MINOTAURUS TYPHŒUS: THE BURROW
To describe the insect which forms the subject of this chapter,
scientific nomenclature has combined two formidable names: that of the
Minotaur, Minos’ Bull fed on human flesh in the windings of the Cretan
labyrinth, and that of Typhon or Typhœus, one of the giants, sons of
Terra, who attempted to scale heaven. Thanks to the clue of thread
which he received from Minos’ daughter Ariadne, Theseus the Athenian
found the Minotaur, slew him, and came out safe and sound, after
delivering his country for ever from the dreadful tribute destined for
the monster’s food.
Typhœus, struck by a thunder-bolt on his piled-up mountains, was hurled
into the flanks of Etna. He is still there. His breath is the smoke of
the volcano. When he coughs, he spews forth streams of lava; when he
shifts his weight from shoulder to shoulder, he puts all Sicily in a
flutter: he shakes her with an earthquake.
It is not unpleasing to find an echo of these old fables in natural
history. Mythological names, so resonant and grateful to the ear, do
not entail any contradiction with reality, a defect not always avoided
by terms entirely built up of data derived from the lexicon. When,
moreover, vague analogies connect the fabulous with the historical,
then the happiest surnames and forenames are obtained. Minotaurus
Typhœus Lin. is an instance in point. It is the name given to a
fair-sized black Beetle, closely related to the earth-borers, the
Geotrupes. [35] This is a peaceable, inoffensive creature, but even
better provided with horns than Minos’ Bull. None among our
armour-loving insects wears so threatening a panoply. The male carries
on his corselet a bundle of three sharp spears, parallel and pointed
forwards. Imagine him the size of a Bull: Theseus himself, if he met
him in the fields, would not dare to face his terrible trident.
The Typhœus of the legend had the ambition to sack the home of the gods
by stacking one atop of the other a pile of mountains wrenched from
their base; the Typhœus of the naturalists does not climb: he descends;
he bores the soil to enormous depths. The first, with a heave of the
shoulder, set a province trembling; the second, with a thrust of his
back, makes his little mound quake as Etna quakes when he who lies
buried beneath her stirs.
Such is the insect which I propose to study to-day, penetrating as far
as may be into the secret sources of its actions. The few particulars
which I have already gained, during the long period of my acquaintance
with it, make me suspect habits worthy of a fuller record.
But what is the use of this record, what the use of all this minute
research? I well know that it will not bring about a fall in the price
of pepper, a rise in that of crates of rotten cabbages or other serious
events of this sort, which cause fleets to be manned and set people
face to face intent upon exterminating one another. The insect does not
aspire to so much glory. It confines itself to showing us life in all
the inexhaustible variety of its manifestations; it helps us to
decipher in some small measure the obscurest book of all, the book of
ourselves.
Insects are easy to obtain, by no means burdensome to feed and not
repulsive when subjected to a physical examination; and they lend
themselves far better than the higher animals to our curious
investigations. Besides, the others are our near kinsfolk and do but
repeat a somewhat monotonous theme, whereas insects, with their
unparalleled wealth of instincts, habits and structure, reveal a new
world to us, much as though we were conferring with the natives of
another planet. This is why I hold insects in such high esteem and
constantly renew my untiring relations with them.
Minotaurus Typhœus affects the open sandy places where the flocks of
Sheep, on their way to the pasture, scatter their trails of black
pellets, which constitute his daily food. In their absence, he also
accepts the tiny products of the Rabbit, which are easy to gather, for
the timid rodent, perhaps afraid of scattering broadcast the evidences
of his whereabouts, always goes to some accustomed spot surrounded by
tufts of thyme, to deposit his droppings.
These to the Minotaur represent victuals of inferior quality, utilized,
in the absence of anything better, for his own nourishment, but not
served to his family. He prefers those supplied by the flock. Were it a
matter of naming him according to his tastes, we should have to call
him the assiduous collector of Sheep-droppings. This pastoral
predilection did not escape the old observers, one of whom speaks of
him as the Sheep Scarab, Scarabæus ovinus.
