To meet among the Wasps, those eager lovers of flowers, a species that
goes hunting more or less on its own account is certainly a notable
event. That the larder of the grub should be provided with prey is
natural enough; but that the provider, whose diet is honey, should
herself make use of the captives is anything but easy to understand. We
are quite astonished to see a nectar-drinker become a blood-drinker. But
our astonishment ceases if we consider things more closely. The double
method of feeding is more apparent than real: the crop which fills
itself with sugary liquid does not gorge itself with game. The Odynerus,
when digging into the body of her prey, does not touch the flesh, a fare
absolutely scorned as contrary to her tastes; she satisfies herself with
lapping up the defensive drop which the grub (The Larva of Chrysomela
populi, the Poplar Leaf-beetle.--Translator's Note.) distils at the
end of its intestine. This fluid no doubt represents to her some
highly-flavoured beverage with which she seasons from time to time
the staple diet fetched from the drinking-bar of the flowers, some
appetizing condiment or perhaps--who knows?--some substitute for honey.
Though the qualities of the delicacy escape me, I at least perceive that
the Odynerus does not covet anything else. Once its jar is emptied,
the larva is flung aside as worthless offal, a certain sign of a
non-carnivorous appetite. Under these conditions, the persecutor of the
Chrysomela ceases to surprise us by indulging in the crying abuse of a
double diet.
We even begin to wonder whether other species may not be inclined to
derive a direct advantage from the hunting imposed upon them for the
maintenance of the family. The Odynerus' method of work, the splitting
open of the anal still-room, is too far removed from the obvious
procedure to have many imitators; it is a secondary detail and
impracticable with a different kind of game. But there is sure to be a
certain variety in the direct means of utilizing the capture. Why, for
instance, when the victim paralysed by the sting contains a delicious
broth in some part of its stomach, should the huntress scruple to
violate her dying prey and force it to disgorge without injuring
the quality of the provisions? There must be those who rob the dead,
attracted not by the flesh but by the exquisite contents of the crop.
In point of fact, there are; and they are even numerous. We may
mention in the first rank the Wasp that hunts Hive-bees, the Bee-eating
Philanthus (P. apivorus, LATR.). I long suspected her of perpetrating
these acts of brigandage on her own behalf, having often surprised her
gluttonously licking the Bee's honey-smeared mouth; I had an inkling
that she did not always hunt solely for the benefit of her larvae. The
suspicion deserved to be confirmed by experiment. Also, I was engaged
in another investigation, which might easily be conducted simultaneously
with the one suggested: I wanted to study, with all the leisure of work
done at home, the operating-methods employed by the different Hunting
Wasps. I therefore made use, for the Philanthus, of the process of
experimenting under glass which I roughly outlined when speaking of the
Odynerus. It was even the Bee-huntress who gave me my first data in this
direction. She responded to my wishes with such zeal that I believed
myself to possess an unequalled means of observing again and again, even
to excess, what is so difficult to achieve on the actual spot. Alas,
the first-fruits of my acquaintance with the Philanthus promised me more
than the future held in store for me! But we will not anticipate; and
we will place the huntress and her game together under the bell-glass.
I recommend this experiment to whoever would wish to see with what
perfection in the art of attack and defence a Hunting Wasp wields the
stiletto. There is no uncertainty here as to the result, there is no
long wait: the moment when she catches sight of the prey in an attitude
favourable to her designs, the bandit rushes forward and kills. I will
describe how things happen.
I place under the bell-glass a Philanthus and two or three Hive-bees.
The prisoners climb the glass wall, towards the light; they go up, come
down again and try to get out; the vertical polished surface is to them
a practicable floor. They soon quiet down; and the spoiler begins to
notice her surroundings. The antennae are pointed forwards, enquiringly;
the hind-legs are drawn up with a little quiver of greed in the tarsi;
the head turns to right and left and follows the evolutions of the Bees
against the glass. The miscreant's posture now becomes a striking piece
of acting: you can read in it the fierce longings of the creature lying
in ambush, the crafty waiting for the moment to commit the crime. The
choice is made: the Philanthus pounces on her prey.
Turn by turn tumbling over and tumbled, the two insects roll upon the
ground. The tumult soon abates; and the murderess prepares to strangle
her capture. I see her adopt two methods. In the first, which is more
usual than the other, the Bee is lying on her back; and the Philanthus,
belly to belly with her, grips her with her six legs while snapping
at her neck with her mandibles. The abdomen is now curved forward from
behind, along the prostrate victim, feels with its tip, gropes about
a little and ends by reaching the under part of the neck. The sting
enters, lingers for a moment in the wound; and all is over. Without
releasing her prey, which is still tightly clasped, the murderess
restores her abdomen to its normal position and keeps it pressed against
the Bee's.
In the second method, the Philanthus operates standing. Resting on her
hind-legs and on the tips of her unfurled wings, she proudly occupies
an erect attitude, with the Bee held facing her between her four
front legs. To give the poor thing a position suited to receive the
dagger-stroke, she turns her round and back again with the rough
clumsiness of a child handling its doll. Her pose is magnificent to look
at. Solidly planted on her sustaining tripod, the two hinder tarsi and
the tips of the wings, she at last crooks her abdomen upwards and
again stings the Bee under the chin. The originality of the Philanthus'
posture at the moment of the murder surpasses the anything that I have
hitherto seen.
