becomes necessary because new provisions
are brought; I clean the opening sometimes in the Bee's absence,
sometimes in her presence, while she is busy mixing her paste. The
unusual happenings in the warehouse plundered from below cannot escape
her any more than the ever-open breach at the bottom of the cell.
Nevertheless, for three consecutive hours, I witness this strange
sight: the Bee, full of active zeal for the task in hand, omits to
plug this vessel of the Danaides. She persists in trying to fill her
cracked receptacle, whence the provisions disappear as soon as stored
away. She constantly alternates between builder's and harvester's
work; she raises the edges of the cell with fresh rows of bricks; she
brings provisions which I continue to abstract, so as to leave the
breach always visible. She makes thirty-two journeys before my eyes,
now for mortar, now for honey, and not once does she bethink herself
of stopping the leakage at the bottom of her jar.
At five o'clock in the evening, the works cease. They are resumed on
the morrow. This time, I neglect to clean out my artificial orifice
and leave the victuals gradually to ooze out by themselves. At length,
the egg is laid and the door sealed up, without anything being done by
the Bee in the matter of the disastrous breach. And yet to plug the
hole were an easy matter for her: a pellet of her mortar would
suffice. Besides, while the cup was still empty, did she not instantly
close the hole which I had made? Why are not those early repairs of
hers repeated? It clearly shows the creature's inability to retrace
the course of its actions, however slightly. At the time of the first
breach, the cup was empty and the insect was laying the first rows of
bricks. The accident produced through my agency concerned the part of
the work which occupied the Bee at the actual moment; it was a flaw in
the building, such as can occur naturally in new courses of masonry,
which have not had time to harden. In correcting that flaw, the Mason
did not go outside her usual work.
But, once the provisioning begins, the cup is finished for good and
all; and, come what may, the insect will not touch it again. The
harvester will go on harvesting, though the pollen trickle to the
ground through the drain. To plug the hole would imply a change of
occupation of which the insect is incapable for the moment. It is the
honey's turn and not the mortar's. The rule upon this point is
invariable. A moment comes, presently, when the harvesting is
interrupted and the masoning resumed. The edifice must be raised a
storey higher. Will the Bee, once more a builder, mixing fresh cement,
now attend to the leakage at the bottom? No more than before. What
occupies her at present is the new floor, whose brickwork would be
repaired at once, if it sustained a damage; but the bottom storey is
too old a part of the business, it is ancient history; and the worker
will not put a further touch to it, even though it be in serious
danger.
For the rest, the present and the following storeys will all have the
same fate. Carefully watched by the insect as long as they are in
process of building, they are forgotten and allowed to go to ruin once
they are actually built. Here is a striking instance: in a cell which
has attained its full height, I make a window, almost as large as the
natural opening, and place it about half-way up, above the honey. The
Bee brings provisions for some time longer and then lays her egg.
Through my big window, I see the egg deposited on the victuals. The
insect next works at the cover, to which it gives the finishing
touches with a series of little taps, administered with infinite care,
while the breach remains yawning. On the lid, it scrupulously stops up
every pore that could admit so much as an atom; but it leaves the
great opening that places the house at the mercy of the first-comer.
It goes to that breach repeatedly, puts in its head, examines it,
explores it with its antennae, nibbles the edges of it. And that is
all. The mutilated cell shall stay as it is, with never a dab of
mortar. The threatened part dates too far back for the Bee to think of
troubling about it.
I have said enough, I think, to show the insect's mental incapacity in
the presence of the accidental. This incapacity is confirmed by
renewing the test, an essential condition of all good experiments;
therefore my notes are full of examples similar to the one which I
have just described. To relate them would be mere repetition; I pass
them over for the sake of brevity.
The renewal of a test is not sufficient: we must also vary our test.
