Brillat-Savarin, when pronouncing his famous maxim, "Tell me what you
eat and I will tell you what you are," certainly never suspected the
signal confirmation which the entomological world would bestow upon his
saying. Our gastrosopher was speaking only of the culinary caprices of
man rendered fastidious by the sweets of life; but he might, in a more
serious department of thought, have given his formula a wider and more
general bearing and applied it to the dishes which vary so greatly
according to latitude, climate and customs; he might above all have
taken into his reckoning the harsh realities suffered by the common
people, when perhaps his ideal of moral worth would have been found in
a platter of chick-peas oftener than in a pot of pate de foie gras. No
matter: his aphorism, the mere whimsical sally of an epicure, becomes an
imperious truth if we forget the luxury of the table and look into what
is eaten by the little world which swarms around us.
To each its mess. The cabbage Pieris consumes the pungent leaves of the
Cruciferae as the food of her infancy; the Silkworm disdains any foliage
other than that of the mulberry-tree. The Spurge Hawk-moth requires the
caustic milk-sap of the tithymals: the Corn-weevil the grain of wheat;
the Pea-weevil, the seeds of the Leguminosae; the Balaninus (A genus
of Beetles including the Acorn-weevil, the Nut-weevil and
others.--Translator's Note.) the hazel-nut, the chestnut, the acorn;
the Brachycera (A division of Flies including the Gad-flies and
Robber-flies.--Translator's Note.) the clove of garlic. Each has its
diet, each its plant; and each plant has its customary guests. Their
relations are so precise that in many cases one might determine the
insect by the vegetable which supports it, or the vegetable by the
insect.
If you know the lily, you may name as a Crioceris the tiny scarlet
Scarabaeid that inhabits it and peoples its leaves with larvae
which keep themselves cool beneath an overcoat of ordure. (For the
Lily-beetle, or Crioceris merdigera, cf. "The Glow-worm and Other
Beetles," by J. Henri Fabre, translated by Alexander Teixeira de Mattos:
chapters 16 and 17.--Translator's Note.) If you know the Crioceris, you
may name as a lily the plant which she devastates. It will not perhaps
be the common or white lily, but some other representative of the same
family--Turk's cap lily, orange lily, scarlet Martagon, lancifoliate
lily, tiger-spotted lily, golden lily--hailing from the Alps or the
Pyrenees, or brought from China or Japan. Relying on the Crioceris, who
is an expert judge of exotic as well as of native Liliaceae, you may
name as a lily the plant with which you are unacquainted and trust
the word of this singular botanical master. Whether the flower be red,
yellow, ruddy-brown or sown with crimson spots, characteristics so
unlike the immaculate whiteness of the familiar flower, do not hesitate,
adopt the name dictated by the Beetle. Where man is liable to mistake
the insect is never mistaken.
This insect botany, a cause of such grievous tribulations, has always
impressed the worker in the fields, who for all that, is a very
indifferent observer. The man who was the first to see his cabbage-plot
devastated by caterpillars made the acquaintance of the Pieris. Science
completed the process, in its desire to serve a useful purpose or merely
to seek truth for truth's sake; and to-day the relations between the
insect and the plant form a collection of records as important from the
philosophical as from the practical, agricultural point of view. What
is much less familiar to us, because it touches us less nearly, is the
zoology of the insect, that is to say, the selection which it makes,
to feed its larva, of this or that animal species, to the exclusion
of others. The subject is so vast that a volume were not sufficient to
exhaust it; besides, data are lacking in the vast majority of cases.
It is reserved for a still very distant future to raise this point of
biology to the level already reached by the question of vegetable diet.
It will be enough if I contribute a few observations scattered through
my writings or my notes.