The burrows, which may be recognized by the little mound that surmounts
them first become numerous in autumn, when the rains have at last come
to moisten the soil parched by the scorching heat of summer. Then the
young of this year emerge slowly from underground and for the first
time come out to enjoy the light; then, for a few weeks, they feast in
temporary marquees; and next they begin to hoard with a view to the
winter.
Let us inspect the dwelling: an easy task, for which a simple
pocket-trowel will suffice. The mansion occupied in the late autumn is
a shaft as wide as a man’s finger and about nine inches deep. There is
no special chamber, but a sunk pit, as perpendicular as the
inequalities of the soil will allow it to be. The owner, now of one
sex, now of the other, is at the bottom, always alone. The time to
settle down and establish a family not having yet arrived, each of them
lives like an anchorite and thinks only of his own welfare. Above the
hermit a vertical column of Sheep-droppings blocks the dwelling. There
is often enough to fill the palm of one’s hand.
How did the Minotaur acquire so much wealth? He amasses it easily,
being spared the worry of seeking it, for he is always careful to
install himself near a copious defecation. He gleans on the very
threshold of his door. When he thinks fit, especially at night, he
chooses from the heap of pellets one to suit him. Using his clypeus as
a lever, he loosens it below; rolling it gently, he brings it to the
orifice of the pit, where the booty is swallowed up. More follow, one
by one, all easily handled because of the olive-like shape. They roll
like casks trundled by the cooper.
When the Sacred Beetle proposes to go banqueting underground far from
the madding crowd, he packs his share of victuals into a ball; he gives
it its spherical form, that best adapted to transport. The Minotaur,
though also versed in the mechanics of rolling, has no occasion to make
these preparations: the Sheep saves him the trouble by modelling
fragments which are easily moved.
At last, satisfied with his harvest, the gleaner goes indoors. What
will he do with his treasure? Feed on it, that goes without saying,
until the cold and its consequent torpor stay the appetite. But eating
is not everything. In the winter, certain precautions become essential
in a retreat of only middling depth. When December draws nigh, already
we find a few mounds as large as those of spring. They correspond with
burrows running down three feet or more. In these deeply buried crypts
there is always a female who, sheltered from the rough weather outside,
is frugally nibbling at her scanty provender.
Dwellings like these, with an equable temperature, are still rare. The
majority, always occupied by a single inhabitant, whether male or
female, are barely nine inches deep. As a rule, they are padded with a
thick blanket, obtained from dry pellets, crumbled and reduced to
shreds. We may take it that this fibrous mass, which is eminently
fitted to retain the heat, has a good deal to do with the hermit’s
comfort in severe weather. In the late autumn, the Minotaur hoards so
that he may take refuge in a felt mattress when the cold really sets
in.
Couples addicted to nest-building in concert begin to meet in the early
days of March. The two sexes, hitherto isolated in burrows near the
surface, are now associated for a long time to come. Where does the
meeting take place, where is the agreement to collaborate concluded?
One fact, to begin with, attracts my attention. At the end of autumn,
as in winter, females abound as frequently as the males. When March
comes, I find hardly any, so much so that I despair of properly
stocking the cage in which I propose to observe the insects’ habits. To
fifteen males I unearth three females at most. What has become of the
latter, so numerous in the beginning?
True, I am excavating the burrows most readily accessible to my
pocket-trowel. Perhaps the secret of the absentees lies at the bottom
of those retreats which are more difficult to inspect. Let us appeal to
arms, suppler and stronger than my own; let us take a spade and dig
deep into the soil. I am rewarded for my perseverance; Females are
found at last, as many as I could wish. They are alone, without
provisions, at the bottom of a perpendicular gallery whose depth would
discourage any one not endowed with exemplary patience.