Let us, then, examine the insect's intelligence from another point of
view, that of the introduction of foreign bodies into the cell. The
Mason-bee is a housekeeper of scrupulous cleanliness, as indeed are
all the Hymenoptera. Not a spot of dirt is suffered in her honey-pot;
not a grain of dust is permitted on the surface of her mixture. And
yet, while the jar is open, the precious Bee-bread is exposed to
accidents. The workers in the cells above may inadvertently drop a
little mortar into the lower cells; the owner herself, when working at
enlarging the jar, runs the risk of letting a speck of cement fall
into the provisions. A Gnat, attracted by the smell, may come and be
caught in the honey; brawls between neighbours who are getting into
each other's way may send some dust flying thither. All this refuse
has to disappear and that quickly, lest afterwards the larva should
find coarse fare under its delicate mandibles. Therefore the Mason-
bees must be able to cleanse the cell of any foreign body. And, in
point of fact, they are well able to do so.
I place on the surface of the honey five or six bits of straw a
millimetre in length. (.039 inch.--Translator's Note.) Great
astonishment on the part of the returning insect. Never before have so
many sweepings accumulated in its warehouse. The Bee picks out the
bits of straw, one by one, to the very last, and each time goes and
gets rid of them at a distance. The effort is out of all proportion to
the work: I see the Bee soar above the nearest plane-tree, to a height
of thirty feet, and fly away beyond it to rid herself of her burden, a
mere atom. She fears lest she should litter the place by dropping her
bit of straw on the ground, under the nest. A thing like that must be
carried very far away.
I place upon the honey-paste a Mason-bee's egg which I myself saw laid
in an adjacent cell. The Bee picks it out and throws it away at a
distance, as she did with the straws just now. There are two
inferences to be drawn from this, both extremely interesting. In the
first place, that precious egg, for whose future the Bee labours so
indefatigably, becomes a valueless, cumbersome, hateful thing when it
belongs to another. Her own egg is everything; the egg of her next
door neighbour is nothing. It is flung on the dust-heap like any bit
of rubbish. The individual, so zealous on behalf of her family,
displays an abominable indifference for the rest of her kind. Each one
for himself. In the second place, I ask myself, without as yet being
able to find an answer to my question, how certain parasites go to
work to give their larva the benefit of the provisions accumulated by
the Mason-bee. If they decide to lay their egg on the victuals in the
open cell, the Bee, when she sees it, will not fail to cast it out; if
they decide to lay after the owner, they cannot do so, for she blocks
up the door as soon as her laying is done. This curious problem must
be reserved for future investigation. (Cf. "The Life of the Fly":
chapters 2 to 4; also later chapters in the present volume.--
Translator's Note.)
Lastly, I stick into the paste a bit of straw nearly an inch long and
standing well out above the rim of the cell. The insect extracts it by
dint of great efforts, dragging it away from one side; or else, with
the help of its wings, it drags it from above. It darts away with the
honey-smeared straw and gets rid of it at a distance, after flying
over the plane-tree.
This is where things begin to get complicated. I have said that, when
the time comes for laying, the Mason-bee arrives with a pellet of
mortar wherewith immediately to make a door to the house. The insect,
with its front legs resting on the rim, inserts its abdomen in the
cell; it has the mortar ready in its mouth. Having laid the egg, it
comes out and turns round to block the door. I wave it away for a
second, at the same time planting my straw as before, a straw sticking
out nearly a centimetre. (.39 inch.--Translator's Note.) What will the
Bee do? Will she, who is scrupulous in ridding the home of the least
mote of dust, extract this beam, which would certainly prove the
larva's undoing by interfering with its growth? She could, for just
now we saw her drag out and throw away, at a distance, a similar beam.
She could and she doesn't. She closes the cell, cements the lid, seals
up the straw in the thickness of the mortar. More journeys are taken,
not a few, in search of the cement required to strengthen the cover.
Each time, the mason applies the material with the most minute care,
while giving the straw not a thought. In this way, I obtain, one after
the other, eight closed cells whose lids are surmounted by my mast, a
bit of protruding straw. What evidence of obtuse intelligence!