What does the Wasp addicted to a predatory life eat, of course in the
larval state? Now, to begin with, we see natural sections which adopt as
their prey different species of one and the same order, in one and
the same group. Thus the Ammophilae hunt exclusively the larvae of
the night-flying Moths. This taste is shared by the Eumenes, a very
different genus. (Cf. "The Mason-wasps" by J. Henri Fabre, translated
by Alexander Teixeira de Mattos: chapter 1.--Translator's Note.) The
Spheges and Tachytes are addicted to Orthoptera; the Cerceres, apart
from a few exceptions, are faithful to the Weevil; both the Philanthi
and the Palari capture only Hymenoptera; the Pompili specialize in
hunting the Spider; the Astata revels in the flavour of Bugs; the
Bembeces want Flies and nothing else; the Scoliae enjoy the monopoly of
the Lamellicorn-grubs; the Pelopaei favour the young Epeirae (Or
Garden Spiders. Cf. "The Life of the Spider": chapters 9 to 14 and
appendix.--Translator's Note.), the Stizi vary in opinion: of the two in
my neighbourhood, one, S. ruficornis, fills her larder with Mantes and
the other, S. tridentatus, fills it with Cicadellae (Cf. "The Life
of the Grasshopper": chapter 20.--Translator's Note.); lastly, the
Crabronidae (Any Flies akin to the House-fly.--Translator's Note.). levy
tribute upon the rabble of the Muscidae. (Hornets.--Translator's Note.)
Already you see what a magnificent classification of these game-hunters
might be made with a faithfully listed bill of fare. Natural groups
stand out, characterized merely by the identity of their victuals. I
trust that the methodical science of the future will take account of
these gastronomic laws, to the great relief of the entomological novice,
who is too often hampered by the snares of the mouth-parts, the antennae
and the nervures of the wings. I call for a classification in which the
insect's aptitudes, its diet, its industry and its habits shall take
precedence of the shape of a joint in its antennae. It will come; but
when?
If from generalities we descend to details, we shall see that the very
species may, in many instances, be determined from the nature of its
victuals. The number of burrows of Philanthus apivorus which I have
inspected since I have been rummaging the hot roadside embankments, to
enquire into their population, would seem hyperbolical were I able to
state the figures. (For the Bee-eating Philanthus cf. Chapter 10 of the
present volume.--Translator's Note.) They must amount, it seems to me,
to thousands. Well, in this multitude of food-stores, whether recent or
ancient, uncovered for a purpose or encountered by chance, I have not
once, not as often as once, discovered other remains than those of the
Hive-bee: the imperishable wings, still connected in pairs, the cranium
and thorax enveloped in a violet shroud, the winding-sheet which time
throws over these relics. To-day as when I was a beginner, ever so long
ago; in the north as in the south of the country which I explored;
in mountainous regions as on the plains, the Philanthus follows an
unvarying diet: she must have the Hive-bee, always the Bee and never any
other, however closely various other kinds of game resemble the Bee in
quality. If, therefore, when exploring sunny banks, you find beneath the
soil a small parcel of mutilated Bees, that will be enough to point to
the existence of a local colony of Philanthus apivorus. She alone
knows the recipe for making potted Bee-meat. The Crioceris was but now
teaching us all about the lily family; and here the mildewed body of the
Bee tells us of the Philanthus and her lair.
Similarly the female Ephippiger helps us to identify the Languedocian
Sphex: her relics, the cymbals and the long sabre, are the unmistakable
sign of the cocoon to which they adhere. The black Cricket, with his
red-braided thighs, is the infallible label of the Yellow-winged
Sphex; the larva of Oryctes nasicornis tells us of the Garden Scolia
as certainly as the best description; the Cetonia-grub proclaims the
Two-banded Scolia and the larva of the Anoxia announces the Interrupted
Scolia.
After these exclusive ones, who disdain to vary their meals, let us
mention the eclectics, who, in a group which is generally well-defined,
are able to select among different kinds of game appropriate to their
bulk. The Great Cerceris (Cerceris tuberculata. Cf. "The Hunting
Wasps": chapters 2 and 3.--Translator's Note.) favours above all Cleonus
ophthalmicus, one of the largest of our Weevils; but at need she accepts
the other Cleoni, as well as the kindred genera, provided that the
capture be of an imposing size. Cerceris arenaria (Cf. idem: chapter
1.--Translator's Note.) extends her hunting-grounds farther afield:
any Weevil of average dimensions is to her a welcome capture. The
Buprestis-hunting Cerceris adopts all the Buprestes indiscriminately,
so long as they are not beyond her strength. The Crowned Philanthus (P.
coronatus, FAB.) fills her underground warehouses with Halicti chosen
among the biggest. (Cf. "Bramble-bees and Others" by J. Henri
Fabre, translated by Alexander Teixeira de Mattos: chapters 12 to
14.--Translator's Note.) Much smaller than her kinswoman, Philanthus
raptor, LEP., stores away Halicti chosen among the less large species.