Everything is now explained. From the time of the spring awakening and
even sometimes at the end of autumn, before they have made the
acquaintance of their collaborators, the valiant future mothers set to
work, choosing a good place and sinking a shaft which, if it does not
yet attain the requisite depth, will at least be the starting-point of
more considerable works. It is in these shafts, more or less advanced,
that the suitors come in search of the workers, at the secret hours of
the twilight. Sometimes there are several of them. It is not uncommon
to find two or three gathered round the same bride. As one is enough,
the others decamp and pursue their quest elsewhere, as soon as the
lady’s choice and perhaps a bit of a skirmish have concluded the
matter.
The quarrels among these pacific creatures cannot be very serious. A
little grappling with the legs, whose toothed shanks grate upon the
rigid harness; a few tumbles provoked by blows of the trident: the
strife amounts to no more than this. When the superfluous wooers are
gone, the pairing takes place, the household is established; and then
and there bonds are contracted which are remarkably enduring.
Are these bonds never dissolved? Do the husband and wife recognize each
other among their fellows? Are they mutually faithful? Cases of
connubial disloyalty are very rare, are in fact unknown, on the part of
the mother, who has long ceased to leave the house; on the other hand,
they are frequent on the part of the father, whose duties often compel
him to go abroad. As we shall see presently, he is throughout his life
the purveyor of victuals, the person appointed to cart away the
rubbish. Single-handed, at different hours of the day, he shoots out of
doors the earth thrown up by the mother’s excavations; single-handed he
explores the surroundings of the house at night, in quest of pellets
whereof to knead the children’s loaves.
Sometimes two burrows are side by side. May not the collector of
provisions, on returning home, easily mistake the door and enter
another’s house? On his walks abroad, does he never happen to meet
ladies taking the air who have not yet settled down and then, forgetful
of his first mate, does he not qualify for divorce? The question was
worth looking into. I have tried to solve it in the following manner.
I take two couples from the ground when the excavations are in full
swing. Indelible marks, scratched with a needle on the lower edge of
the wing-cases, will enable me to distinguish them one from the other.
The four objects of my experiment are distributed at random, singly,
over the surface of a sandy space some eighteen inches deep. Soil of
this depth will be sufficient for the excavations of a night. In case
provisions should be needed, I supply a handful of Sheep-droppings. A
large earthenware pan, turned upside down, covers the arena, prevents
escape and affords the darkness favourable to peaceful concentration.
Next day, I obtain splendid results. There are two burrows in the
settlement and no more; the couples have formed again as they were:
each Jack has recovered his Jill. A second experiment, made next day,
and yet a third meet with the same success: the marked couples are
together, those not marked are together, at the bottom of the shaft.
Five times more, day after day, I make them set up house anew. Things
now begin to go amiss. Sometimes each of my four subjects settles down
apart from the rest; sometimes the same burrow contains the two males
or the two females; sometimes the same vault receives the two sexes,
but associated otherwise than in the beginning. I have repeated the
experiment too often. Henceforth, disorder reigns. My daily shufflings
have demoralized the diggers; a crumbling house that has constantly to
be begun afresh has put an end to lawful unions. Respectable married
life becomes impossible from the moment when the house falls in from
day to day.
No matter: the first three experiments, made when scares, time after
time renewed, had not yet tangled the delicate connecting thread, seem
to point to a certain constancy in the Minotaur’s household. The male
and female recognize each other, find each other in the confusion of
events which my mischievous doings force upon them; they exhibit a
mutual fidelity, a very unusual quality in the insect class, which is
but too prone to forget its matrimonial obligations.
How do they recognize each other? We recognize one another by our
facial features, which vary so greatly in different individuals,
notwithstanding their common likeness. They, to tell the truth, have no
faces; there is no expression beneath their rigid masks. Besides,
things happen in profound darkness. The sense of sight therefore does
not count at all.
We recognize one another by our speech, by the tone, the inflection of
our voices. They are dumb, deprived of all means of vocal appeal. There
remains the sense of smell. Minotaurus finding his mate makes me think
of my friend Tom, the house-dog, who, when the moon stirs his emotions,
lifts his nose in the air, sniffs the breeze and jumps the
garden-walls, eager to obey the remote and magical summons; he puts me
in mind of the Great Peacock Moth, [36] who hastens from miles afield
to pay his respects to the newly-hatched maid.