This result is deserving of attentive consideration. At the moment
when I am inserting my beam, the insect has its mandibles engaged:
they are holding the pellet of mortar intended for the blocking-
operation. As the extracting-tool is not free, the extraction does not
take place. I expected to see the Bee relinquish her mortar and then
proceed to remove the encumbrance. A dab of mortar more or less is not
a serious business. I had already noticed that it takes my Mason-bees
a journey of three or four minutes to collect one. The pollen-
expeditions last longer, a matter of ten or fifteen minutes. To drop
her pellet, grab the straw with her mandibles, now disengaged, remove
it and gather a fresh supply of cement would entail a loss of five
minutes at most. The Bee decides differently. She will not, she cannot
relinquish her pellet; and she uses it. No matter that the larva will
perish by this untimely trowelling: the moment has come to wall up the
door; the door is walled up. Once the mandibles are free, the
extraction could be attempted, at the risk of wrecking the lid. But
the Bee does nothing of the sort: she keeps on fetching mortar; and
the lid is religiously finished.
We might go on to say that, if the Bee were obliged to depart in quest
of fresh mortar after dropping the first to withdraw the straw, she
would leave the egg unguarded and that this would be an extreme
measure which the mother cannot bring herself to adopt. Then why does
she not place the pellet on the rim of the cell? The mandibles, now
free, would remove the beam; the pellet would be taken up again at
once; and everything would go to perfection. But no: the insect has
its mortar and, come what may, employs it on the work for which it was
intended.
If any one sees a rudiment of reason in this Hymenopteron
intelligence, he has eyes that are more penetrating than mine. I see
nothing in it all but an invincible persistence in the act once begun.
The cogs have gripped; and the rest of the wheels must follow. The
mandibles are fastened on the pellet of mortar; and the idea, the wish
to unfasten them will never occur to the insect until the pellet has
fulfilled its purpose. And here is a still greater absurdity: the
plugging once begun is very carefully finished with fresh relays of
mortar! Exquisite attention is paid to a closing-up which is
henceforth useless; no attention at all to the dangerous beam. O
little gleams of reason that are said to enlighten the animal, you are
very near the darkness, you are naught!
Another and still more eloquent fact will finally convince whoso may
yet be doubting. The ration of honey stored up in a cell is evidently
measured by the needs of the coming larva. There is neither too much
nor too little. How does the Bee know when the proper quantity is
reached? The cells are more or less constant in dimension, but they
are not filled completely, only to about two-thirds of their height. A
large space is therefore left empty; and the victualler has to judge
of the moment when the surface of the mess has attained the right
level. The honey being perfectly opaque, its depth is not apparent. I
have to use a sounding-rod when I want to gauge the contents of the
jar; and I find, on the average, that the honey reaches a depth of ten
millimetres. (.39 inch.--Translator's Note.) The Bee has not this
resource; she has sight, which may enable her to estimate the full
section from the empty section. This presupposes the possession of a
somewhat geometric eye, capable of measuring the third of a distance.
If the insect did it by Euclid, that would be very brilliant of it.
What a magnificent proof in favour of its little intellect: a
Chalicodoma with a geometrician's eye, able to divide a straight line
into three equal parts! This is worth looking into seriously.
I take five cells, which are only partly provisioned, and empty them
of their honey with a wad of cotton held in my forceps. From time to
time, as the Bee brings new provisions, I repeat the cleansing-
process, sometimes clearing out the cell entirely, sometimes leaving a
thin layer at the bottom. I do not observe any pronounced hesitation
on the part of my plundered victims, even though they surprise me at
the moment when I am draining the jar; they continue their work with
quiet industry. Sometimes, two or three threads of cotton remain
clinging to the walls of the cells: the Bees remove them carefully and
dart away to a distance, as usual, to get rid of them. At last, a
little sooner or a little later, the egg is laid and the lid fastened
on.
I break open the five closed cells. In one, the egg has been laid on
three millimetres of honey (.117 inch.--Translator's Note.); in two,
on one millimetre (.039 inch.--Translator's Note.); and, in the two
others, it is placed on the side of the receptacle drained of all its
contents, or, to be more accurate, having only the glaze, the varnish
left by the friction of the honey-covered cotton.