The desire for knowledge in natural history has its cruel side. To learn
precisely the point attacked by the sting and to make myself
thoroughly acquainted with the horrible talent of the murderess, I
have investigated more assassinations under glass than I would dare to
confess. Without a single exception, I have always seen the Bee stung
in the throat. In the preparations for the final blow, the tip of the
abdomen may well come to rest on this or that point of the thorax
or abdomen; but it does not stop at any of these, nor is the sting
unsheathed, as can readily be ascertained. Indeed, once the contest is
opened, the Philanthus becomes so entirely absorbed in her operation
that I can remove the cover and follow every vicissitude of the tragedy
with my pocket-lens.
After recognizing the invariable position of the wound, I bend back and
open the articulation of the head. I see under the Bee's chin a white
spot, measuring hardly a twenty-fifth of an inch square, where the horny
integuments are lacking and the delicate skin is shown uncovered. It
is here, always here, in this tiny defect in the armour, that the sting
enters. Why is this spot stabbed rather than another? Can it be the only
vulnerable point, which would necessarily determine the thrust of the
lancet? Should any one entertain so petty a thought, I advise him to
open the articulation of the corselet, behind the first pair of legs.
He will there see what I see: the bare skin, quite as fine as under the
neck, but covering a much larger surface. The horny breast-plate offers
no wider breach. If the Philanthus were guided in her operation solely
by the question of vulnerability, it is here certainly that she ought to
strike, instead of persistently seeking the narrow slit in the neck. The
weapon would not need to hesitate and grope; it would obtain admission
into the tissues off-hand. No, the stroke of the lancet is not forced
upon it mechanically: the assassin scorns the large defect in the
corselet and prefers the place under the chin, for eminently logical
reasons which we will now attempt to unravel.
Immediately after the operation I take the Bee from the Philanthus. What
strikes me is the sudden inertia of the antennae and the mouth-parts,
organs which in the victims of most of the Hunting Wasps continue to
move for so long a time. There are here not any of the signs of life to
which I have been accustomed in my old studies of insect paralysis: the
antennary threads waving slowly to and fro, the palpi quivering, the
mandibles opening and closing for days, weeks and months on end. At
most, the tarsi tremble for a minute or two; that constitutes the whole
death-struggle. Complete immobility ensues. The inference drawn from
this sudden inertia is inevitable: the Wasp has stabbed the cervical
ganglia. Hence the immediate cessation of movement in all the organs of
the head; hence the real instead of the apparent death of the Bee. The
Philanthus is a butcher and not a paralyser.
This is one step gained. The murderess chooses the under part of
the chin as the point attacked in order to strike the principal
nerve-centres, the cephalic ganglia, and thus to do away with life
at one blow. When this vital seat is poisoned by the toxin, death
is instantaneous. Had the Philanthus' object been simply to effect
paralysis, the suppression of locomotor movements, she would have driven
her weapon into the flaw in the corselet, as the Cerceres do with the
Weevils, who are much more powerfully armoured than the Bee. But her
intention is to kill outright, as we shall see presently; she wants a
corpse, not a paralytic patient. This being so, we must agree that her
operating-method is supremely well-inspired: our human murderers could
achieve nothing more thorough or immediate.
We must also agree that her attitude when attacking, an attitude
very different from that of the paralysers, is infallible in its
death-dealing efficacy. Whether she deliver her thrust lying on the
ground or standing erect, she holds the Bee in front of her, breast to
breast, head to head. In this posture all that she need do is to curve
her abdomen in order to reach the gap in the neck and plunge the sting
with an upward slant into her captive's head. Suppose the two insects
to be gripping each other in the reverse attitude, imagine the dirk
to slant slightly in the opposite direction; the results would be
absolutely different and the sting, driven downwards, would pierce
the first thoracic ganglion and produce merely partial paralysis. What
skill, to sacrifice a wretched Bee! In what fencing-school was the
slayer taught her terrible upward blow under the chin?
If she learnt it, how is it that her victim, such a past mistress in
architecture, such an adept in socialistic polity, has so far learnt no
corresponding trick to serve in her own defence? She is as powerful
as her executioner; like the other, she carries a rapier, an even more
formidable one and more painful, at least to my fingers. For centuries
and centuries the Philanthus has been storing her away in her cellars;
and the poor innocent meekly submits, without being taught by the annual
extermination of her race how to deliver herself from the aggressor by a
well-aimed thrust. I despair of ever understanding how the assailant has
acquired her talent for inflicting sudden death, when the assailed,
who is better-armed and quite as strong, wields her dagger anyhow and
therefore ineffectively. If the one has learnt by prolonged practice
in attack, the other should also have learnt by prolonged practice in
defence, for attack and defence possess a like merit in the fight for
life. Among the theorists of the day, is there one clear-sighted enough
to solve the riddle for us?
If so, I will take the opportunity of putting to him a second problem
that puzzles me: the carelessness, nay, more, the stupidity of the Bee
in the presence of the Philanthus. You would be inclined to think that
the victim of persecution, learning gradually from the misfortunes
suffered by her family, would show distress at the ravisher's approach
and at least attempt to escape. In my cages I see nothing of the sort.
