Cow caterpillars—The adventures of Theophrastus—Cave-born
Ariels—Led to the sky—A strange attraction—Ant slaves and
slave-holders—Slave-making raids—Feeble masters—An ant
mystery—Effects of slavery—The decadent’s reply.
AS we have seen, both in this chapter and a former one, aphides are not
the only insects which yield the ants honey—or something honey-sweet—and
are cherished by them in consequence. There are, for instance, the
coccidæ, or scale insects, as mentioned by Belt; but whilst some of this
family are milked in the same way as the aphides, to which, indeed, they
bear a strong resemblance, others are simply eaten, as though they were
sweets. To them might be said in warning, “Make yourself all honey, and
the _ants_ will swallow you,” but who can modify the nature of his own
juices? Then there are the ants’-nest beetles, many of which have a
sweet downiness which the ants enjoy licking, and are for this reason
carried about with them when they move from one place to another. Not
that they are always carried, for one little beetle, at any rate, whose
name—it must be a diminutive—is _Formicoxenus nitidulus_, is accustomed
to ride on the backs of its protectors, like the little cockroaches
discovered by Professor Wheeler.
But perhaps the most interesting parallel to the aphides, as cows, is to
be found in certain caterpillars, which are as soft and defenceless as
they are, and represent a class of creatures which ants habitually prey
upon. A certain family of butterflies, however, commonly known as the
Blues, but entitled to the scholarly name of _Lycænidæ_, produce
caterpillars which bear, upon the twelfth segment of the body, a certain
honey-holding reservoir which, when full or nearly so, may be made to
yield its contents through the same treatment which is so effectual in
the case of the aphides. The ants tap or titillate the body of the
caterpillar, near where the gland is situated, with their antennæ, and
the caterpillars, charmed with such affability, overflow in return. This
interesting fact has been observed in various parts of the Old World,
and also in North America; but the most detailed account which we have
of it comes from India. In this case, as in all the others, the
caterpillar is a quite small one, and feeds on the leaves of a certain
tree, bearing both “an astringent yellow fruit” and the name of
_Zizyphus jujuba_, though, by the way, jujubes are not, as a rule,
astringent. The name of this little caterpillar—it would scorn to be
behind the tree it feeds on in such a matter—is _Tarucus theophrastus_,
so now we have something to fix it in the memory. The ant that
patronises it is a large black one—_its_ name I cannot give—and here,
too, as in the case of the aphidean relations, we have, in the most
noteworthy of the actions recorded, a very remarkable instance of what
looks like foresight, and foresight, too, of a very large and general
kind. In the first place, the ants make a nest at the foot of the trees
in which the caterpillars reside, and here, during the period of their
growth and nourishment, they avail themselves of their services. But
when this period is over, and the caterpillars are about to change into
chrysalids, then a strange scene takes place. All over the tree, ants
are now to be seen running about in a state of the greatest excitement,
and whenever they meet a caterpillar descending, or preparing to
descend, the trunk, in order to burrow into the earth at its base, and
there pass its pupal stage of existence, they conduct it down themselves
and relieve it from the labour of digging, just in the same way as our
English ants do with the aphides.
Still stranger is the scene which reveals itself if the earth at the
base of the tree be removed, for then it is seen that chrysalids, and
caterpillars that are about to turn into chrysalids, are clinging all
round the trunk, whilst all amongst them are the ants, helping to place
this one or that one in position. The band thus formed round the tree
may be several inches broad, and it is always remarkably even, as though
arranged on æsthetic principles. As the light shines in, the ants become
agitated, and seizing hold of their property—for in this light they
consider the caterpillars—begin to rebury them, so that in time, if the
annoyance continues, they will form a fresh circle of bodies lower down
the tree. Here, then, is an ants’ nest, described as temporary by Mrs.