The inference is obvious: the Bee does not judge of the quantity of
honey by the elevation of the surface; she does not reason like a
geometrician, she does not reason at all. She accumulates so long as
she feels within her the secret impulse that prompts her to go on
collecting until the victualling is completed; she ceases to
accumulate when that impulse is satisfied, irrespective of the result,
which in this case happens to be worthless. No mental faculty,
assisted by sight, informs her when she has enough, or when she has
too little. An instinctive predisposition is her only guide, an
infallible guide under normal conditions, but hopelessly lost when
subjected to the wiles of the experimenter. Had the Bee the least
glimmer of reason would she lay her egg on the third, on the tenth
part of the necessary provender? Would she lay it in an empty cell?
Would she be guilty of such inconceivable maternal aberration as to
leave her nurseling without nourishment? I have told the story; let
the reader decide.
This instinctive predisposition, which does not leave the insect free
to act and, through that very fact, saves it from error, bursts forth
under yet another aspect. Let us grant the Bee as much judgment as you
please. Thus endowed, will she be capable of meting out the future's
larva's portion? By no means. The Bee does not know what that portion
is. There is nothing to tell the materfamilias; and yet, at her first
attempt, she fills the honey-pot to the requisite depth. True, in her
childhood she received a similar ration, but she consumed it in the
darkness of a cell; and besides, as a grub, she was blind. Sight was
not her informant: it did not tell her the quantity of the provisions.
Did memory, the memory of the stomach that once digested them? But
digestion took place a year ago; and since that distant epoch, the
nurseling, now an adult insect, has changed its shape, its dwelling,
its mode of life. It was a grub; it is a Bee. Does the actual insect
remember that childhood's meal? No more than we remember the sups of
milk drawn from our mother's breast. The Bee, therefore, knows nothing
of the quantity of provisions needed by her larva, whether from
memory, from example or from acquired experience. Then what guides her
when she makes her estimate with such precision? Judgment and sight
would leave the mother greatly perplexed, liable to provide too much
or not enough. To instruct her beyond the possibility of a mistake
demands a special tendency, an unconscious impulse, an instinct, an
inward voice that dictates the measure to be apportioned.
CHAPTER 8. PARASITES.
In August or September, let us go into some gorge with bare and sun-
scorched sides. When we find a slope well-baked by the summer heat, a
quiet corner with the temperature of an oven, we will call a halt:
there is a fine harvest to be gathered there. This tropical land is
the native soil of a host of Wasps and Bees, some of them busily
piling the household provisions in underground warehouses: here a
stack of Weevils, Locusts or Spiders, there a whole assortment of
Flies, Bees, Mantes or Caterpillars, while others are storing up honey
in membranous wallets or clay pots, or else in cottony bags or urns
made with the punched-out disks of leaves.
With the industrious folk who go quietly about their business, the
labourers, masons, foragers, warehousers, mingles the parasitic tribe,
the prowlers hurrying from one home to the next, lying in wait at the
doors, watching for a favourable opportunity to settle their family at
the expense of others.
A heart-rending struggle, in truth, is that which rules the insect
world and in a measure our own world too. No sooner has a worker, by
dint of exhausting labour, amassed a fortune for his children than the
non-producers come hastening up to contend for its possession. To one
who amasses there are sometimes five, six or more bent upon his ruin;
and often it ends not merely in robbery but in black murder. The
worker's family, the object of so much care, for whom that home was
built and those provisions stored, succumb, devoured by the intruders,
directly the little bodies have acquired the soft roundness of youth.
Shut up in a cell that is closed on every side, protected by its
silken covering, the grub, once its victuals are consumed, sinks into
a profound slumber, during which the organic changes needed for the
future transformation take place. For this new hatching, which is to
turn a grub into a Bee, for this general remodelling, the delicacy of
which demands absolute repose, all the precautions that make for
safety have been taken.