Once the first excitement due to incarceration under the bell-glass or
the wire-gauze cover has passed, the Bee seems hardly to trouble about
her formidable neighbour. I see one side by side with the Philanthus on
the same honeyed thistle-head: assassin and future victim are drinking
from the same flask. I see some one who comes heedlessly to enquire who
that stranger can be, crouching in wait on the table. When the spoiler
makes her rush, it is usually at a Bee who meets her half-way, and, so
to speak, flings herself into her clutches, either thoughtlessly or out
of curiosity. There is no wild terror, no sign of anxiety, no tendency
to make off. How comes it that the experience of the ages, that
experience which, we are told, teaches the animal so many things, has
not taught the Bee the first element of apiarian wisdom: a deep-seated
horror of the Philanthus? Can the poor wretch take comfort by relying on
her trusty dagger? But she yields to none in her ignorance of fencing;
she stabs without method, at random. However, let us watch her at the
supreme moment of the killing.
When the ravisher makes play with her sting, the Bee does the same with
hers and furiously. I see the needle now moving this way or that way
in space, now slipping, violently curved, along the murderess' convex
surface. These sword-thrusts have no serious results. The manner
in which the two combatants are at grips has this effect, that the
Philanthus' abdomen is inside and the Bee's outside. The latter's sting
therefore finds under its point only the dorsal surface of the foe,
a convex, slippery surface and so well armoured as to be almost
invulnerable. There is here no breach into which the weapon can slip
by accident; and so the operation is conducted with absolute surgical
safety, notwithstanding the indignant protests of the patient.
After the fatal stroke has been administered, the murderess remains for
a long time belly to belly with the dead, for reasons which we shall
shortly perceive. There may now be some danger for the Philanthus. The
attitude of attack and defence is abandoned; and the ventral surface,
more vulnerable than the other, is within reach of the sting. Now the
deceased still retains the reflex use of her weapon for a few minutes,
as I learnt to my cost. Having taken the Bee too early from the
bandit and handling her without suspecting any risk, I received a most
downright sting. Then how does the Philanthus, in her long contact with
the butchered Bee, manage to protect herself against that lancet, which
is bent upon avenging the murder? Is there any chance of a commutation
of the death-penalty? Can an accident ever happen in the Bee's favour?
Perhaps.
One incident strengthens my faith in this perhaps. I had placed four
Bees and as many Eristales under the bell-glass at the same time, with
the object of estimating the Philanthus' entomological knowledge in the
matter of the distinction of species. Reciprocal quarrels break out
in the mixed colony. Suddenly, in the midst of the fray, the killer is
killed. She tumbles over on her back, she waves her legs; she is dead.
Who struck the blow? It was certainly not the excitable but pacific
Drone-fly; it was one of the Bees, who struck home by accident during
the thick of the fight. Where and how? I cannot tell. The incident
occurs only once in my notes, but it throws a light upon the question.
The Bee is capable of withstanding her adversary; she can then and there
slay her would-be slayer with a thrust of the sting. That she does
not defend herself to better purpose, when she falls into her enemy's
clutches, is due to her ignorance of fencing and not to the weakness
of her weapon. And here again arises, more insistently than before, the
question which I asked above: how is it that the Philanthus has learnt
for offensive what the Bee has not learnt for defensive purposes? I see
but one answer to the difficulty: the one knows without having learnt;
the other does not know because she is incapable of learning.
Let us now consider the motives that induce the Philanthus to kill her
Bee instead of paralysing her. When the crime has been perpetrated,
she manipulates her dead victim without letting go of it for a
moment, holding its belly pressed against her own six legs. I see
her recklessly, very recklessly, rooting with her mandibles in the
articulation of the neck, sometimes also in the larger articulation of
the corselet, behind the first pair of legs, an articulation of whose
delicate membrane she is perfectly well aware, even though, when using
her sting, she did not take advantage of this point, which is the most
readily accessible of all. I see her rough-handling the Bee's belly,
squeezing it against her own abdomen, crushing it in the press. The
recklessness of the treatment is striking; it shows that there is no
need for keeping up precautions. The Bee is a corpse; and a little
hustling here and there will not deteriorate its quality, provided there
be no effusion of blood. In point of fact, however rough the handling, I
fail to discover the slightest wound.
These various manipulations, especially the squeezing of the neck, at
once bring about the desired results: the honey in the crop mounts
to the Bee's throat. I see the tiny drops spurt out, lapped up by the
glutton as soon as they appear. The bandit greedily, over and over
again, takes the dead insect's lolling, sugared tongue into her mouth;
then she once more digs into the neck and thorax, subjecting the
honey-bag to the renewed pressure of her abdomen. The syrup comes and is
instantly lapped up and lapped up again. In this way the contents of
the crop are exhausted in small mouthfuls, yielded one at a time. This
odious meal at the expense of a corpse's stomach is taken in a sybaritic
attitude; the Philanthus lies on her side with the Bee between her legs.
The atrocious banquet sometimes lasts for half an hour or longer. At
last the drained Bee is discarded, not without regret, it seems, for
from time to time I see the manipulation renewed. After taking a turn
round the top of the bell-jar, the robber of the dead returns to her
prey and squeezes it, licking its mouth until the last trace of honey
has disappeared.
