aperture which gave entrance to the ant-hill. It placed in a heap
the several fragments it had scraped up, and formed them into small
pellets, which it deposited here and there upon the nest. It returned
constantly to the same place, and appeared to have a marked design, for
it laboured with ardour and perseverance. I remarked a slight furrow,
excavated in the ground in a straight line, representing the plan of
a path or gallery. The Labourer, the whole of whose movements fell
under my immediate observation, gave it greater depth and breadth, and
cleared out its borders; and I saw, at length--in which I could not be
deceived--that it had the intention of establishing an avenue which
was to lead from one of the stories to the under-ground chambers. This
path, which was about two or three inches in length, and formed by a
single ant, was opened above, and bordered on each side by a buttress
of earth: its concavity _en forme de gouttiere_ was of the most perfect
regularity; for the architect had not left an atom too much. The work
of this ant was so well followed and understood, that I could almost
to a certainty guess its next proceeding, and the very fragment it was
about to remove. At the side of the opening where this path terminated,
was a second opening to which it was necessary to arrive by some
road. The same ant engaged in and executed alone this undertaking. It
furrowed out and opened another path, parallel to the first, leaving
between each a little wall of three or four lines in height.
Those ants who lay the foundation of a wall, a chamber, or gallery,
from working separately, occasion now and then a want of coincidence
in the parts of the same or different objects. Such examples are of
no unfrequent occurrence, but they by no means embarrass them. What
follows proves that the workman, on discovering his error, knew how to
rectify it.
A wall had been erected with the view of sustaining a vaulted ceiling,
still incomplete, that had been projected from the wall of the opposite
chamber. The workman who began constructing it, had given it too little
elevation to meet the opposite partition upon which it was to rest. Had
it been continued on the original plan, it must infallibly have met
the wall at about one-half of its height, and this it was necessary
to avoid. This state of things very forcibly claimed my attention;
when one of the ants, arriving at the place, and visiting the works,
appeared to be struck by the difficulty which presented itself; but
this it as soon obviated, by taking down the ceiling and raising the
wall upon which it reposed. It then, in my presence, constructed a new
ceiling with the fragments of the former one.
When the ants commence any undertaking, one would suppose that they
worked after some preconceived idea, which indeed would seem verified
by the execution. Thus, should any ant discover upon the nest, two
stalks of plants, which lie cross-ways, a disposition favourable to
the construction of a lodge; or some little beams that may be useful
in forming its angles and sides, it examines the several parts with
attention, then distributes with much sagacity and address parcels of
earth, in the spaces, and along the stems, taking from every quarter
materials adapted to its object, sometimes, not caring to destroy the
work that others had commenced; so much are its motions regulated
by the idea it has conceived, and upon which it acts, with little
attention to all else around it. It goes and returns, until the plan is
sufficiently understood by its companions.
In another part of the same ant-hill, several fragments of straw seemed
expressly placed to form the roof of a large house; a workman took
advantage of this disposition: these fragments lying horizontally, at
half an inch distance from the ground, formed, in crossing each other,
an oblong parallelogram. The industrious insect commenced, by placing
earth in the several angles of this _carpentering_ work, and all along
the little beams of which it was composed. The same workman afterwards
placed several rows of the same materials against each other, when the
roof became very distinct. On perceiving the possibility of profiting
by another plant, to support a vertical wall, it began laying the
foundations of it; other ants having by this time arrived, finished in
common what this had commenced.[8]
[8] I have often been surprised at the ingenuity of these little
creatures, in availing themselves of contiguous blades of grass, stalks
of corn, &c., when they wish to enlarge the boundaries of their abode.
As these are usually met with in the erect position, they are admirably
calculated for pillars; they, therefore coat them over with a fine
paste of earth, giving them, by additional layers, the solidity they
judge necessary for the work on which they are engaged: they then leave
them to be consolidated by the wind, and afterwards spring a number
of arches, from pillar to pillar, and thus form an extensive saloon.