These precautions will be foiled. The enemy will succeed in
penetrating the impregnable fortress; each foe has his special
tactics, contrived with appalling skill. See, an egg is inserted by
means of a probe beside the torpid larva; or else, in the absence of
such an implement, an infinitesimal grub, an atom, comes creeping and
crawling, slips in and reaches the sleeper, who will never wake again,
already a succulent morsel for her ferocious visitor. The interloper
makes the victim's cell and cocoon his own cell and his own cocoon;
and next year, instead of the mistress of the house, there will come
from below ground the bandit who usurped the dwelling and consumed the
occupant.
Look at this one, striped black, white and red, with the figure of a
clumsy, hairy Ant. She explores the slope on foot, inspects every nook
and corner, sounds the soil with her antennae. She is a Mutilla, the
scourge of the cradled grubs. The female has no wings, but, being a
Wasp, she carries a sharp poniard. To novice eyes she would easily
pass for a sort of robust Ant, distinguished from the common ruck by
her garb of staring motley. The male, wide-winged and more gracefully
shaped, hovers incessantly a few inches above the sandy expanse. For
hours at a time, on the same spot, after the manner of the Scolia-wasp
he spies the coming of the females out of the ground. If our watch be
patient and persevering, we shall see the mother, after trotting about
for a bit, stop somewhere and begin to scratch and dig, finally laying
bare a subterranean gallery, of which there was nothing to betray the
entrance; but she can discern what is invisible to us. She penetrates
into the abode, remains there for a while and at last reappears to
replace the rubbish and close the door as it was at the start. The
abominable deed is done: the Mutilla's egg has been laid in another's
cocoon, beside the slumbering larva on which the newborn grub will
feed.
Here are others, all aglitter with metallic gleams: gold, emerald,
blue and purple. They are the humming-birds of the insect-world, the
Chrysis-wasps, or Golden Wasps, another set of exterminators of the
larvae overcome with lethargy in their cocoons. In them, the atrocious
assassin of cradled children lies hidden under the splendour of the
garb. One of them, half emerald and half pale-pink, Parnopes carnea by
name, boldly enters the burrow of Bembex rostrata at the very moment
when the mother is at home, bringing a fresh piece to her larva, whom
she feeds from day to day. To the elegant criminal, unskilled in
navvy's work, this is the one moment to find the door open. If the
mother were away, the house would be shut up; and the Golden Wasp,
that sneak-thief in royal robes, could not get in. She enters,
therefore, dwarf as she is, the house of the giantess whose ruin she
is meditating; she makes her way right to the back, all heedless of
the Bembex, her sting and her powerful jaws. What cares she that the
home is not deserted? Either unmindful of the danger or paralysed with
terror, the Bembex mother lets her have her way.
The unconcern of the invaded is equalled only by the boldness of the
invader. Have I not seen the Anthophora-bee, at the door to her
dwelling, stand a little to one side and make room for the Melecta to
enter the honey-stocked cells and substitute her family for the
unhappy parent's? One would think that they were two friends meeting
on the threshold, one going in, the other out!
It is written in the book of fate: everything shall happen without
impediment in the burrow of the Bembex; and next year, if we open the
cells of that mighty huntress of Gad-flies, we shall find some which
contain a russet-silk cocoon, the shape of a thimble with its orifice
closed with a flat lid. In this silky tabernacle, which is protected
by the hard outer shell, is a Parnopes carnea. As for the grub of the
Bembex, that grub which wove the silk and next encrusted the outer
casing with sand, it has disappeared entirely, all but the tattered
remnants of its skin. Disappeared how? The Golden Wasp's grub has
eaten it.
Another of these splendid malefactors is decked in lapis-lazuli on the
thorax and in Florentine bronze and gold on the abdomen, with a
terminal scarf of azure. The nomenclators have christened her Stilbum
calens, FAB. When Eumenes Amedei (A species of Mason-wasp.--
Translator's Note.) has built on the rock her agglomeration of dome-
shaped cells, with a casing of little pebbles set in the plaster, when
the store of Caterpillars is consumed and the secluded ones have hung
their apartments with silk, we see the Stilbum take her stand on the
inviolable citadel. No doubt some imperceptible cranny, some defect in
the cement, allows her to insert her ovipositor, which shoots out like
a probe. At any rate, about the end of the following May, the Eumenes'
chamber contains a cocoon which again is shaped like a thimble. From
this cocoon comes a Stilbum calens. There is nothing left of the
Eumenes' grub: the Golden Wasp has gorged herself upon it.