This frenzied passion of the Philanthus for the Bee's syrup is declared
in yet another fashion. When the first victim has been sucked dry, I
slip under the glass a second victim, which is promptly stabbed under
the chin and then subjected to pressure to extract the honey. A third
follows and undergoes the same fate without satisfying the bandit. I
offer a fourth and a fifth. They are all accepted. My notes mention one
Philanthus who in front of my eyes sacrificed six Bees in succession and
squeezed out their crops in the regulation manner. The slaughter came to
an end not because the glutton was sated but because my functions as a
purveyor were becoming rather difficult: the dry month of August causes
the insects to avoid my harmas, which at this season is denuded of
flowers. Six crops emptied of their honey: what an orgy! And even then
the ravenous creature would very likely not have scorned a copious
additional course, had I possessed the means of supplying it!
There is no reason to regret this break in the service; the little that
I have said is more than enough to prove the singular characteristics of
the Bee-slayer. I am far from denying that the Philanthus has an honest
means of earning her livelihood; I find her working on the flowers as
assiduously as the other Wasps, peacefully drawing her honeyed
beakers. The males even, possessing no lancet, know no other manner of
refreshment. The mothers, without neglecting the table d'hote of the
flowers, support themselves by brigandage as well. We are told of the
Skua, that pirate of the seas, that he swoops down upon the fishing
birds, at the moment when they rise from the water with a capture. With
a blow of the beak delivered in the pit of the stomach he makes them
give up their prey, which is caught by the robber in mid-air. The
despoiled bird at least gets off with nothing worse than a contusion
at the base of the throat. The Philanthus, a less scrupulous pirate,
pounces on the Bee, stabs her to death and makes her disgorge in order
to feed upon her honey.
I say feed and I do not withdraw the word. To support my statement I
have better reasons than those set forth above. In the cages in which
various Hunting Wasps, whose stratagems of war I am engaged in studying,
are waiting till I have procured the desired prey--not always an easy
thing--I have planted a few flower-spikes, a thistle-head or two, on
which are placed drops of honey renewed at need. Here my captives come
to take their meals. With the Philanthus, the provision of honeyed
flowers, though favourably received, is not indispensable. I have only
to let a few live Bees into her cage from time to time. Half a dozen
a day is about the proper allowance. With no other food than the syrup
extracted from the slain, I keep my insects going for a fortnight or
three weeks.
It is as plain as a pikestaff: outside my cages, when the opportunity
offers, the Philanthus must also kill the Bee on her own account. The
Odynerus asks nothing from the Chrysomela but a mere condiment, the
aromatic juice of the rump; the other extracts from her victim an ample
supplement to her victuals, the crop full of honey. What a hecatomb
of Bees must not a colony of these freebooters make for their personal
consumption, not to mention the stored provisions! I recommend the
Philanthus to the signal vengeance of our Bee-masters.
Let us go no deeper into the first causes of the crime. Let us accept
things as we know them for the moment, with their apparent or real
atrocity. To feed herself, the Philanthus levies tribute on the Bee's
crop. Having made sure of this, let us consider the bandit's method
more closely. She does not paralyse her capture according to the rites
customary among the Hunting Wasps; she kills it. Why kill it? If the
eyes of our understanding be not closed, the need for sudden death is
clear as daylight. The Philanthus proposes to obtain the honeyed broth
without ripping up the Bee, a proceeding which would damage the game
when it is hunted on behalf of the larvae, without resorting to the
murderous extirpation of the crop. She must, by able handling, by
skilful pressure, make the Bee disgorge, she must milk her, in a manner
of speaking. Suppose the Bee stung behind the corselet and paralysed.
That deprives her of her power of locomotion, but not of her vitality.
The digestive organs in particular retain or very nearly retain their
normal energy, as is proved by the frequent excretions that take place
in the paralysed prey, so long as the intestine is not empty, as is
proved above all by the victims of the Languedocian Sphex (Cf. "The
Hunting Wasp": chapters 8 to 10.--Translator's Note.), those helpless
creatures which I used to keep alive for forty days on end with a soup
consisting of sugar and water. It is absurd to hope, without therapeutic
means, without a special emetic, to coax a sound stomach into emptying
its contents. The stomach of the Bee, who is jealous of her treasure,
would lend itself to the process even less readily than another. When
paralysed, the insect is inert; but there are always internal energies
and organic forces which will not yield to the manipulator's pressure.
The Philanthus will nibble at the throat and squeeze the sides in vain:
the honey will not rise to the mouth so long as a vestige of life keeps
the crop closed.
Things are different with a corpse. The tension is relaxed, the muscles
become slack, the resistance of the stomach ceases and the bag of honey
is emptied by the robber's vigorous pressure. You see, therefore, that
the Philanthus is expressly obliged to inflict a sudden death, which
will do away at once with the elasticity of the organs. Where is the
lightning stroke to be delivered? The slayer knows better than we do,
when she sticks the Bee under the chin. The cerebral ganglia are reached
through the little hole in the neck and death ensues immediately.