Any adult Acridian approaching an inch in length suits the White-banded
Sphex. The various tidae of the neighbourhood are admitted to the larder
of Stizus ruficornis and of the Mantis-hunting Tachytes on the sole
condition of being young and tender. The largest of our Bembeces (B.
rostrata, FAB., and B. bidentata, VAN DER LIND (For the Rostrate
Bembex and the Two-pronged Bembex, cf. "The Hunting Wasps": chapter
14.--Translator's Note.)) are eager consumers of Gad-flies. With these
chief dishes they associate relishes levied indifferently from the rest
of the Fly clan. The Sandy Ammophila (A. sabulosa, VAN DER LIND (Cf.
idem: chapter 13.--Translator's Note.)) and the Hairy Ammophila
(A. hirsuta, KIRB.) cram into each burrow a single but corpulent
caterpillar, always of the Moth tribe and varying greatly in coloration,
which denotes distinct species. The Silky Ammophila (A. holosericea,
VAN DER LIND. (Cf. idem: chapter 14.--Translator's Note.)) has a better
assorted diet. She requires for each banqueter three or four items,
which include the Measuring-worms, or Loopers, and the caterpillars of
ordinary Moths, all of which are equally appreciated. The Brown-winged
Solenius (S. fascipennis, LEP.), who elects to dwell in the soft dead
wood of old willow-trees, has a marked preference for Virgil's Bee,
Eristalis tenax (Actually the Common Drone-fly and somewhat resembling
a Bee in appearance. Cf. "The Hunting Wasps": chapter 14.--Translator's
Note.), willingly adding, sometimes as a side-dish, sometimes as the
principal game, Helophilus pendulus, whose costume is very different. On
the faith of indistinguishable remains, we must no doubt enter a number
of other Flies in her game-book. The Golden-mouthed Hornet (Crabro
chrysostomus, LEP.) another burrower in old willow-trees, prefers the
Syrphi, without distinction of species. (The Syrphi, like the Eristales,
resemble Bees through having the abdomen transversely banded with
yellow.--Translator's Note.) The Wandering Solenius (S. vagus, LEP. (For
this Fly-hunting insect cf. "Bramble-bees and Others": chapters 1 and
3.--Translator's Note.)), an inmate of the dry bramble-stems and of the
dwarf-elder, lays under contribution for her larder the genera Syritta,
Sphaerophoria, Sarcophaga, Syrphus, Melanophora, Paragus and apparently
many others. The species which recurs most frequently in my notes is
Syritta pipiens.
Without pursuing this tedious list any farther, we plainly perceive the
general result. Each huntress has her characteristic tastes, so much
so that, when we know the bill of fare, we can tell the genus and very
often the species of the guest, thus proving the proud truth of the
maxim, "Tell me what you eat and I will tell you what you are."
There are some which always need the same prey. The offspring of the
Languedocian Sphex religiously consume the Ephippiger, that family dish
so dear to their ancestors and no less dear to their descendants; no
innovation in the ancient usages can tempt them. Others are better
suited by variety, for reasons connected with flavour or with facility
of supply; but then the selection of the game is kept within fixed
limits. A natural group, a genus, a family, more rarely almost a whole
order: this is the hunting-ground beyond which poaching is strictly
forbidden. The law is absolute; and one and all scrupulously refrain
from transgressing it.
In the place of the Praying Mantis, offer the Mantis-hunting Tachytes an
equivalent in the shape of a Locust. She will scorn the morsel, though
it would seem to be of excellent flavour, seeing that Panzer's Tachytes
prefers it to any other form of game. Offer her a young Empusa, who
differs so widely from the Mantis in shape and colour: she will accept
without hesitation and operate before your eyes. Despite its fantastic
appearance, the Devilkin is instantly recognized by the Tachytes as a
Mantid and therefore as game falling within her scope.
In exchange for her Cleonus, give to the Great Cerceris a Buprestis, the
delight of one of her near kinsfolk. She will have nothing to say to the
sumptuous dish. Accept that! She, a Weevil-eater! Never in this world!