Flies play no small part in this brigandage. Nor are they the least to
be dreaded, weaklings though they be, sometimes so feeble that the
collector dare not take them in his fingers for fear of crushing them.
There are some clad in velvet so extraordinarily delicate that the
least touch rubs it off. They are fluffs of down almost as frail, in
their soft elegance, as the crystalline edifice of a snowflake before
it touches ground. They are called Bombylii.
With this fragility of structure is combined an incomparable power of
flight. See this one, hovering motionless two feet above the ground.
Her wings vibrate so rapidly that they appear to be in repose. The
insect looks as though it were hung at one point in space by some
invisible thread. You make a movement; and the Bombylius has
disappeared. You cast your eyes in search of her around you, far away,
judging the distance by the vigour of her flight. There is nothing
here, nothing there. Then where is she? Close by you. Look at the
point whence she started: the Bombylius is there again, hovering
motionless. From this aerial observatory, as quickly recovered as
quitted, she inspects the ground, watching for the favourable moment
to establish her egg at the cost of another creature's destruction.
What does she covet for her offspring: the honey-cupboard, the stores
of game, the larvae in their transformation-sleep? I do not know yet,
What I do know is that her slender legs and her dainty velvet dress do
not allow her to make underground searches. When she has found the
propitious place, suddenly she will swoop down, lay her egg on the
surface in that lightning touch with the tip of her abdomen and
straightway fly up again. What I suspect, for reasons set forth
presently, is that the grub that comes out of the Bombylius' egg must,
of its own motion, at its own risk and peril, reach the victuals which
the mother knows to be close at hand. She has no strength to do more;
and it is for the new-born grub to make its way into the refectory.
I am better acquainted with the manoeuvres of certain Tachinae, the
tiniest of pale-grey Flies, who, cowering on the sand in the sun, in
the neighbourhood of a burrow, patiently await the hour at which to
strike the fell blow. Let a Bembex-wasp return from the chase, with
her Gad-fly; a Philanthus, with her Bee; a Cerceris, with her Weevil;
a Tachytes, with her Locust: straightway the parasites are there,
coming and going, turning and twisting with the Wasp, always at her
rear, without allowing themselves to be put off by any cautious
feints. At the moment when the huntress goes indoors, with her
captured game between her legs, they fling themselves on her prey,
which is on the point of disappearing underground, and nimbly lay
their eggs upon it. The thing is done in the twinkling of an eye:
before the threshold is crossed, the carcase holds the germs of a new
set of guests, who will feed on victuals not amassed for them and
starve the children of the house to death.
This other, resting on the burning sand, is also a member of the Fly
tribe; she is an Anthrax. (Cf. "The Life of the Fly": chapter 2.--
Translator's Note.) She has wide wings, spread horizontally, half
smoked and half transparent. She wears a dress of velvet, like the
Bombylius, her near neighbour in the official registers; but, though
the soft down is similar in fineness, it is very different in colour.
Anthrax is Greek for coal. It is a happy denomination, reminding us of
the Fly's mourning livery, a coal-black livery with silver tears. The
same deep mourning garbs those parasitic Bees, and these are the only
instances known to me of that violent opposition of dead black and
white.
Nowadays, when men interpret everything with glorious assurance, when
they explain the Lion's tawny mane as due to the colour of the African
desert, attribute the Tiger's dark stripes to the streaks of shadow
cast by the bamboos and extricate any number of other magnificent
things with the same facility from the mists of the unknown, I should
not be sorry to hear what they have to say of the Melecta, the Crocisa
and the Anthrax and of the origin of their exceptional costume.