Should they be, at any time, in want of small apartments, they have
only to prepare a quantity of moistened earth, and by placing this
between the pillars, and carrying it up to the roof, leaving here and
there an aperture for entrance, their object is completely attained.--T.
From these observations, and a thousand similar, I am convinced that
each ant acts independently of its companions. The first who conceives
a plan of easy execution, immediately gives the sketch of it; others
have only to continue what this has begun, judging, from an inspection
of the first labours, in what they ought to engage. They can all lay
down plans, and continue to polish or retouch their work as occasion
requires. The water furnishes the cement they require, and the sun and
air harden the materials of which their edifice is composed. They have
no other chisel than their teeth, no other compass than their antennæ,
and no other trowel than their fore-feet, of which they make use in an
admirable manner, to affix and consolidate the moistened earth.
These, then, are the material and mechanical means which they employ in
their building. In following an instinct purely mechanical, they might
execute with precision, a geometrical and invariable plan, construct
walls of equal length and breadth, vaulted ceilings, whose curve would
only require a servile _obeissance_, and we should have been but
moderately surprised by their industry: but to form these irregular
domes, composed of so many stories; to distribute in a convenient,
yet varied manner, the apartments they include, and to seize the
most favourable time for their labours, but especially to vary them
according to circumstances; to profit by the _points d’appui_ that may
present themselves; and to judge of the advantage of such and such
operations, is it not necessary they should be endowed with faculties
closely approaching intelligence, and that, far from considering them
as automatons, Nature allows them to perceive the intention of those
labours in which they have been engaged?[9]
[9] For several curious particulars relative to the instinct of
insects, I refer to the _Introduction to Entomology, by Messrs.
Kirby and Spence_, vol. ii. p. 465.--This work I cannot too strongly
recommend to the notice of my readers; since it abounds in a variety of
interesting information, and possesses the no small advantage of being
equally amusing as instructive.--T.
I could readily bring forward numberless examples of the industry of
ants, in still mentioning after what manner several other species
construct their abode; but, not to abuse or weary the patience of my
readers, I shall not enter into a detail of the labours of the Field
Ants, who build little chambers, one above the other, along the stems
of plants, and who can, in time of need, connect grains of sand, by
juxta-position alone, or by the admixture of a little moistened earth;
nor of those of the Sanguine Ant, who are enabled to form from earth,
dry leaves, and other materials, a compact tissue, difficult to break,
and impenetrable to water; nor of those covered galleries, which the
Brown Ants construct with earth, conducting from their nest to the feet
of trees, and sometimes even to the origin of the branches, for the
purpose of arriving with greater security at the places where they find
their food.
4. ARCHITECTURE OF ANTS THAT FORM THEIR HABITATION IN TIMBER.[10]
[10] “Some ants” says Kirby, “form their nests entirely of the leaves
of trees. One of these was observed by Sir Joseph Banks in New South
Wales, which was formed by glueing together several leaves as large
as a hand. To keep these leaves in a proper position, thousands of
ants united their strength, and if driven away, the leaves spring back
with great violence.” Latreille speaks of an ant which is met with at
Cayenne (_F. bispinosa_) that forms its nest of a great quantity of
down, which it removes from the seeds of a species of the cotton-tree.
Madame Merian, in her “_Insectes de Surinam_,” speaks of an ant,
which, in Tobago, is called the _parasol ant_. They are in the habit
of cutting out circular pieces from the leaves of trees and plants
(in this respect resembling the _apis papaveris_), and carrying them
off to their nest. When thus engaged, they bear some resemblance to
individuals walking with parasols, hence their name. Smeathman informs
us, that one species of the Termites, or what are commonly known
under the name of White Ants (_T. arborum_) builds its nest among the
branches of trees; and we learn from M. de Laubere, that in that part
of Siam which is exposed to inundations, all the ants construct their
habitations in trees.--T.