Wyllie, from whose interesting account[51] the above facts are taken,
full of butterfly chrysalids, and in about a week it becomes full of
butterflies themselves, and amidst the rough, black bodies of hosts of
earth-working Calibans, colours born of the rainbow gleam and flash from
the fairy wings of delicate insect Ariels. Each one of these was helped
from its cradle, thus strangely situated, by a little group of these
gnomes, who then assisted it to unfold its wings, and guided its
uncertain steps. Later, when strength has come to it, and something—it
knows not what—like an upward desire, these same gnomes will lead it to
the portals of their gloomy Hades, where it will spread its wings and
fly to meet the light. In so strange a way, led by such uncouth guides,
does Ariel find the sky. Yet, as though the place of their new
birth—gloomy though it be and opposed to their light-loving natures—had
yet some nameless attraction for them, crowds of these butterflies may
be seen, for some time after their exodus, hovering over the nest,
before they leave it for ever to dwell in the courts of the sun.
Just as in the case of the aphides released by _Lasius fuliginosus_,
these ants will never see their butterflies again, nor will they gain
any after advantage that can with certainty be traced to the particular
individuals thus set free. But they gain in such a manner as, if the
reflection really occurred to them, would make ants not much below men.
The process of reasoning would be this: “Though we may very likely not
get any caterpillars from the eggs which these butterflies will lay, yet
we ought not to kill them, because then there would be so many
butterflies less in the world, to lay eggs, and if we did this every
year, and other ants too, caterpillars, as well as butterflies, would
become scarce, and at last we should not get enough.” For myself I doubt
if ants really do reason like this, but by what steps this habit of
releasing butterflies so as to ensure the perpetuation of the species
has come about, I don’t quite see. In the case of the aphides, perhaps
it has been through actual observation of their habits, and here, too,
this hypothesis may not be excluded, since the butterflies might well be
seen laying their eggs, nor is it unlikely that these are watched, and
the issuing caterpillars tended from the beginning. For the purposes of
the ants, indeed, all aphides, and every theophrastus, would be the
same, and they might very well think that those which they found laying,
or about to lay their eggs, were the very ones previously liberated by
them from the nest. Thus the difficulty involved in supposing that they
must reason in a general and not merely in a particular way does not
really exist.
Some of these black caterpillar-tending ants of India are not always so
lucky as to secure stock. They may live far from a _jujube_ tree, and so
never meet the right species; but if ever they do, even though it be in
the most unexpected manner, they are not taken by surprise,
notwithstanding that other caterpillars are habitually devoured by them.
Mrs. Wyllie proved this by an experiment. “I took Theophrastus,” she
tells us, “from a tree, and introduced him on the pathway of another
company of the same species of ant, which lived in our verandah, but
kept no farm, and it was odd to see the ants come tumbling out headlong
to fight the intruder, and the sudden way in which they cooled down on
investigation of the foe. None attempted to harm him, and he was
politely escorted across the boundary, the ants running alongside and
feeling him all over with their antennæ. This must have been
instinctive, as they could have had no former knowledge of him as a
‘milk-giver.’” Mrs. Wyllie adds that “the dead chrysalids in an ants’
nest are carefully removed and thrown away outside; the ants also
distinguish between the dead and the living.”
Anyone observing or reading about ants might exclaim, on finding that
they utilised the natural product of other insects and kept them in
captivity in order to do so, “Where will this end? May they not, then,
also keep slaves?” And in very fact, as all the world now knows, we do
find what is called slavery amongst ants, though to me it hardly seems
the right word, since there is perfect willingness on the part of the
slave, and no power of punishment lies with the master. There is
equality, moreover, since this is not a matter of the kind of things
which one class of a community does and another does not do, but of the
spirit in which each does them. With the ants we have the Japanese
spirit—or rather the Japanese seem getting nearer to the ants—and so
there is real equality. However, the first act which makes these
creatures slaves—for I will use terms as I find them—is one of violent
and deadly hostility, and through it they are, of set purpose, taken
possession of and carried off to the nest. At that period, however, they
are yet in the cradle, have yet to be born into their last and most
perfect state of life. From the moment they are so born they grow up as
a part, and indeed the most important part, of the body politic, and of
such pleasure and consideration as obtains in ant-life they have their
full share.