The relation of these acts of brigandage cannot satisfy my distressing
habit of following each reply obtained with a fresh question, until the
granite wall of the unknowable rises before me. If the Philanthus is
an expert in killing Bees and emptying crops swollen with honey, this
cannot be merely an alimentary resource, especially when, in common with
the others, she has the banqueting-hall of the flowers. I cannot accept
her atrocious talent as inspired merely by the craving for a feast
obtained at the expense of an empty stomach. Something certainly escapes
us: the why and wherefore of that crop drained dry. A creditable motive
may lie hidden behind the horrors which I have related. What is it?
Any one can understand the vagueness of the observer's mind when he
first asks himself this question. The reader is entitled to be treated
with consideration. I will spare him the recital of my suspicions, my
gropings and my failures and will come straight to the results of my
long investigation. Everything has its harmonious reason for existence.
I am too fully persuaded of this to believe that the Philanthus pursues
her habit of profaning corpses solely to satisfy her greed. What does
the emptied crop portend? May it not be that...? Why, yes.... After all,
who knows?... Let us try along these lines.
The mother's first care is the welfare of the family. So far, we have
seen the Philanthus hunting only for her stomach's sake; let us watch
her hunting as a mother. Nothing is easier than to distinguish the two
performances. When the Wasp wants a few good mouthfuls and nothing more,
she scornfully abandons the Bee after picking her crop. The Bee is
to her a worthless remnant, which will shrivel where it lies and be
dissected by the Ants. If, on the other hand, she wants to stow away
the Bee as a provision for her larvae, she clasps her in her two
intermediate legs and, walking on the other four, goes round and round
the edge of the bell-glass, seeking for an outlet through which to fly
off with her prey. When she recognizes the circular track as impossible,
she climbs up the sides, this time holding the Bee by the antennae with
her mandibles and clinging to the polished and perpendicular surface
with her six feet. She reaches the top of the glass, stays for a little
while in the hollow of the knob at the top, returns to the ground,
resumes her circling and her climbing and does not decide to relinquish
her Bee until she has stubbornly attempted every means of escape. This
persistence on her part to retain her hold on the cumbrous burden tells
us pretty plainly that the game would go straight to the cells if the
Philanthus had her liberty.
Well, these Bees intended for the larvae are stung under the chin like
the others; they are real corpses; they are manipulated, squeezed,
drained of their honey exactly as the others are. In all these respects,
there is no difference between the hunt conducted to provide food
for the larvae and the hunt conducted merely to gratify the mother's
appetite.
As the worries of captivity might well be the cause of a few anomalies
in the insect's actions, I felt that I ought to enquire how things
happen in the open. I lay in wait near some colonies of Philanthi,
for longer perhaps than the question deserved, as it had already been
settled by what had happened under glass. My tedious watches were
rewarded from time to time. Most of the huntresses returned home
immediately, with the Bee under their abdomen; some halted on the
brambles hard by; and here I saw them squeezing the dead Bee and making
her disgorge the honey, which was greedily lapped up. After these
preliminaries the corpse was stored. Every doubt is therefore removed:
the provisions of the larva are first carefully drained of their honey.
Since we are on the spot, let us prolong our stay and enquire into the
customs of the Philanthus in a state of liberty. Serving dead prey,
which goes bad in a few days, the Bee-huntress cannot adopt the method
of certain insects which paralyse a number of separate heads of game and
fill the cell with provisions, completing the ration before laying
the egg. She needs the method of the Bembex, whose larva receives
the necessary nourishment at intervals, as it grows larger. The facts
confirm this deduction. Just now I described as tedious my watches near
the colonies of the Philanthi. They were tedious in fact, even more so
perhaps than those which the Bembeces used to inflict upon me in the old
days. Outside the burrows of the Great Cerceris and other Weevil-lovers,
outside those of the Yellow-winged Sphex, the Cricket-slayer, there is
plenty of distraction, thanks to the bustling movement of the hamlet.
The mother has hardly come back home before she goes out again, soon
returning laden with a new prey and once more setting out upon the
chase. The going and coming is repeated at close intervals until the
warehouse is full.
The burrow of the Philanthus is far from showing any such animation,
even in a populous colony. In vain were my watches prolonged for whole
mornings or afternoons; it was but very rarely that the mother whom I
had seen go in with a Bee came out again for a second expedition. Two
captures at most by the same huntress was all that I was able to
see during my long vigils. Feeding from day to day involves this
deliberation. Once the family is supplied with a sufficient ration for
the moment, the mother suspends her hunting-trips until further need
arises and occupies herself with mining-work in her underground house.
Cells are dug; I see the rubbish gradually pushed up to the surface.
Beyond this there is not a sign of activity; it is as though the burrow
were deserted.
The inspection of the site is no easy matter. The shaft descends to
a depth of nearly three feet in a compact soil, either vertically or
horizontally. The spade and pick, wielded by stronger but less expert
hands than mine, are indispensable, for which reason the process of
excavation is far from satisfying me fully. At the end of this long
tunnel, which the straw which I use for sounding despairs of ever
reaching, the cells are at last encountered, oval cavities with a
horizontal major axis. Their number and general arrangement escape me.