Is it not a matter of astonishment, that Nature should have given
to insects of the same genus, manners so varied, and an industry
so widely different? Ants furnish us with one of the most striking
examples of this kind. We have just completed a sketch of the several
species of Mason-ants; each building in a different manner, and
offering some striking peculiarities in the style and mode of their
architecture. That of the Fallow-ants is founded upon different
principles, and the industry of those who excavate their dwelling in
wood, has no point of resemblance with that of the species of which
we have lately treated. This tribe of ants includes several species;
and we still observe in their architectural labours very sensible
shades of difference: all these insects enter into the first of the
nine divisions into which Latreille has distributed ants, it includes
the Brown, the Ash-coloured, the Fallow, the Mining, the Sanguine,
the Fuliginous, and the Yellow Ant, &c. These ants possess the same
exterior organs, a similarity of the means employed in constructing
their dwellings, and resemblances in figure, which have occasioned them
to be placed under the same division; their instinct, however, places
them at a considerable distance from each other, plainly showing that
we cannot always form a correct judgment of the manners and customs of
insects from analogy.
The labours of those ants that inhabit trees, or what we may term
Timber Ants, are less open to general observation than those already
described, and have, in consequence, received but little attention from
naturalists.
The ant holding the first rank in this division, is, the Fuliginous,
so called on account of its colour. It is of a shining black, and is
two lines in length; its republics, composed of a great number of
individuals, are less common than those of which we have hitherto
spoken.
Let us figure to ourselves the interior of a tree entirely sculptured
or hollowed out, consisting of numberless stories, more or less
horizontal, whose floors and ceilings are at five or six lines’
distance from each other, and as thin as a card, supported at one time
by vertical partitions, forming an infinity of chambers; at another
time, by a series of small slender columns, allowing us to observe
between them the extent of an almost entire story; the whole, composed
of a blackish, and as it were smoked wood; and we shall have a just
idea of the cities of these ants.
The greater number of the vertical partitions, which divide each story
into compartments, are parallel; they follow the course of the ligneous
layers, and are always concentrical, which gives to their work some
degree of regularity. The floors, generally speaking, are horizontal.
The little columns are from one to two lines in thickness, more or
less round, of a height equal to that of the story they support, larger
above and below than in the middle, a little flattened at the capital
and base, and ranged in regular lines, since they have been worked out
in the parallel partitions. What numerous apartments! What a series
of lodges, halls and corridors do these insects not form by their own
unsupported industry; and what labour in so great an undertaking does
it not cost them!
The wood, in which ants of this species excavate these labyrinths,
takes a blackish hue:--does this arise from the extravasated fluids of
the tree entering into combination with the external air, or from the
emanation of the ants themselves, the odour of which may perhaps have
some influence; or do the layers of wood, exposed by these insects,
undergo any decomposition from combining with the formic acid? I cannot
decide this question; but I rest well assured, that the wood hewn
by these insects, is always blackish externally, and even takes the
same colour internally, provided it be very thin, preserving only its
natural colour when it has any degree of thickness. It appears that the
oak, willow, and other trees in which these ants establish themselves,
equally take these colours. I have often observed several other species
of ants lodged in the interior of trees, but the wood never presented
the same appearance. I have also often noticed at the foot of those
which were inhabited by Fuliginous Ants, a very abundant and blackish
liquid:--to what must this be attributed? The vegetation of these trees
does not appear in the slightest degree affected by the labours of
these insects.
It would be a highly interesting sight, could we observe ants occupied
in carving the wood in which they fix their residence, we might then
learn the origin of the black tint with which it is imbued; but the
labourers of this species working always in the interior of trees, and
desirous of being screened from observation, precludes every hope, on
our part, of following them in their several occupations. I tried every
expedient I could devise to surmount this difficulty; I endeavoured to
accustom these ants to live and work under my inspection, but all my
efforts were unsuccessful; they even abandoned the most considerable
portion of their nest to seek some new asylum, and spurned the honey
and sugar I offered them for nourishment. I was now, of necessity,
limited to the inspection alone of these edifices; but by decomposing
some of the fragments with care, I hoped to acquire some knowledge of
their organization. Here, we perceive horizontal galleries, hidden in
great part by their walls, which follow the circular direction of the
ligneous layers; there, parallel galleries, separated by extremely thin
partitions, having no communication except by a few oval apertures.