From the above it may be gathered that these ant-slaves are ants
themselves, and this, indeed, is the case. One species of ant raids the
nest of another, overpowers the able-bodied inhabitants, slays or
incapacitates a certain number, and carries away with it to its own nest
as many of the helpless pupæ as it is able to. For a great many
years—thousands probably—these combats and carrying off of spoil had
been observed, but it had always been imagined that the pupæ—or ants’
eggs, as they are commonly called—were taken as provisions, merely to be
stored in the nest of the victor, and there eaten at leisure. The
discovery of the real truth was an era in the study of ant-history, and
it was made by a Frenchman—Pierre Huber—a man of whom Darwin says that
he was a “better observer even than his celebrated father,” for Pierre
was the son of François Huber, the blind man, who yet found out all
about bees. I hardly see how he can have been _better_ myself; but the
son was not blind, and, of course, eyesight is an advantage in
observation.
The particular species of ant concerning which this discovery was made
is _Formica rufescens_, or _Polyergus rufescens_—the reader may take his
choice—and Darwin, who impresses the facts of ant-slavery upon the mind
better than a dozen books specially devoted to ants or insects, says of
it: “This ant is absolutely dependent on its slaves, and without their
aid the species would certainly become extinct in a single year. The
males and fertile females do no work of any kind, and the workers, or
sterile females, though most energetic and courageous in capturing
slaves, do no other work. They are incapable of making their own nests
or of feeding their own larvæ. When the old nest is found inconvenient,
and they have to migrate, it is the slaves which determine the
migration, and actually carry their masters (one might just as well call
_them their_ slaves) in their jaws. So utterly helpless are the masters,
that when Huber shut up thirty of them without a slave, but with plenty
of the food which they like best, and with their own larvæ and pupæ to
stimulate them to work, they did nothing; they could not even feed
themselves, and many perished of hunger. Huber then introduced a single
slave, and she instantly set to work, fed and saved the survivors, made
some cells, and tended the larvæ, and put all to rights. What can be
more extraordinary than these well-ascertained facts?”[52] The slave-ant
in this case is _Formica fusca_, and it is also held in bondage by
another species of slave-maker, viz. _Formica sanguinea_—or the
Blood-red Ant—as was likewise a discovery of Pierre Huber. This last
species is found in the south of England, and its slave-making habits
have been observed by Darwin, who opened fourteen nests and found a few
slaves in all of them. “The slaves,” he tells us, “are black, and not
above half the size of their red masters, so that the contrast in their
appearance is great.”[52] The black ants were not often seen by Darwin
to leave the nest, and others who have observed their habits in England
have considered them as “strictly household slaves.”[52] Huber, however,
whose observations were carried on in Switzerland, says that “their
chief office is to search for aphides,”[52] and this would take them far
afield. In Switzerland, however, slaves seem to be more numerous in the
nests of the Blood-red Ant, and Darwin attributes the difference in
their habits to this account. Huber also tells us that the Swiss slaves
“habitually work with their masters in making the nest, and they alone
open and close the doors in the morning and evening.”[52] This is done,
I suppose, by placing pellets of earth in the mouth of the
entrance-tunnel and removing them again; but there is one species of ant
which would have only to place or remove itself, for this purpose, since
its large head, by being wedged into the passage, stops it up, and thus
fulfils the office of a front door. The ant that does this must be one
belonging to a certain caste of workers having very large heads, for the
heads of the other ones would not be large enough. The nest of this
species is made in decaying wood, and there is always some worker who
thus uses his large head as a stopper, removing it when a
fellow-townsman wishes to enter the nest, but presenting its smooth,
impenetrable surface, guarded with jaws, to all unauthorised intruders.
It is Forel, one of the best ant-observers of to-day, who tells us this,
and the ant apparently is _Lasius fuliginosus_, which is a British
species, and, according to an account which I have already referred to,
does not seem to be always a wood-borer. _Formica sanguinea_, however,
does things—or has things done for it—after a more ordinary fashion.