The word 'mimesis' has been invented for the express purpose of
designating the animal's supposed faculty of adapting itself to its
environment by imitating the objects around it, at least in the matter
of colouring. We are told that it uses this faculty to baffle its
foes, or else to approach its prey without alarming it. Finding itself
the better for this dissimulation, a source of prosperity indeed, each
race, sifted by the struggle for life, is considered to have preserved
those best-endowed with mimetic powers and to have allowed the others
to become extinct, thus gradually converting into a fixed
characteristic what at first was but a casual acquisition. The Lark
became earth-coloured in order to hide himself from the eyes of the
birds of prey when pecking in the fields; the Common Lizard adopted a
grass-green tint in order to blend with the foliage of the thickets in
which he lurks; the Cabbage-caterpillar guarded against the bird's
beak by taking the colour of the plant on which it feeds. And so with
the rest.
In my callow youth, these comparisons would have interested me: I was
just ripe for that kind of science. In the evenings, on the straw of
the threshing-floor, we used to talk of the Dragon, the monster which,
to inveigle people and snap them up with greater certainty, became
indistinguishable from a rock, the trunk of a tree, a bundle of twigs.
Since those happy days of artless credulity, scepticism has chilled my
imagination to some extent. By way of a parallel with the three
examples which I have quoted, I ask myself why the White Wagtail, who
seeks his food in the furrows as does the Lark, has a white shirt-
front surmounted by a magnificent black stock. This dress is one of
those most easily picked out at a distance against the rusty colour of
the soil. Whence this neglect to practise mimesis, 'protective
mimicry'? He has every need of it, poor fellow, quite as much as his
companion in the fields!
Why is the Eyed Lizard of Provence as green as the Common Lizard,
considering that he shuns verdure and chooses as his haunt, in the
bright sunlight, some chink in the naked rocks where not so much as a
tuft of moss grows? If, to capture his tiny prey, his brother in the
copses and the hedges thought it necessary to dissemble and
consequently to dye his pearl-embroidered coat, how comes it that the
denizen of the sun-blistered rocks persists in his blue-and-green
colouring, which at once betrays him against the whity-grey stone?
Indifferent to mimicry, is he the less skilful Beetle-hunter on that
account, is his race degenerating? I have studied him sufficiently to
be able to declare with positive certainty that he continues to thrive
both in numbers and in vigour.
Why has the Spurge-caterpillar adopted for its dress the gaudiest
colours and those which contrast most with the green of the leaves
which it frequents? Why does it flaunt its red, black and white in
patches clashing violently with one another? Would it not be worth its
while to follow the example of the Cabbage-caterpillar and imitate the
verdure of the plant that feeds it? Has it no enemies? Of course it
has: which of us, animals and men, has not?
A string of these whys could be extended indefinitely. It would give
me amusement, did my time permit me, to counter each example of
protective mimicry with a host of examples to the contrary. What
manner of law is this which has at least ninety-nine exceptions in a
hundred cases? Poor human nature! There is a deceptive agreement
between a few actual facts and the theory which we are so foolishly
ready to believe; and straightway we interpret the facts in the light
of the theory. In a speck of the immense unknown we catch a glimpse of
a phantom truth, a shadow, a will-o'-the-wisp; once the atom is
explained, for better or worse, we imagine that we hold the
explanation of the universe and all that it contains; and we forthwith
shout:
'The great law of Nature! Behold the infallible law!'
Meanwhile, the discordant facts, an innumerable host, clamour at the
gates of the law, being unable to gain admittance.
At the door of that infinitely restricted law clamour the great tribe
of Golden Wasps, whose dazzling splendour, worthy of the wealth of
Golconda, clashes with the dingy colour of their haunts. To deceive
the eyes of their bird-tyrants, the Swift, the Swallow, the Chat and
the others, these Chrysis-wasps, who glow like a carbuncle, like a
nugget in the midst of its dark veinstone, certainly do not adapt
themselves to the sand and the clay of their downs. The Green
Grasshopper, we are told, thought out a plan for gulling his enemies
by identifying himself in colour with the grass in which he dwells,
whereas the Wasp, so rich in instinct and strategy, allowed herself to
be distanced in the race by the dull-witted Locust! Rather than adapt
herself as the other does, she persists in her incredible splendour,
which betrays her from afar to every insect-eater and in particular to
the little Grey Lizard, who lies hungrily in wait for her on the old
sun-tapestried walls. She remains ruby, emerald and turquoise amidst
her grey environment; and her race thrives none the worse.
