regards their charge, a zeal and an attachment which would justly merit
our attention, even were they the real parents of these insects; how
much greater then must be our astonishment, when we consider that they
bear no further relation to them, than that of being born under the
same roof. Several males and females lay in their enveloping membrane
in one of the largest cavities of my glazed ant-hill. The Labourers,
assembled together, appeared to be in continual motion around them. I
noticed three or four mounted upon one of these cocoons, endeavouring
to open it with their teeth at that extremity answering to the head
of the pupa; they began thinning it, by tearing away some threads
of silk where they wished to pierce it; and at length, by dint of
pinching and biting this tissue, so extremely difficult to break, they
formed in it a vast number of apertures. They afterwards attempted to
enlarge these openings, by tearing or drawing away the silk; but these
efforts proving ineffectual, they passed one of their teeth into the
cocoon, through the apertures they had formed, and by cutting each
thread, one after the other, with great patience, at length effected
a passage, of a line in diameter, in the superior part of the web.
They now uncovered the head and feet of the insect to which they were
desirous of giving liberty, but before they could release it, it was
absolutely necessary to enlarge the opening; for this purpose, these
guardians cut out a portion in the longitudinal direction of the
cocoon, with their teeth alone, employing these instruments as we are
in the habit of employing a pair of scissars. A considerable degree of
agitation prevailed in this part of the ant-hill; a number of ants were
occupied in disengaging the winged individual of its envelope; they
took repose and relieved each other by turns, evincing great eagerness
in seconding their companions in this undertaking.[8] To effect its
speedy liberation, some raised up the portion or _bandalette_ cut out
in the length of the cocoon; whilst others drew it gently from its
imprisonment. When the ant was extricated from its enveloping membrane,
it was not, like other insects, capable of enjoying its freedom,
and taking flight: nature did not will it that it should so soon be
independent of the labourers. It could neither fly, nor walk, nor
without difficulty stand; for the body was still confined by another
membrane, from which it could not, by its own exertions, disengage
itself.
[8] Among those ants I kept in confinement, I observed that
considerable bustle prevailed when any of the pupæ were about to quit
the cocoon. For the most part, two or three stationed themselves on
or near each cocoon. From seeing, more than once, two engaged in the
operation of extricating the imprisoned ant from its envelope, I was
desirous of ascertaining whether a single worker could accomplish this
operation. I therefore placed in a wine glass with a little moistened
earth one of the Yellow Ants with three or four pupæ; the first object
with this little creature, was that of excavating a chamber for the
deposition of its treasure. The pupæ were then brought up, and laid on
the surface of the earth, from day to day, to receive the sun’s warmth.
In a few days, I saw the scattered remnants of one of the cocoons,
and the worker with his assistant engaged in giving liberty to the
remaining ants. I did not, at the time, notice whether the pupæ were
or were not capable of effecting their own liberation; but according
to the statement of De Geer, the pupa dies when neglected by the
workers.--T.
In this fresh embarrassment, the labourers did not forsake it; they
removed the satin-like pellicle which embraced every part of the body,
drew the antennæ gently from their investment, then disengaged the feet
and the wings, and lastly, the body, the abdomen, and its peduncle.
The insect was now in a condition to walk and receive nourishment, for
which it appeared there was urgent need. The first attention therefore,
paid it by the guardians, was that of giving it the food I had placed
within their reach.
The ants in every part of the ant-hill were occupied in giving liberty
to the males, females, and young labourers, that were still enveloped.