The comparison, however, is far from being complete, the Dog and the
big Moth get wind of the wedding before they know the bride. The
Minotaur, on the contrary, has no experience of long pilgrimages and
makes his way, within a short radius, to her whom he has already
frequented; he recognizes her, he distinguishes her from the others by
certain emanations, certain individual secrets inappreciable to any
save the enamoured swain. Of what do these effluvia consist? The insect
did not tell me; and that is a pity, for it might have taught us things
worth knowing about its powers of smell.
Now how is the work divided in this household? To discover this is no
easy undertaking, for which the point of a penknife will suffice. He
who proposes to inspect the burrowing insect in its home must resort to
exhausting excavations. We have not here the chamber of the Sacred
Beetle, the Copris or other Beetles, which is uncovered without trouble
with a mere pocket-trowel; we have a shaft whose floor can be reached
only with a stout spade, manfully wielded for hours at a stretch. And,
if the sun be at all hot, you return from your drudgery, feeling
utterly worn out.
Oh, my poor joints, grown rusty with age! To suspect the existence of a
beautiful problem underground and to be unable to dig! The zeal
survives, as ardent as in the days when I used to demolish the spongy
slopes beloved of the Anthophoræ; [37] the love of research has not
abated; but my strength fails me. Fortunately I have an assistant in
the person of my son Paul, who lends me the vigour of his wrists and
the suppleness of his back. I am the head, he is the arm.
The rest of the family, including the mother—and she not the least
eager—usually go with us. You cannot employ too many eyes when the pit
becomes deep and you have to observe from a distance the tiny objects
unearthed by the spade. What one overlooks another will detect. Huber,
[38] when he was blind, studied the Bees through the intermediary of a
clear-sighted and devoted helper. I am even better off than the great
Swiss naturalist. My sight, which is still fairly good though much
worn, is assisted by the perspicacious eyes of all my family. I owe it
to them that I am able to continue my research-work: let me thank them
here and now.
We are on the spot early in the morning. We find a burrow with a large
mound formed of cylindrical plugs forced out as though by blows of the
hammer. We clear away this hillock and a pit opens below it. A good,
long reed, gathered on the way, is inserted in the hole. Pushed farther
home, as the surface soil is cleared away, it will serve us as a guide.
The soil is quite loose, unmixed with pebbles, which are obnoxious to
the digging insect that loves the perpendicular and especially
obnoxious to the cutting edge of the exploring spade. It consists
solely of sand cemented with a little clay. The digging would therefore
be easy, if one had not to reach depths in which tools become extremely
difficult to handle unless the whole area is overturned. The following
method gives good results without unduly increasing the volume of earth
removed, a procedure to which the owner might object.
A space of roughly a yard in radius is attacked around the shaft. As
the guiding reed is laid bare, we push it lower in. It began by going
about nine inches underground, it is now eighteen inches down. Soon it
becomes impracticable to remove the earth with the spade, which is
hampered by lack of room. We have to go on our knees, collect the
rubbish in both hands and toss it outside. The more we do so, the
deeper the hole becomes, increasing the already enormous difficulty. A
moment arrives when, to continue, we are obliged to lie flat on our
stomachs and dip the front of our bodies into the hole, as far as our
more or less supple waists allow. Each dip flings up a good handful of
earth. And the reed goes lower and lower, without giving any indication
of an immediate check.
It is impossible for my son to continue in this fashion, despite his
youthful elasticity. To reach the bottom of the disheartening cavity,
he lowers the level of the sustaining soil. A cut is made at one side
of the circular pit, giving just enough space to admit his two knees.
This is a shelf, a ledge, which will be lowered as we go on. The work
is resumed, this time more actively; but the reed, when we consult it,
descends, descends to a great depth.
We lower the supporting shelf still more and employ the spade again.
