TERMITES.
THE habits of the Termites, or so-called White Ants, have not been so
closely studied as they deserve. Our chief knowledge concerning them is
derived from the observations of Jobson, in his 'History of Gambia;'
Bastian, in 'The Nations of Eastern Asia;' Forsteal, Lespès, König,
Sparman, Hugen, Quatrefages, Fritz Müller, and most of all, Smeathman,
in 'Philosophical Transactions,' vol. lxxi. In Africa these insects
raise their hills to a height of between ten and twenty feet, and
construct them of earth, stones, pieces of wood, &c., glued together by
a sticky saliva. The hills are in the form of a cone, and so strong that
it is said the buffaloes are in the habit of using them as watch-towers
on which to post sentries, and that they will even support the weight of
an elephant. The growth of these gigantic mounds is gradual, increasing
with the increase of the population. From the mound in all directions
there radiate subterranean tunnels, which may be as much as a foot in
width, and which serve as roadways. Besides these tunnels there are a
number of other subterranean tubes, which serve the purpose of drainage
to carry off the floods of water to which the nest is exposed during
tropical showers. Büchner calculates that a pyramid built by man on a
scale proportional to his size would only equal one of these nests if it
attained to the height of 3,000 feet. The following is this author's
description of the internal structure:--
These internal arrangements are so various and so
complicated that pages of description might be written
thereupon. There are myriads of rooms, cells,
nurseries, provision chambers, guard-rooms, passages,
corridors, vaults, bridges, subterranean streets and
canals, tunnels, arched ways, steps, smooth inclines,
domes, &c., &c., all arranged on a definite, coherent,
and well-considered plan. In the middle of the
building, sheltered as far as possible from outside
dangers, lies the stately royal dwelling, resembling
an arched oven, in which the royal pair reside, or
rather are imprisoned; for the entrances and outlets
are so small, that although the workers on service can
pass easily in and out, the queen cannot; for during
the egg-laying her body swells out to an enormous
size, two or three thousand times the size and weight
of an ordinary worker. The queen, therefore, never
leaves her dwelling, and dies therein. Round the
palace, which is at first small, but is later enlarged
in proportion as the queen increases in size until it
is at least a yard long and half a yard high, lie the
nurseries, or cells for the eggs and larvæ; next these
the servants' rooms, or cells for the workers which
wait on the queen; then special chambers for the
soldiers on guard, and, between these, numerous
store-rooms, filled with gums, resins, dried
plant-juices, meal, seeds, fruits, worked-up wood, &c.
According to Bettziech-Beta, there is always in the
midst of the nest a large common room, which is used
either for popular assemblies or as the meeting and
starting point of the countless passages and chambers
of the nest. Others are of the opinion that this space
serves for purposes of ventilation.
Above and below the royal cell are the rooms of the
workers and soldiers which are specially charged with
the care and defence of the royal pair. They
communicate with each other, as well as with the
nursery-cells and store-rooms, by means of galleries
and passages which, as already said, open into the
common room in the middle under the dome. This room is
surrounded by high, boldly projected arched ways,
which lose themselves further out in the walls of the
countless rooms and galleries. Many roofs outside and
in protect this room and the surrounding chambers from
rain, which, as already said, is drained away by
countless subterranean canals, made of clay and of a
diameter of ten or twelve centimetres. There are also,
under the layer of clay covering the whole building,
broad spirally winding passages running from below to
the highest points, which communicate with the
passages of the interior, and apparently, as they
mainly consist of smooth inclines, serve for carrying
provisions to the higher parts of the nest.[71]
The termites, like many species of true ants, are divided into two
distinct castes, the workers and the soldiers. If a breach is made in
the walls of the dome the soldiers rush out to meet the enemy, and fight
desperately with any enemy that they may find. Here, again, I cannot do
better than quote Büchner's epitome of facts:--
If the assailant withdraws beyond their reach and
inflicts no further injury, they retire within their
dwelling in the course of half an hour, as though they
had come to the conclusion that the enemy who had done
the mischief had fled. Scarcely have the soldiers
disappeared when crowds of workers appear in the
breach, each with a quantity of ready-made mortar in
its mouth. As soon as they arrive they stick this
mortar round the open place, and direct the whole
operation with such swiftness and facility that in
spite of their great number they never hinder each
other, nor are obliged to stop. During this spectacle
of apparent restlessness and confusion the observer is
agreeably surprised to see arising a regular wall,
filling up the gap. During the time that the workers
are thus busied the soldiers remain within the nest,
with the exception of a few, which walk about
apparently idly, never touching the mortar, among the
hundreds and thousands of workers. Nevertheless one of
them stands on guard close to the wall which is being
built. It turns gently each way in turn, lifting its
head at intervals of one or two minutes to strike the
building with its heavy mandibles, making the
before-mentioned crackling noise. This signal is
immediately answered by a loud rustling from the
interior of the nest and from all the subterranean
passages and holes. There is no doubt that this noise
arises from the workers, for as often as the sign is
given they work with increased energy and speed. A
renewal of the attack instantaneously changes the
scene. 'At the first stroke,' says Smeathman, 'the
workers run into the many tunnels and passages which
run through the building, and this happens so quickly
that they seem regularly to vanish. In a few seconds
they are all gone, and in their stead appear the
soldiers once more, as numerous and as pugnacious as
before. If they find no enemy, they turn back slowly
into the interior of the hill, and immediately the
mortar-laden workers again appear, and among them a
few soldiers, which behave just as on the first
occasion. So one can have the pleasure of seeing them
work and fight in turn, as often as one chooses; and
it will be found each time that one set never fight,
and the other never work, however great the need may
be.'[72]
Similar facts have been observed by Fritz Müller of the South American
species.