On being dispossessed of their coverings, the remnants were collected
and placed aside in one of the most distant lodges of their habitation;
for these insects observe the greatest order and regularity. Some
species of ants remove these shreds to a distance from the ant-hill,
others, cover the exterior surface of their nest with them, or collect
them in particular apartments.[9]
[9] M. Latreille has remarked, as well as De Geer, that, among the
Ash-coloured Ants, there are some pupæ which are naked, others enclosed
in a cocoon; but he does not know if there are any that undergo their
metamorphosis without spinning, or if the workers tear off their
enveloping membrane; however he leans to this latter opinion. I have
often made the same remark. I have even confirmed the conjecture he
had advanced, and often seen the ash-coloured labourers opening the
cocoon of the pupæ, a short period after their transformation. The
Mining Ants act the same: but for what purpose do they hasten to
liberate them, and of what advantage is it to the larvæ to spin, if
the workers so soon destroy the tissue they have woven? It cannot be
for the sake of unfolding their members from the last envelope in the
state of pupæ, for the ants do not render them this service until
they are capable of motion, and have acquired their full strength:
they even know the precise moment when to remove them. Are not these
cocoons of essential service to the larvæ at the time of passing to
the state of pupæ? I have frequently drawn from their cocoons, larvæ
which had just spun, and which were not yet metamorphosed: some days
after, they began rejecting their larva-skin, but could not disengage
their limbs, which, with the abdomen, remained attached to it. The
ants offered them no assistance. These pupæ were never well developed,
and they soon perished. It appears that these cocoons offered them
a point of support, enabling them to free themselves from the skin
which they are under the necessity of rejecting. It will be objected,
perhaps, that the larvæ of several species never spin, and they would
of course experience the same inconvenience as those I drew too hastily
from their cocoon. To this I answer, that nature has provided for this
case in another manner:--the body of these Ants is very different
from that of others, their elongated peduncle gives greater liberty
to the abdomen, to move, bend, and extend itself, than the peduncle
of the first, which is closely attached to the corslet. They have, in
addition, a sting, which may also facilitate their developement, for
the pupæ at first possess much strength and vivacity, although they
soon after pass into a state of lethargy.--A.
The labourers we have seen in charge of the larvæ and pupæ evince the
same solicitude for the ants, freshly transformed: they lie for some
days under the necessity of watching and following them; they accompany
them in their excursions, point out to them the paths and labyrinths of
their habitation, and nourish them with the greatest care; they also
perform the difficult task of extending the wings of the males and
females, which would otherwise remain folded up, and acquit themselves
with such address, as not to injure these frail and delicate members.
At one time, they bring together, in the same apartments, the males
they find rambling; at another time, act as guides in conducting them
from the ant-hill. In short, the labourers appear to have the complete
direction of their conduct, as long as they remain there, and neglect
not to discharge the several duties, connected with these insects
(whose strength is not yet developed) until the period of their taking
flight for the purpose of continuing their kind.
How can we sufficiently admire the assiduity which the labouring ants
evince for the little ones whose safety is confided to them!--By what
bond has nature attached them so strongly to the progeny of another
mother! This question having a reference to the different families
composed of three sorts of individuals,--the labourers, charged with
educating the young, fabricating, and provisioning the nest; and those
upon whom the office devolves of multiplying the species,--deserves
to be treated at greater length, and with greater attention, than our
confined knowledge permits. But we have a glimpse, however, of the
secret of this singular constitution, in the resemblance the labourers
have with the female ants, relatively to their external sexual organs.
The connexion which exists between ants, and hive and humble bees,
throws additional light upon this subject, by showing us labourers
demi-fecund with the one[10], and little rival females, abundant
enough with the other.[11] That solicitude also which the labouring
ants evince for the larvæ, whose birth they have witnessed, clearly
discovers their sex, and would be sufficient to prove that they are
neither neuters nor males, even if the conduct of the males towards
them did not indicate that they belong to the class of females. This
observation, which I have several times made, (the details of which I
suppress,) leaves me in no doubt upon this point. I shall here only
add, that I have never known the labouring ants produce eggs, and have
constantly found the approach of the male attended with the sacrifice
of their lives.
[10] Nouvelles Observations sur les Abeilles, par F. Huber.
[11] V. Linn. Trans. vol. vi. Memoir upon Humble Bees, by the Author of
these researches.