Some of them already contain the cocoon, which is slender and
semitransparent, like those of the Cerceris, and, like them, suggests
the shape of certain homoeopathic phials, with oval bellies surmounted
by a tapering neck. The cocoon is fastened to the end of the cell by
the tip of this neck, which is darkened and hardened by the larva's
excrement; it has no other support. It looks like a short club fixed by
the end of the handle along the horizontal axis of the nest. Other cells
contain the larva in a more or less advanced stage. The grub is munching
the last morsel served to it, with the scraps of the victuals already
consumed lying around it. Others lastly show me a Bee, one only, still
untouched and bearing an egg laid on her breast. This is the first
partial ration; the others will come as and when the grub grows larger.
My anticipations are thus confirmed: following the example of the
Bembeces, the Fly-killers, the Philanthus, the Bee-killer, lays her egg
on the first piece warehoused and at intervals adds to her nurselings'
repast.
The problem of the dead game is solved. There remains this other
problem, one of incomparable interest: why are the Bees robbed of their
honey before being served to the larvae? I have said and I say again
that the killing and squeezing cannot be explained and excused simply by
reference to the Philanthus' love of gormandizing. Robbing the worker
of her booty is nothing out of the way: we see it daily; but cutting her
throat in order to empty her stomach is going beyond a joke. And, as
the Bees packed away in the cellar are squeezed dry just as much as the
others, the thought occurs to my mind that a rumpsteak with jam is not
to everybody's liking and that the game stuffed with honey might well be
a distasteful or even unwholesome dish for the Philanthus' larvae. What
will the grub do when, sated with blood and meat, it finds the Bee's
honey-bag under its mandibles and especially when, nibbling at random,
it rips open the crop and spoils its venison with syrup? Will it thrive
on the mixture? Will the little ogre pass without repugnance from the
gamy flavour of a carcase to the scent of flowers? A blunt statement or
denial would serve no purpose. We must see. Let us see.
I rear some young Philanthus-grubs, already waxing large; but, instead
of supplying them with the prey taken from the burrows, I give them game
of my own catching, game replete with nectar from the rosemaries. My
Bees, whom I kill by crushing their heads, are readily accepted; and
I at first see nothing that corresponds with my suspicions. Then my
nurselings languish, disdain their food, give a careless bite here and
there and end by perishing, from the first to the last, beside their
unfinished victuals. All my attempts miscarry: I do not once succeed in
rearing my larvae to the stage of spinning the cocoon. And yet I am no
novice in the functions of a foster-father. How many pupils have not
passed through my hands and reached maturity in my old sardine-boxes as
comfortably as in their natural burrows!
I will not draw rash conclusions from this check; I am conscientious
enough to ascribe it to another cause. It may be that the atmosphere
of my study and the dryness of the sand serving as a bed have had a
bad effect on my charges, whose tender skins are accustomed to the warm
moisture of the subsoil. Let us therefore try another expedient.
It is hardly feasible to decide positively by the methods which I have
been following whether the honey is or is not repugnant to the grubs of
the Philanthus. The first mouthfuls consist of meat; and then nothing
particular occurs: it is the natural diet. The honey is met with later,
when the morsel has been largely bitten into. If hesitation and lack of
appetite are displayed at this stage, they come too late in the day
to be conclusive: the larva's discomfort may be due to other, known or
unknown, causes. The thing to do would be to offer the grub honey from
the first, before artificial rearing has affected its appetite. It is
useless, of course, to make the attempt with pure honey: no carnivorous
creature would touch it, though it were starving. The jam-sandwich is
the only device favourable to my plans, a meagre jam-sandwich, that is
to say, the dead Bee lightly smeared or varnished with honey by means of
a camel's-hair pencil.
Under these conditions, the problem is solved with the first few
mouthfuls. The grub that has bitten into the honeyed prey draws back in
disgust, hesitates a long time and then, urged by hunger, begins again,
tries this side and that and ends by refusing to touch the dish. For a
few days it pines away on top of its almost intact provisions; then it
dies. All that are subjected to this regimen succumb. Do they merely
perish of inanition in the presence of an unaccustomed food, which
revolts their appetite, or are they poisoned by the small quantity of
honey absorbed with the early mouthfuls? I cannot tell. The fact remains
that, whether poisonous or repugnant, the Bee in the state of bread and
jam is death to them; and this result explains, more clearly than the
unfavourable circumstance of my former experiment, my failures with the
Bee that had not been made to disgorge.
This refusal to touch the unwholesome or distasteful honey is connected
with principles of nutrition which are too general to constitute a
gastronomic peculiarity of the Philanthus. The other carnivorous larvae,
at least in the order of the Hymenoptera, are bound to share it. Let us
try. We will go to work as before. I unearth the larvae when they have
attained a medium size, to avoid the weakness of infancy; I take away
the natural provisions, smear the carcases separately with honey and,
when this is done, restore its victuals to each of the grubs. I had to
make a choice: not every subject was equally suited to my experiments. I
must reject the larvae which are fed on one fat joint, such as those
of the Scolia. The grub in fact attacks its prey at a determined point,
dips its head and neck into the insect's body, rooting skilfully in the
entrails to keep the game fresh until the end of the meal, and does
not withdraw from the breach until the whole skin is emptied of its
contents.