Such is the nature of these works, remarkable for their delicacy and
lightness.
In other fragments we notice avenues, opened laterally, including
portions of walls and transverse partitions, erected here and there,
within the galleries, so as to form separate chambers. When the work is
further advanced, we always observe round holes, encased, as it were,
between two pillars, cut out in the same wall. These holes in course of
time become square, and the pillars, originally arched at both ends,
are worked into regular columns by the chisel of our sculptors. This,
then, is the second specimen of their art. This portion of the edifice
will probably remain in this state.
But here are fragments differently wrought, in which these same
partitions, pierced now in every part, and hewn skilfully, are
transformed into colonnades, which sustain the upper stories, and leave
a free communication throughout their whole extent. We can readily
conceive how parallel galleries hollowed out upon the same plan,
and the sides taken down, leaving only from space to space what is
necessary to sustain their ceilings, may form an entire story; but as
each has been pierced separately, the flooring cannot be very level:
this, however, the ants turn to their advantage, since these furrows
are better adapted to retain the larvæ that may be placed there.
The stories constructed in the great roots offer greater irregularity
than those in the very body of the tree, arising, either from the
hardness and interlacing of the fibres, which renders the labour more
difficult, and obliges the labourers to depart from their accustomed
manner, or from their not observing in the extremities of their
edifice the same arrangement as in the centre: whatever it be, we
still find horizontal stories, and numerous partitions. If the work
be less regular, it becomes more delicate; for the ants, profiting by
the hardness and solidity of the material, give to their building an
extreme degree of lightness. I have seen fragments of from eight to ten
inches in length and of equal height, formed of wood as thin as paper,
containing a number of apartments, and presenting the most singular
appearance. At the entrance of these apartments, worked out with so
much care, are very considerable openings; but, in place of chambers,
and extensive galleries, the layers of the wood are hewn in arcades,
allowing the ants a free passage in every direction. These may be
regarded as the gates or vestibules conducting to the several lodges.
Fig. 3. and 4., Pl. I., give but a very imperfect idea of the labours
of these insects. The first represents a fragment taken from the trunk
of an oak inhabited by Fuliginous Ants; the second, a small portion of
their nest, taken from the roots of the same tree. To judge properly of
these fragments, we should place them in every position, we shall then
better observe their singular organization.
The Red Ant, a little larger than the preceding, forms a lodging in
trees, very analagous to the above, but upon a much smaller scale.
Their dwelling consists of stories more or less developed; some divided
into little chambers or lodges, the walls of which are remarkably thin;
others sustained by an infinity of little columns, resembling, in size
and colour, those of which we have already spoken. The wood, however,
is not blackened, as is the case with that excavated by the Fuliginous
Ants, but retains its original colour. It is commonly less hard, and of
the consistence of cork.
But what is most remarkable in the history of Red Ants is, that they
are not only carvers, but even skilful masons. They more frequently
fix their residence in the earth. This is not, however, the only
species that can, in time of need, display more than one talent in this
department. We are about to notice two kinds of ants which also enjoy
this privilege, the Ethiopian and the Yellow Ant. They have also an art
peculiar to them, of which I have not yet treated, and which must be
regarded as belonging to the architecture of ants.
5. ARCHITECTURE OF THOSE ANTS THAT FORM THEIR RESIDENCE OF SAW-DUST,
DECAYED TIMBER, &C.