But with what view does nature permit as many sterile females among
ants as among wasps and bees? Is it not in order to increase the number
of individuals, in the same family, without producing a population that
would be more than proportioned to it?--In reserving a certain number
of females for conception, she has appointed others to take care of the
infant generation. She has even deprived the latter of the faculty of
flying; but in return for this, they enjoy a sweet recompense, either
(as we have no reason to doubt) by their being inspired for their
charge with the sentiments of mothers for their young, or by their
having an unlimited power over the other orders of the society in which
they live; a truth which I hope to establish in the course of this
work, and which differs widely from the received opinion, that these
republics are governed by several chiefs.
CHAP. III.
OF THE FECUNDATION, &C. OF ANTS.
1. _Departure of the Winged Ants._
Were we unable to determine the sexes of ants from the appearance
of those light and membranous wings with which some are furnished,
and others totally unprovided, we should still conclude, that the
former were destined to change their place of abode, the latter to
remain on the spot where they receive their birth. That prerogative
which distinguishes the males and females from the workers, has not
been granted them for the advantage of the colony in which they pass
the first period of their existence. They are neither called upon
to provision their abode, nor to seek, afar off, materials for its
construction. Nature has endowed them with instruments of flight, for
the well-being and continuance of the species, and for the purpose
of establishing ant-hills in every situation, and forming numerous
colonies. But how are these new colonies established? What particulars
do the amours of these winged ants offer us? Do the males and females
live in common? Have they the same instinct as the workers? What a
variety of questions could we not propose on this subject; a subject
hitherto but slightly touched upon, and by comparatively few authors,
and whose importance, as it regards the economy of ants, merits the
closest attention.
Having observed these insects in the interior of the ant-hill, remarked
their education, and the cares bestowed upon them, to the period when
they are in a condition to walk or fly, we shall now follow them out
of the nest, and, as far as possible, in their aërial excursions.
Let us lose sight for one moment of the glazed ant-hill. Let us retire
to a meadow, on a fine summer’s day, at a time when they first make
use of their wings, and take a survey of their habitation, on the
surface of which we shall observe walking to and fro many of its
winged inhabitants. These are the males and females of the Field Ants;
they climb all the plants which surround their residence, and are
every where accompanied by a multitude of workers, who follow their
steps with ceaseless solicitude. Some, however, attempt to retain and
reconduct them to the ant-hill; but the greater part content themselves
with simply escorting them. They offer them nourishment for the last
time, and render them the last token of their care and affection.
The dome of the ant-hill does not afford the winged ants a sufficiently
ample field for the display of their amours; the crowd by which they
are constantly surrounded seems to embarrass their movements; they soon
come to the determination of taking flight, and seeking in the air a
wider theatre, in which they can accomplish the wish of nature. But
what are those dazzling objects we see on that little hillock rising
above the grass? They are the male Ants who come forth by hundreds from
their subterranean residence, and display their silvery and transparent
wings as they wander over the surface of their nest. The females,
who are in much smaller number, soon join their paramours, proudly
displaying their big and highly bronzed abdomen, and occasionally
extending their glittering wings, whose ever-varying lustre adds much
to the beauty of this interesting assemblage.
Disorder and agitation are now manifest in the ant-hill; the bustle
increases every moment, the winged insects climb with great briskness
the neighbouring plants, followed by a numerous retinue of workers,
who are continually running from one male to another, touching them
with their antennæ, and offering them food.
The males, at length, quit the paternal roof and take flight, as from
one general impulse, in which they are quickly followed by the females.
The winged tribe soon disappear. The workers retrace for some instants
the steps of these highly favoured beings, to whom they have shown such
extreme care and attention, and whom they are never destined to see
more.
Many pleasing pictures are exhibited by the variety in colour and
form of this assemblage of insects. In some, the whole body is of one
uniform colour; the workers being yellow, the males black, and the
females flaxen. Their wings display all the brilliant hues of the
rainbow. In others, the body of the workers is of a dark ash-colour,
stained with red upon the corslet; the males, whose body is a deep
black, have the feet of a fine yellow, and the wings whitish;
the females have the corslet and abdomen brown, ornamented with
orange-coloured spots; the wings are transparent and blackish at their
extremities.