When the rubbish is removed, the excavation is more than three feet
deep. Are we there at last? Not at all: the terrible reed dives still
lower down. Let us sink the ledge again and continue. Perseverance is
rewarded. At four feet and a half, the reed touches the obstacle; it
goes no farther. Victory! The task is done: we have reached the
Minotaur’s chamber.
The pocket-trowel discreetly lays it bare and the occupants appear:
first the male, and, a little lower down, the female. When the couple
are removed, a dark, circular patch is seen: this is the top of the
column of provisions. Let us be careful: dig gently! What we have to do
is to cut away the central clod at the bottom of the pit, to separate
it from the surrounding earth and then, slipping the trowel underneath
and using it as a lever, to extract the block all in a lump. There!
That’s done! We have the couple and their nest. A morning of arduous
digging has procured us these treasures: Paul’s broiling back can tell
us at the cost of what efforts.
This depth of nearly five feet is not and could not be uniform: there
are many causes that induce it to vary, such as the degree of moisture
and consistency in the soil traversed, the insect’s passion for work
and the time available, according to the more or less remote date of
the egg-laying. I have seen burrows dip a little deeper; I have seen
others reach not quite three feet. In any case, Minotaurus, to settle
his family, requires a lodging of extravagant depth, such as is dug by
no other burrower of my acquaintance. Presently we shall have to ask
ourselves what imperious needs oblige the collector of Sheep-droppings
to dwell at such depths.
Before leaving the spot, let us note a fact whose evidence will be of
value later. The female was right at the bottom of the burrow; above
her, at some distance, was the male: both were struck motionless with
fright in the midst of an occupation whose nature we are as yet hardly
able to specify. This detail, observed repeatedly in the different
burrows dug up, seems to show that each of the two fellow-workers has a
definite place.
The mother, more skilled in nursery matters, occupies the lower floor.
She alone digs, versed as she is in the properties of the
perpendicular, which economizes labour while giving the greatest depth.
She is the engineer, always in touch with the working-face of the
shaft. The other is her labourer. He is stationed in the rear, ready to
load the rubbish on his horny hod. Later, the excavatrix becomes a
baker: she kneads the cakes for the children into cylinders; the father
is then the baker’s boy. He brings her from outside the wherewithal for
making flour. As in every well-regulated household, the mother is
minister of the interior, the father minister of the exterior. This
would explain the invariable position in their cylindrical home. The
future will tell us if these conjectures truly correspond with the
reality.
For the moment, let us examine at our leisure, in the comfort of our
own home, the central clod, so laboriously acquired. It contains a
preserved foodstuff in the shape of a sausage nearly as long and as
thick as a man’s finger. This is composed of a dark, compact material,
arranged in layers, which we recognize as the Sheep-pellets reduced to
small crumbs. Sometimes the dough is fine and almost homogeneous from
one end of the cylinder to the other; more often the piece is a sort of
hardbake, in which large fragments are held together by an amalgamation
of cement. The baker apparently varies the more or less careful
composition of her confectionery according to the time at her disposal.
The stuff is tightly packed into the closed end of the burrow, where
the walls are smoother and more elaborately treated than in the rest of
the shaft. The point of the knife easily rids it of the surrounding
earth, which peels off like a rind. In this way I obtain the
food-cylinder free from any earthy stain.
When this is done, let us enquire into the matter of the egg, for this
pastry has certainly been manipulated for the sake of a grub. Guided by
what I learnt in the old days from the Geotrupes, who lodge the egg at
the lower end of their black-pudding, in a special recess contrived in
the very heart of the provisions, I look to find the egg of the
Minotaur, their near kinsmen, in a hatching-chamber right at the bottom
of the sausage. I am mistaken. The egg sought for is not at the spot
anticipated, nor at the other end, nor in any part whatsoever of the
victuals.