Darwin was the witness of a slave-raid on the part of _F. sanguinea_
which was not, in this instance, very successful. He says: “They
approached, and were vigorously repulsed by an independent community of
the slave-species (_F. fusca_), sometimes as many as three of these ants
clinging to the legs of the slave-making _sanguinea_. The latter
ruthlessly killed their small opponents, and carried their dead bodies
as food to their nest, twenty-nine yards distant; but they were
prevented from getting any pupæ to rear as slaves. I then dug up a small
parcel of the pupæ of _Formica fusca_ from another nest, and put them
down on a bare spot near the place of combat; they were eagerly seized
and carried off by the tyrants, who perhaps fancied that, after all,
they had been victorious in their late combat.”[52] In his work, _Ants
and their Ways_,[53] the Rev. Farren White describes a similar raid
which was—or rather which had been, for it was nearly over when he
arrived on the scene—wholly successful. Here, however, the oppressed
species seems to have made a very poor resistance, though very likely it
had been more vigorous in the earlier stages of the raid. “I watched a
_fusca_,” says Mr. White, “carrying off a pupa from behind the entrance
whence the _sanguineæ_ were issuing forth. Immediately it saw one of the
enemy approaching, it dropped its charge and left it to its fate. The
_sanguinea_ then gave it a push, and drove it off in double-quick time”;
and, again, “I noticed a _sanguinea_ coming up out of the nest with a
pupa, and a _fusca_, observing it, went up a fern-frond with the utmost
expedition.”[53] Other observations of a similar nature were made, and
the conclusion arrived at by Mr. White is “that between the _fuscæ_ and
the _sanguineæ_ there is a well-defined and clearly pronounced
antagonism. In presence of the _sanguineæ_ the _fuscæ_ were
terror-stricken. In fact the depredators had it all their own way, and
were able in this instance, at least, to carry out their marvellous
instincts without destroying a single life.”[53] It will be seen how ill
this accords with the account given by Darwin. My own way of accounting
for the discrepancy is that, in the first instance, the little _fuscæ_
were flushed with success, and, in the second, demoralised through
defeat. The same effects would follow the same causes in all but the
most splendid human armies.
The raids made by the first-mentioned species, _Polyergus rufescens_,
or, as Huber calls them, the Amazon ants, are of an even more determined
description, for none are braver, or perhaps so brave. If one of these
should find herself alone and in the midst of enemies, she makes no
effort to escape, as many, though not all, other species would, but
fights on to the end, making constant agile leaps to this side or that,
at every one of which she transfixes an enemy, and dies at last biting
hard. To fight, indeed, is the whole end, aim, and business of life for
an Amazon, and we have already seen how they do no work, and are washed,
fed, and carried by their servants. It is not quite true, however, that
they cannot feed themselves, as Pierre Huber thought, and had good
reason to think, for a well-known living observer—Herr Wasmann—has
discovered that their mandibles are so constructed as to enable them “to
absorb nourishment from eggs or pupæ.” Possibly the mandibles are
hollow, and communicate thus with the mouth, as is the case with some
other insects, but I have not Wasmann’s account at hand, and his
exponent says only this. Wasmann tells us also that these Amazons will
“absorb nourishment,” however they do it, even from the eggs of their
own species. They cannot, however, feed on liquid food, and as they had
no other when shut up without servants, that is why they died, or would
have died, had these not been brought them in time. So too, though their
slaves wash and brush them, yet they are always brushing themselves and
attending generally to their own toilette, and this they do even amidst
“All the currents of a heady fight,”
so that Wasmann has compared them to the Spartans combing their long
hair before the battle of Thermopylæ, though we are not told that they
combed it after the fight had begun.
Still, it seems plain that the habit of keeping slaves has exercised a
degrading influence on these ants, and this tendency is much more
markedly apparent in several other species. One of these with a really
dreadful name, _Strongylognathus_—we might call them Strong Ants, but
they seem to be weak ones—is described by Forel as “_une triste
caricature_” of the Amazons, and the extraordinary thing is that,
though themselves feeble and enervated, they manage to make, or by
some means obtain as slaves, the workers of a much more robust
species—_Tetramorium_, to wit; workers, by the way, are the only class
of ants ever enslaved. These weak ants fight in the same way as the
Amazons themselves; but, though spirited enough, they are so much
inferior in bodily vigour to the _Tetramoriums_, “a courageous species
living in large communities, that in a battle between the two,
artificially instigated by Forel, almost all the slave-holders were
killed, without being able to avenge their deaths even on a single one
of those whom they aspired to rule.” Yet they won the day, or rather
the already enslaved _Tetramoriums_, who marched to do battle for
them, won it for the few survivors in their ranks. From this we can
see how, when these decadents once have slaves, they may get more. The
difficulty is how they are obtained in the first instance—when a nest
is first founded by a queen of the slave-making species, for example.