It is requisite that the temperature of the air should be at the 15°
or 16° of Reaumur (67° Fahrenheit), to allow of our witnessing the
departure of the males and females: unless this be the case, they
continue within the nest, sheltered from the wet and the cold air. When
the weather is favourable, the labourers, who seem to be aware of it,
form several apertures in the ant-hill, to give a ready passage to the
crowd that are about to quit it. The males and females may be then seen
coming to take the air at the entrance. The hour of departure arrives:
they all take flight. The workers alone re-enter the nest, and close
the entrances.
But let us continue our course, and still follow the winged ants in
their flight. A shower of these insects soon arrests the attention.
They fall from some height in the air, by pairs, roll themselves in
the dust, and sport in the grass. With some, the junction takes place
previous to their reaching the ground; with others, it is effected
upon the plants where they rest; some few disengage themselves from
their companions, and, mounting in the air, rejoin a cloud of other
winged ants, collected near the top of a tree, around which they
make continual evolutions. A little further off, I perceive other
assemblages of these winged insects, but of a different species; they
appear at a less height than the former, and somewhat resemble the
swarming of bees. The term of swarm, however, does not strictly apply
to this concourse of insects, who have no further object than that
of meeting each other, and effecting their union in the air, and who
do not assemble for the purpose of founding a new colony. I shall,
notwithstanding, use this expression, when speaking of a numerous
assemblage of ants, who fly about with a buzzing sound, without
separating. I presently perceived I was surrounded by winged ants:
several females were in the midst of this swarm; and these are they
who, doubtless, draw together all the males of which it is composed.
The swarm takes no particular direction, neither removing from, nor
approaching the ant-hill they had left; but, in place of this, raise
and lower themselves alternately, about ten feet from the surface of
the ground. Whilst this general movement takes place, which is effected
with considerable slowness, all the males forming the main body of the
swarm, fly in a zig-zag direction, with considerable rapidity: the
females, on the contrary, remain suspended, like balloons; they face
the wind, and seem in a state of immobility. They continue, however,
to ascend and descend with the swarm, until the males dart upon them,
separate them from the crowd, and impregnate them, even in mid-air.
I have often noticed, in the month of September, similar swarms. These
insects admitted of easy observation, since they were unembarrassed
by my presence. The sound produced by myriads of these insects did
not equal that of a single wasp. In every part of the meadow, these
assemblages might be witnessed: a zephyr was sufficient to disperse
them, but they quickly reformed a compact body. It often happened
several swarms were so intermingled as to constitute but one. I have
seen very considerable swarms, but ascertained nothing particular
respecting them.[1]
[1] Assemblages of winged ants have been also witnessed in this
country, as is evidenced by the following quotation:--“In the beginning
of August, 1812, I was going up the Orford river, in Suffolk, in a
row-boat, in the evening, when my attention was caught by an infinite
number of winged ants, both males and females, at which the fish were
every where darting, floating alive upon the surface of the water.
While passing the river, these had probably been precipitated into
it, either by the wind, or by a heavy shower, which had just fallen.
Captain Haverfield, R. N., gave me an account of an extraordinary
appearance of ants observed by him in the Medway, in the autumn of
1814, when he was first-lieutenant of the Clorinde, which is confirmed
by the following letter, addressed by the surgeon of that ship, now
Dr. Bromley, to Mr. Mac Leay:--‘In Sept. 1814, being on the deck of
the hulk of the Clorinde, my attention was drawn to the water by the
first-lieutenant (Haverfield) observing there was something black
floating down with the tide. On looking with a glass, I discovered they
were insects. The boat was sent, and brought a bucket full of them on
board; they proved to be a large species of ant, and extended from the
upper part of Salt-pan reach, out towards the great Nore, a distance
of five or six miles. The column appeared to be in breadth eight or
ten feet, and in height about six inches, which, I suppose, must have
been from their resting one upon another.’ These ants were winged.