A search outside the provisions reveals it me at last. It is below the
food, in the sand itself, and has benefited by none of the meticulous
cares wherein mothers excel. There is here not a smooth-walled chamber,
such as the delicate skin of the new-born larva would seem to demand,
but a rough, irregular cavity, the result of a mere falling in rather
than of material ingenuity. The grub is to be hatched in this rude
crib, at some distance from its provisions. To reach the food, it will
have to demolish and pass through a ceiling of sand some millimetres
thick. As regards her offspring, the Minotaur mother is an expert in
the art of sausage-making, but she knows nothing at all of the
endearments of the cradle.
Anxious to watch the hatching and observe the growth of the larva, I
install my find in cells reproducing as nearly as may be the natural
conditions. A glass tube closed at one end of the same diameter as the
burrow receives first a bed of moist sand to represent the original
soil. On the surface of this layer I place the egg. A little of the
same sand forms the ceiling through which the new-born grub must pass
to reach the provisions. There are none other than the regulation
sausage, rid of its earthy rind. A few careful strokes of the rammer
make it occupy the available space. Lastly, a plug of wet, but not
dripping cotton-wool fills up the cell completely. This will be a
source of permanent moisture, similar to that of the depths in which
the mother establishes her family. The provisions will thus remain
soft, in accordance with the youthful consumer’s needs.
This softness of the food and the flavour produced by the fermentation
due to moisture probably have something to say to the instinct to bore
deeply at the time of egg-laying. What do the father and mother really
want? Do they dig to ensure their own welfare? Do they go so low down
in order to find an agreeable temperature and moisture when the fierce
summer heat prevails? Not at all. Endowed with a robust constitution
and loving the sun’s kisses as other insects do, they both inhabit,
until the family is founded, a modest dwelling in a convenient
position. Not even the inclemencies of winter drive them to seek a
better shelter.
At nesting-time it is another matter. They descend to a great depth
underground. Why? Because their family, which is hatched about June,
must find soft food awaiting it at a time when the heat of summer will
bake the soil hard as a brick. The tiny sausage, if it lay at a depth
of ten or twenty inches, would become hard as horn and uneatable; and
the grub, incapable of biting into the tough ration, would perish. It
is important therefore that the victuals should be cellared at a depth
where the most violent heat of the sun cannot lead to desiccation.
Many other food-packers know the risks of excessive dryness. Each has
his own method of warding off the danger. The Geotrupes makes his home
under the voluminous heap dropped by the Mule, an excellent obstacle to
speedy desiccation. Besides, he works in autumn, the season of frequent
showers; moreover, he gives his product the shape of a big roly-poly,
of which the middle part, the only part used, gives up its moisture
very slowly. For these several reasons, he digs burrows of medium
depth.
The Sacred Beetle likewise attaches no value to remote retreats. He
houses his offspring in vaults at no great distance from the surface of
the soil; but he makes amends by fashioning the victuals into a ball:
he knows that round tins keep their contents moist. The Copris does
very much the same with his ovoids. So with the others, the Sisyphus,
[39] the Gymnopleurus. [40] The Minotaur alone takes an enormous dive
underground.
There are different reasons that call for this. Here is a second, more
imperious even than the first. The dung-workers all go for recent
materials, fully endowed with their toothsome and plastic qualities. To
this system of baking the Minotaur makes a stronger exception: what he
needs is old, dry, arid stuff. I have never seen him, either in my
cages or in the open country, gather pellets quite recently ejected. He
wants them dried by long exposure to the sun’s rays.
But, to suit the grub, the hard food has to simmer for a long time and
to improve by keeping, in surroundings saturated with moisture. So the
coarse whole-meal bread is replaced by the bun. The laboratory in which
the children’s food is prepared must therefore be a very deep-seated
factory, which can never be entered by the drought of summer however
long prolonged. Here succulence and flavour are imparted to dry
materials which no other member of the stercoral guild thinks of
employing, for lack of an annealing-chamber, of which Minotaurus
possesses the monopoly. And, the better to fulfil his mission in life,
he also possesses an instinct to bore to enormous depths. The nature of
the victuals makes an incomparable well-sinker of the three-pronged
Dung-beetle; his talents have been determined by a hard crust.