THE BEE-EATING PHILANTHUS
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
eases 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.