Whence this immense column came was not ascertained. From the number
here agglomerated, one would think that all the ant-hills of Kent and
Surrey could scarcely have furnished a sufficient number of males and
females to form it. When Colonel Sir Augustus Frazer, of the Horse
Artillery, was surveying, on the 6th of October, 1813, the scene of the
battle of the Pyrennees from the summit of the mountain called Pena de
Aya, or Les quatre Couronnes, he and his friends were enveloped by a
swarm of ants, so numerous as entirely to intercept their view, so that
they were glad to remove to another station, in order to get rid of
them.”--_Introduction to Entomology_, by Kirby and Spence, Vol. II. p.
53.--T.
When a large body of these insects were hovering immediately over my
head, it would seem that I alone possessed the power of inducing them
to change their station, and of uniting them to others I observed
in the meadows. To effect this, I had only to walk slowly, the swarm
by which I was surrounded following and accompanying me in all my
movements, which I attribute either to my drawing after me the column
of air in which they were flying, or to their regarding me as the base
above which they were elevated, and, therefore, not aware of their
removing from the point of departure. I have never witnessed any of
those extensive swarms, of which M. Gleditsch has given us an account,
in the Memoirs of the Academy of Berlin. “He observed,” he says, “an
immense swarm of ants, which, viewed at a distance, produced an effect
very much resembling an aurora borealis, when, from the border of the
cloud, appear by jets several columns of flame and vapour, attended
with a variety of luminous rays and lines, forming no unapt resemblance
to forked lightning, although destitute of its brilliancy. Columns
of ants, but less distinct, were seen moving here and there, with
inexpressible swiftness, continually elevating, so that they at length
appeared to soar above the clouds. Arrived at this point, they so far
from totally, or even in part disappearing, seemed to form a more
compact body, becoming darker, from time to time. Other moving columns,
but more dilatory in their progress, followed the first, rising, in
like manner, occasionally darting forth, or mounting after each other
with equal swiftness. These several columns continued in motion during
the space of half an hour. Each column presented a species of close
net-work, and had an intestinal or undulating movement. On regarding
them a little nearer, I found them to consist of a numerous body of
flying insects. These insects, of small size, entirely black, and
winged, preserved the form of an unbroken column, continually ascending
and descending with great regularity.”[2]
[2] Bomare, Dict. d’Hist. Nat.
One would be inclined to believe, that these winged ants, whose aërial
excursions are completed, and whose impregnation has taken place
before us, recalled to the ant-hill, by an instinctive impulse, would
return to increase the population of their nest; that the males, now
useless, after consuming a part of the provisions of the large family
of which they are members, would experience the cruel fate attending
those of bees, and that the females would commit their eggs to the
charge of the same individuals who protected them in their infancy.
Several authors entertain this opinion, (among others De Geer); but
they advance nothing in support of it. It will be therefore expedient
to discuss the question which naturally arises from these facts.
The male and female ants, when they take a long flight from the
ant-hill, do not show that singular instinct which guides bees, wasps,
and other insects, in again finding their habitation. This instinct
consists, in their knowing how to move in every direction around their
abode, without straggling, in order to examine its position, and the
several places in its vicinity. We may be soon convinced of this by
displacing a hive. The first day the bees never venture abroad, unless
they have previously visited all the neighbouring objects: they turn
round on all sides, keeping an eye upon their dwelling, without which,
it may be readily conceived, it would be impossible they could return.
The Queen Bee does the same when she goes forth to meet her paramour in
the air.[3] But our winged ants, on the contrary, when they quit the
ant-hill, keep their back continually towards it, and go off in a right
line to a distance, from which it would be no easy matter to perceive
it. We might from this infer, that they would never return to it. But I
did not confine myself entirely to this observation; for I kept sentry,
from the time of their departure until night, and even several days in
succession, to be fully assured they did not return to the ant-hill.
In this way I have arrived at the conviction, that their return is
one of those fables with which we have been a long time amused. What,
then, becomes of these insects, accustomed as they have been, to live
in a convenient spacious abode, sheltered from every inclemency of the
weather, and receiving every attention from the labourers, suddenly
relying upon their own guidance, deprived of all these advantages? This
we shall learn in the following section.
[3] _Vide_ Observations upon Bees, addressed to Ch. Bonnet.
2. _History of Winged Ants after Impregnation._