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.





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