The Ethiopian Ants, thus named, on account of their jet-black colour,
hollow out extensive lodges and long galleries in the oldest trees; but
if their works are proportioned to their size, which is greater than
that of other ants, they scarcely represent the infancy of the art by
the manner in which they are executed. What is most remarkable in their
industry is, the use they make of the wood fallen into powder at the
foot of the tree they inhabit, to stop up every chink in the flooring
of their houses, to close useless passages, and to make compartments in
those labyrinths which are too spacious.
The Yellow, one of the mason ants, shows great skill in the employment
of this substance, when it establishes its residence in a hollow tree;
it constructs entire stories with decayed wood, selecting the finest
particles, which, on being mixed up at the bottom of the tree with
a little earth and spider’s web, forms a mass of the consistency of
_papier mâché_. This industry recalls to mind that of wasps, as the
labours of the Mason and Timber Ants bring to our recollection those of
the Mason and Timber Bees.
The class of hymenopterous insects, the richest of all in varied
industry, in original manners and customs, in curious instinct, offers,
continually, similarities and contrasts; connections between genera the
farthest removed, and striking differences between species the most
approximate. The moral condition of these insects does not appear to
follow their physical condition; a truth of some importance to animal
physiology.
CHAP. II.
OF THE EGGS, LARVÆ, AND PUPÆ OF ANTS.
The exterior of ant-hills, their form and construction, have hitherto
entirely occupied us: it was, however, necessary to commence by
establishing the ants in their abode previous to describing the
rest of their labours. The object which will now evidently create
some interest, is that solicitude the workers evince for the object
of their charge, and the maternal attention they bestow upon them
from the period of their quitting the egg to that of their complete
developement.[1] Although several naturalists have studied the
metamorphosis of ants, and described the principal circumstances
connected with it, yet we are about to examine, under new relations,
the developement and education of these insects in their different
states. The history of the egg had entirely escaped their researches,
as well as several particulars in the history of the pupæ and larvæ.
[1] It would be perhaps more regular to speak of the fecundation of
ants, before making known the care and affection they evince for their
young. This plan, from which we could not well depart, in speaking of
insects that lead a solitary life, is not so natural, when treating
of numerous and permanent republics, such as those of ants. It would
have been difficult to have mentioned every circumstance connected
with the reproduction of the species, before describing the interior
of their habitations, and the method I found the most successful in
my observations. The education of their young, being the chief end of
all their labours, offers, in part, a picture of the manners of these
industrious insects. It is for this reason, the plan I now follow
appeared the best to elucidate subsequent remarks.--A.
My predecessors, not having made use of a glazed apparatus to observe
what passed in the interior of ant-hills, had but very rarely seen
these insects engaged in their household occupations; and this was not
so easy of accomplishment as it at first appeared.
These insects, although possessing so little timidity, and regardless,
as it concerns themselves, of the several changes in the weather,
evince the greatest concern for their little ones. For beings,
so delicately formed, they dread the slightest variations of the
atmosphere, are alarmed at the least danger which threatens them, and
seem particularly anxious to withdraw them from our notice.
I was in my first attempts continually disappointed, from the great
repugnance they manifested in allowing the light to penetrate their
abode: whenever I attempted to glaze their apartments, or to lay open
to view any of their halls or passages, if they did not completely
abandon them, they at least prevented me from following them in their
in-door labours. At one time they would darken, by a heap of different
materials, all the halls which admitted the light; at another time, as
if conscious that the glass, notwithstanding its transparency, could
guard them from the external air, and that nothing was wanting to
render it a true wall, but the power of excluding that glaring light,
at all times so disagreeable to them, they preserved entire all the
galleries contiguous to it, taking the sole precaution of covering
it over with a layer of moistened earth, which effectually hindered
further observation.
Thus disappointed, I employed a method more simple, though more
effectual:--I removed a portion of the ant-hill, and then placed over
the remainder a thin flat board inclined to the south; the ants,
attracted by the heat brought their little ones to this place. By
removing this outside shutter or _contrevent_, I could ascertain the
progress in their growth, although the workers, on being disturbed,
hastened to convey them to their under-ground quarters.