The enemy that eats you is not the only one to be deceived; mimesis
must also play its colour-tricks on him whom you have to eat. See the
Tiger in his jungle, see the Praying Mantis on her green branch. (For
the Praying Mantis, cf. "Social Life in the Insect World", by J.H.
Fabre, translated by Bernard Miall: chapters 5 to 7.--Translator's
Note.) Astute mimicry is even more necessary when the one to be duped
is an amphitryon at whose cost the parasite's family is to be
established. The Tachinae seem to declare as much: they are grey or
greyish, of a colour as undecided as the dusty soil on which they
cower while waiting for the arrival of the huntress laden with her
capture. But they dissemble in vain: the Bembex, the Philanthus and
the others see them from above, before touching ground; they recognize
them perfectly at a distance, despite their grey costume. And so they
hover prudently above the burrow and strive, by sudden feints, to
mislead the traitorous little Fly, who, on her side, knows her
business too well to allow herself to be enticed away or to leave the
spot where the other is bound to return. No, a thousand times no:
clay-coloured though they be, the Tachinae have no better chance of
attaining their ends than a host of other parasites whose clothing is
not of grey frieze to match the locality frequented, as witness the
glittering Chrysis, or the Melecta and the Crocisa, with their white
spots on a black ground.
We are also told that, the better to cozen his amphitryon, the
parasite adopts more or less the same shape and colouring; he turns
himself, in appearance, into a harmless neighbour, a worker belonging
to the same guild. Instance the Psithyrus, who lives at the expense of
the Bumble-bee. But in what, if you please, does Parnopes carnea
resemble the Bembex into whose home she penetrates in her presence? In
what does the Melecta resemble the Anthophora, who stands aside on her
threshold to let her pass? The difference of costume is most striking.
The Melecta's deep mourning has naught in common with the Anthophora's
russet coat. The Parnopes' emerald-and-carmine thorax possesses not
the least feature of resemblance with the black-and-yellow livery of
the Bembex. And this Chrysis also is a dwarf in comparison with the
ardent Nimrod who goes hunting Gad-flies.
Besides, what a curious idea, to make the parasite's success depend
upon a more or less faithful likeness with the insect to be robbed!
Why, the imitation would have exactly the opposite effect! With the
exception of the Social Bees, who work at a common task, failure would
be certain, for here, as among mankind, two of a trade never agree. An
Osmia, an Anthophora, a Chalicodoma had better be careful not to poke
an indiscreet head in at her neighbour's door: a sound drubbing would
soon recall her to a sense of the proprieties. She might easily find
herself with a dislocated shoulder or a mangled leg in return for a
simple visit which was perhaps prompted by no evil intention. Each for
herself in her own stronghold. But let a parasite appear, meditating
foul play: that's a very different thing. She can wear the trappings
of Harlequin or of a church-beadle; she can be the Clerus-beetle, in
wing-cases of vermilion with blue trimmings, or the Dioxys-bee, with a
red scarf across her black abdomen, and the mistress of the house will
let her have her way, or, if she become too pressing, will drive her
off with a mere flick of her wing. With her, there is no serious fray,
no fierce fight. The Bludgeon is reserved for the friend of the
family. Now go and practice your mimesis in order to receive a welcome
from the Anthophora or the Chalicodoma! A few hours spent with the
insects themselves will turn any one into a hardened scoffer at these
artless theories.
To sum up, mimesis, in my eyes, is a piece of childishness. Were I not
anxious to remain polite, I should say that it is sheer stupidity; and
the word would express my meaning better. The variety of combinations
in the domain of possible things is infinite. It is undeniable that,
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