To make it let go with the object of coating the inside of the venison
with honey had two drawbacks: I should be compromising the lingering
vitality which saves the insect that is being devoured from going bad
and, at the same time, I should be disturbing the delicate art of the
devouring insect, which, if removed from the lode which it was working,
would no longer be able to recover it or to distinguish between the
lawful and the unlawful morsels. The larva of the Scolia, consuming its
Cetonia-grub, has taught us all that we want to know on this subject in
my earlier volume. (Chapters 2 to 5 of the present volume contain the
whole of the matter referred to above.--Translator's Note.) The only
acceptable larvae are those supplied with a heap of small insects, which
are attacked without any special art, dismembered at random and eaten up
quickly. Among these I have tested such as chance threw in my way: those
of various Bembeces, all fed on Flies, those of the Palarus, whose bill
of fare consists of a very large assortment of Hymenoptera; those of the
Tarsal Tachytes, supplied with young Locusts; those of the Nest-building
Odynerus, furnished with Chrysomela-grubs; those of the Sand Cerceris,
endowed with a pinch of Weevils. A goodly variety, as you see, of
consumers and consumed. Well, to all of these the seasoning with honey
proved fatal. Whether poisoned or disgusted, they all died in a few
days.
A strange result indeed! Honey, the nectar of the flowers, the sole diet
of the Bee-tribe in both its forms and the sole resource of the Wasp
in her a adult form, is to the larvae of the latter an object
of insurmountable repugnance and probably a toxic dish. Even the
transformation of the nymphosis surprises me less than this inversion
of the appetite. What happens in the insect's stomach to make the adult
seek passionately what the youngster refused lest it should die? This is
not a question of organic debility unable to endure a too substantial,
too hard, too highly spiced dish. The grub that gnaws the Cetonia-larva,
that generous piece of butcher's meat; the glutton that crunches its
batch of tough Locusts; the one that battens on nitrobenzine-flavoured
game: they certainly own unfastidious gullets and accommodating
stomachs. And these robust eaters allow themselves to die of hunger
or digestive troubles because of a drop of syrup, the lightest food
imaginable, suited to the weakness of extreme youth and a feast for the
adult besides! What a gulf of obscurity in the stomach of a wretched
grub!
These gastronomical researches called for a counterexperiment. The
carnivorous larva is killed by honey. Conversely, is the mellivorous
larva killed by animal food? Reservations are needful here, as in the
previous tests. We should be courting a flat refusal if we offered
a pinch of Locusts to the larvae of the Anthophora or the Osmia, for
instance. (For both these Wild Bees cf. "Bramble-bees and Others":
passim.--Translator's Note.) The honey-fed insect would not bite
into it. There would be no use whatever in trying. We must find the
equivalent of the jam-sandwich aforesaid; in other words, we must give
the larva its natural fare with a mixture of animal food. The addition
made by my artifices shall be albumen, as found in the egg of the Hen,
albumen the isomer of fibrin, which is the essential factor in any form
of prey.
On the other hand, the Three-horned Osmia lends herself most admirably
to my plans, because of her dry honey, consisting for the greater part
of floury pollen. I therefore knead this honey with albumen, graduating
the dose until its weight largely exceeds that of the flour. In this way
I obtain pastes of different degrees of consistency, but all firm enough
to bear the larva without danger of immersion. With too fluid a
mixture there would be a risk of death by drowning. Lastly I install a
moderately-developed larva on each of my albuminous cakes.
The dish of my inventing does not incite dislike: far from it. The grubs
attack it without hesitation and consume it with every appearance of
the usual appetite. Things could not go better if the food had not been
altered by my culinary recipes. Everything goes down, including the
morsels in which I feared that I had overdone the addition of albumen.
And--an even more important point--the Osmia-larvae fed in this manner
attain their normal dimensions and spin their cocoons, from which adult
insects issue in the following year. Notwithstanding the albuminous
regimen, the cycle of the evolution is achieved without impediment.
What are we to conclude from all this? I feel greatly embarrassed. Omne
vivum ex ovo, the physiologists tell us. Every animal is carnivorous, in
its first beginnings: it is formed and nourished at the cost of its egg,
in which albumen predominates. The highest, the mammal, adheres to this
diet for a long time: it has its mother's milk, rich in casein, another
isomer of albumen. The gramnivorous nestling is first fed on grubs,
which are better adapted to the niceties of its stomach; many of the
minutest new-born creatures, being at once left to their own devices,
take to animal food. In this way the original method of nourishment is
continued for all alike: the method which allows flesh to be made from
flesh and blood from blood, with no chemical process beyond the simplest
modification. At maturity, when the stomach has acquired its full
strength, vegetable food is adopted, involving a more complicated
chemistry but easier to obtain. Milk is followed by fodder, worms by
seeds, the prey in the burrow by the nectar of the flowers.
This supplies a partial explanation of the twofold diet of the
Hymenoptera with carnivorous larvae: meat first, honey next. But then
the note of interrogation is shifted. It stood elsewhere; it now stands
here. Why is the Osmia, who as a larva fares so well on albumen, fed on
honey at the start? Why do the Bee-tribe receive a vegetable diet when
the other members of the order receive an animal diet?