The Termites, being like the Ecitons blind, like them make all their
expeditions under the protection of covered ways. These are underground
tunnels in all cases where circumstances permit, but on arriving at a
rock or other impenetrable obstruction, they build a tubular passage
upon the surface. According to Büchner,--
They can even carry their viaducts through the air,
and that in such bold arches that it is difficult to
understand how they were projected. In order to reach
a sack of meal which was well protected below, they
broke through the roof of the room in which it was,
and built a straight tube from the breach they had
made down to the sack. As soon as they tried to carry
off their booty to a safe place, they became convinced
that it was impossible to pull it up the straight
road. In order to meet this difficulty, they adopted
the principle of the smooth incline, the use of which
we have already seen in the interior of their nests,
and built close to the first tube a second, which
wound spirally within, like the famous clock tower of
Venice. It was now an easy task to carry their booty
up this road and so away. . . . Either from the desire
to remain undiscovered, or from their liking for
darkness, they have the remarkable habit of destroying
and gnawing everything from within outwards, and of
leaving the outside shell standing, so that from the
outside appearance the dangerous state of the inside is
not perceptible. If, for instance, they have destroyed
a table or other piece of household furniture, in which
they always manage from the ground upwards to hit
exactly the places on which the feet of the article
rest, the table looks perfectly uninjured outside, and
people are quite astonished when it breaks down under
the slightest pressure. The whole inside is eaten away,
and only the thinnest shell is left standing. If fruits
are lying on the table, they also are eaten out from
the exact spot on which they rest on the surface of the
table.
In similar fashion things consisting wholly of wood,
such as wooden ships, trees, &c., are destroyed by
them so that they finally break in without any one
having noticed the mischief. Yet it is said that they
go so prudently to work in their destruction that the
main beams, the sudden breakage of which would
threaten the whole building and themselves therewith,
are either spared, or else so fastened together again
with a cement made out of clay and earth that their
strength is greater than ever!(?) Hagen also states
that they never cut right through the corks which stop
up stored bottles of wine, but leave a very thin
layer, which is sufficient to prevent the outflow of
the wine and the consequent destruction of the
workers. The same author relates that in order to
reach a box of wax lights they made a covered road
from the ground up to the second story of a house.[73]
It is needless to give a special description of any of the other habits
of these insects, such as their swarming, breeding, &c., for they all
more or less closely resemble the analogous habits of ants and bees. It
is very remarkable that insects of two distinct orders should both
manifest such closely similar social habits of such high complexity, and
it rather surprises me that more has not been made of this point by
writers opposed to the principles of evolution. Of course if the point
were raised, the argument in answer would require to be, either that the
similar instincts were derived from common and very remote progenitors
(in which case the fact would form by far the most remarkable instance
of the permanency of instincts among changing species), or more
probably, that similar causes operating in the two orders have produced
similar effects--complex and otherwise unique though these effects
undoubtedly are.
In connection with the theory of evolution I may conclude this chapter
with the following quotation from Smeathman, as it shows how natural
relation may develop for the benefit of the species instincts which are
detrimental to the individual. Speaking of the soldiers he says:--
I was always amused at the pugnacity displayed when,
in making a hole in the earthy cemented archway of
their covered roads, a host of these little fellows
mounted the breach to cover the retreat of the
workers. The edges of the rupture bristled with their
armed heads as the courageous warriors ranged
themselves in compact line around them. They attacked
fiercely any intruding object, and as fast as their
front ranks were destroyed, others filled up their
places. When the jaws closed in the flesh, they
suffered themselves to be torn in pieces rather than
loosen their hold. It might be said that this instinct
is rather a cause of their ruin than a protection when
a colony is attacked by the well-known enemy of
termites, the ant-bear; but it is the soldiers only
which attach themselves to the long worm-like tongue
of this animal, and the workers, on whom the
prosperity of the young brood immediately depends, are
left for the most part unharmed. I always found, on
thrusting my finger into a mixed crowd of termites,
that the soldiers only fastened upon it. Thus the
fighting caste do in the end serve to protect the
species by sacrificing themselves to its good.[74]
FOOTNOTES:
[71] _Loc. cit._, p. 189.
[72] _Ibid._, p. 119.
[73] _Geistesleben der Thiere_, pp. 194 and 199-200.
[74] Phil. Trans., _loc. cit._