It might be supposed, finding two kinds of ants living together, one
weaker and much more helpless than the other, that the former lived a
parasitic existence in the nest of the latter, and was not a
slave-owner at all; but this theory is disproved by the fact that no
males or females of the _Tetramoriums_ are ever to be found, showing
that it is not they but the others who are the true founders of the
nest.
A still more extraordinary instance of a slave-holding species of ant
than the one just mentioned is _Anergates atratulus_, for in this there
are no workers at all, only kings and queens, who are waited on, and
their eggs and larvæ fed and tended, by the slave species—_Tetramorium_,
in this case also—just as though these latter were their true-born
subjects. Here too the slave species is only represented by workers.
These male and female _Anergates_—a worker of the species has never been
known—are both few in number and weak in themselves. When a pair of them
(or a fertilised queen) go off to found a new colony, how do they, or
how do their few weak descendants, impress a strong fierce species into
their service, by whom the nest is built, and every other service
performed? The question remains unanswered. Nobody knows. Several
theories have been advanced, one by Sir John Lubbock, who supposes that
the king and queen of _Anergates_ assassinate the queen of _Tetramorium_
and reign in her stead,[54] and another, more recently, by Wasmann,
whose idea is that fertile queens of _Anergates_ are sometimes adopted
by a colony of _Tetramoriums_ who have lost their own queen. This last
is the newest suggestion, and is considered just at present, perhaps for
that reason, the most probable. To me Sir John Lubbock’s view seems
likelier to be correct, since it is more usual in nature for the weak to
prey, as parasites, upon the strong, than for the strong to seek
assistance of the weak. True, I can form no idea as to how the
assassination of the rightful queen takes place, but Nature is full of
resources, and will do much to promote a really worthy end.
I will conclude this chapter by quoting some remarks of Sir John Lubbock
as to the ill effects which the institution of slavery exercises, with
ants as with men, upon the character of the slave-holder. “These four
genera,” he says, “offer us every gradation from lawless violence to
contemptible parasitism. _Formica sanguinea_, which may be assumed to
have comparatively recently taken to slave-making, has not, as yet, been
materially affected. _Polyergus_, on the contrary, already illustrates
the lowering tendency of slavery. They have lost their knowledge of art
and their natural affection for their young! They are, however, bold and
powerful marauders. In _Strongylognathus_ the enervating influence of
slavery has gone further, and told even on the bodily strength. They are
no longer able to capture their slaves in fair and open warfare. Still,
they retain a semblance of authority, and, when roused, will fight
bravely, though in vain. In _Anergates_, finally, we come to the last
scene of this sad history. We may safely conclude that in distant times
their ancestors lived, as so many ants do now, partly by hunting, partly
on honey; that by degrees they became bold marauders, and gradually took
to keeping slaves; that for a time they maintained their strength and
agility, though losing, by degrees, their real independence, their arts,
and even many of their instincts; that gradually even their bodily force
dwindled away under the enervating influence to which they had subjected
themselves, until they sank to their present degraded condition—weak in
body and mind, few in numbers, and, apparently, nearly extinct, the
miserable representatives of far superior ancestors, maintaining a
precarious existence as contemptible parasites of their former
slaves.”[55]
Since, however, in all these cases the masters are still truly served by
their slaves, who make them comfortable, and have no more sense of their
degradation than they themselves have, an answer might be made to these
moralisings. However various the masks behind which true motives lie
hid, happiness, diversely conceived of, is the one end and aim of all.
Does it, then, really much matter by what means it is attained? Till we
can show that these slave-holding ants have become less and less happy,
we are only tilting at shadows, and an _Anergates_ might very well say,
in regard to the above view, “Tut, prut, drop your heroics. I am very
comfortable; these strong fellows work for me. I like not working, and
what I am I wish to be.”
-----
Footnote 51:
It appeared, I think, originally in the _Bombay Journal_ and is
reproduced in one of the leading entomological magazines.
Footnote 52:
Darwin, Origin of Species, pp. 216, 217, 218.
Footnote 53:
Rev. Farren White, Ants and their Ways, pp. 177-9.
Footnote 54:
Lubbock, Ants, Bees, and Wasps, pp. 87-9.
Footnote 55:
Rev. Farren White, Ants and their Ways, pp. 177-9.
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