If I were a believer in evolution, I should say yes, by the fact of its
germ, every animal is originally carnivorous. The insect in particular
starts with albuminoid materials. Many larvae adhere to the egg-food,
many adult insects do likewise. But the struggle to fill the belly,
which after all is the struggle for life, demands something better than
the precarious hazards of the chase. Man, at first a ravenous hunter
after game, brought the flock into existence and turned shepherd to
avoid a time of dearth. An even greater progress inspired him to scrape
the earth and to sow seed, which assures him of a living. The evolution
from scarcity to moderation and from moderation to plenty has led to the
resources of husbandry.
The animals forestalled us this path of progress. The ancestors of the
Philanthus, in the remote ages of the lacustrian tertiary formations,
lived by prey in both the larval and the adult forms: they hunted for
themselves as well as for the family. They did not confine themselves
to emptying the Bee's crop, as their descendants do to this day: they
devoured the deceased. From the beginning to the end they remained
flesh-eaters. Later, fortunate innovators, whose race supplanted the
laggards, discovered an inexhaustible nourishment, obtained without
dangerous conflicts or laborious search: the sugary secretions of the
flowers. The costly habit of living on prey, which does not favour large
populations, was maintained for the feeble larvae; but the vigorous
adult broke herself of it to lead an easier and more prosperous life.
Thus, gradually, was formed the Philanthus of our day; thus was acquired
the twofold diet of the various predatory insects our contemporaries.
The Bee has done better still: from the moment of leaving the egg she
delivered herself completely from food-stuffs the acquisition of which
depended on chance. She discovered honey, the grubs' food. Renouncing
the chase for ever and becoming an agriculturalist pure and simple,
the insect attains a degree of physical and moral prosperity which the
predatory species are far from sharing. Hence the flourishing colonies
of the Anthophorae, the Osmiae, the Eucerae (A genus of long-horned
Burrowing Bees.--Translator's Note.), the Halicti and other
honey-manufacturers, whereas the predatory insects work in isolation;
hence the societies in which the Bee displays her wonderful tendencies,
the supreme expression of instinct.
This is what I should say if I belonged to that school. It all forms a
chain of very logical deductions and proffers itself with a certain air
of likelihood which we should be glad to find in a host of evolutionist
arguments put forward as irrefutable. Well, I will make a present of my
deductive views, without regret, to whoever cares to have them: I don't
believe one word of them; and I confess my profound ignorance of the
origin of the twofold diet.
What I do understand more clearly, after all these investigations, is
the tactics of the Philanthus. When witnessing her ferocious feasting,
the real reason of which was unknown to me, I heaped the most
ill-sounding epithets upon her, calling her a murderess, a bandit, a
pirate, a robber of the dead. Ignorance is always evil-tongued; the
man who does not know indulges in rude assertions and mischievous
interpretations. Now that my eyes have been opened to the facts, I
hasten to apologize and to restore the Philanthus to her place in my
esteem. In draining the crops of her Bees the mother is performing the
most praiseworthy of all actions: she is protecting her family against
poison. If she happens to kill on her own account and to abandon the
corpse after making it disgorge, I dare not reckon this against her as a
crime. When the habit has been formed of emptying the Bee's crop with
a good motive, there is a great temptation to do it again with no other
excuse than hunger. Besides, who knows? Perhaps there is always at the
back of her hunting some thought of game which might be useful for the
larvae. Although not carried into effect, the intention excuses the
deed.
I therefore withdraw my epithets in order to admire the insect's
maternal logic and to hold it up to the admiration of others. The honey
would be pernicious to the health of the larvae. How does the mother
know that the syrup, a treat for her, is unwholesome for her young?
To this question our science offers no reply. The honey, I say, would
imperil the grubs' lives, The Bee must therefore first be made to
disgorge. The disgorging must be effected without lacerating the victim,
which the nurseling must receive in the fresh state; and the operation
is impracticable on a paralysed insect because of the resistance of
the stomach. The Bee must therefore be killed outright instead of being
paralysed, or the honey will not be voided. Instantaneous death can be
inflicted only by wounding the primordial centre of life. The sting must
therefore aim at the cervical ganglia, the seat of innervation on which
the rest of the organism depends. To reach them there is only one way,
through the little gap in the throat. It is here therefore that the
sting must be inserted; and it is here in fact that it is inserted, in
a spot hardly as large as the twenty-fifth of an inch square. Suppress
a single link of this compact chain, and the Bee-fed Philanthus becomes
impossible.
That honey is fatal to carnivorous larvae is a fact which teems with
consequences. Several Hunting Wasps feed their families upon Bees. These
include, to my knowledge, the Crowned Philanthus (P. coronatus, FAB.),
who lines her burrows with big Halicti; the Robber Philanthus (P.
raptor, LEP.), who chases all the smaller-sized Halicti, suited to her
own dimensions, indifferently; the Ornate Cerceris (C. ornata, FAB.),
another passionate lover of Halicti; and the Palarus (P. flavipes,
FAB.), who, with a curious eclecticism, stacks in her cells the greater
part of the Hymenopteron clan that does not exceed her powers. What do
these four huntresses and the others of similar habits do with their
victims whose crops are more or less swollen with honey? They must
follow the example of the Bee-eating Philanthus and make them disgorge,
lest their family perish of a honeyed diet; they must manipulate the
dead Bee, squeeze her and drain her dry. Everything goes to show it. I
leave it to the future to display these dazzling proofs of my doctrine
in their proper light.