Present her with a Cleonus of a different species, or any other large
Weevil, of a sort which she has most probably never seen before, since
it does not figure on the inventory of the provisions in her burrows.
This time there is no show of disdain: the victim is seized and stabbed
in the regulation manner and forthwith stored away.
Try to persuade the Hairy Ammophila that Spiders have a nutty flavour,
as Lalande asserts; and you will see how coldly your hints are received.
(Joseph Jerome Le Francois de Lalande (1732-1807), the astronomer.
Even after he had achieved his reputation, he sought means, outside the
domain of science, to make himself talked about and found these in
the display partly of odd tastes, such as that for eating Spiders and
caterpillars, and partly of atheistical opinions.--Translator's Note.)
Try merely to convince her that the caterpillar of a Butterfly is as
good to eat as the caterpillar of a Moth. You will not succeed. But, if
you substitute for her underground larva, which I suppose to be grey,
another underground larva striped with black, yellow, rusty-red or
any other tint, this change of coloration will not prevent her from
recognizing, in the substituted dish, a victim to her liking, an
equivalent of her Grey Worm.
So with the rest, so far as I have been able to experiment with them.
Each obstinately refuses what is alien to her hunting-preserves,
each accepts whatever belongs to them, always provided that the game
substituted is much the same in size and development as that whereof
the owner has been deprived. Thus the Tarsal Tachytes, an appreciative
epicure of tender flesh, would not consent to replace her pinch of young
Acridian-grubs with the one big Locust that forms the food of Panzer's
Tachytes; and the latter, in her turn, would never exchange her adult
Acridian for the other's menu of small fry. The genus and the species
are the same, but the age differs; and this is enough to decide the
question of acceptance or refusal.
When its depredations cover a somewhat extensive group, how does
the insect manage to recognize the genera, the species composing her
allotted portion and to distinguish them from the rest with an assured
vision which the inventory of her burrows proves never to be at
fault? Is it the general appearance that guides her? No, for in some
Bembex-burrows we shall find Sphaerophoriae, those slender, thong-like
creatures, and Bombylii, looking like velvet pincushions; no again,
for in the pits of the Silky Ammophila we shall see, side by side, the
caterpillar of the ordinary shape and the Measuring-worm, a living pair
of compasses which progresses by alternately opening out and closing;
no, once more, for in the storerooms of Stizus ruficornis and the
Mantis-hunting Tachytes we see stacked beside the Mantis the Empusa, her
unrecognizable caricature.
Is it the colouring? Not at all. There is no lack of instances. What
a variety of hues and metallic reflections, distributed in a host of
different fashions, appear in the Buprestes that are hunted by the
Cerceris celebrated by Leon Dufour. (Jean Marie Leon Dufour (1780-1865)
was an army surgeon who served with distinction in several campaigns
and subsequently practised as a doctor in the Landes. He attained great
eminence as a naturalist. Cf. "The Hunting Wasps": chapter 1; also
"The Life of the Spider": chapter 1.--Translator's Note.) A painter's
palette, containing crushed gold, bronze, ruby and amethyst, would find
it difficult to rival these sumptuous colours. Nevertheless the Cerceris
makes no mistake: all this nation of insects, so indifferently attired,
represents to her, as to the entomologist, the nation of the Buprestes.
The inventory of the Hornet's larder will include Diptera clad in grey
or russet frieze; others are girdled with yellow, flecked with white,
adorned with crimson lines; others are steel-blue, ebony black, or
coppery green; and underneath this variety of dissimilar costumes we
find the invariable Fly.
Let us take a concrete example. Ferrero's Cerceris (C. Ferreri, VAN DER
LIND) consumes Weevils. Her burrows are usually lined with Phynotomi
and Sitones both an indeterminate grey, and Otiorhynchi, black or
tan-coloured. Now I have sometimes happened to unearth from her cells
a collection of veritable jewels which, thanks to their bright metallic
lustre, made a most striking contrast with the sombre Otiorhynchus.
These were the Rhynchites (R. betuleti), who roll the vine-leaves into
cigars. Equally magnificent, some of them were azure blue, others copper
gilt, for the cigar-roller has a twofold colouring. How did the Cerceris
manage to recognize in these jewels the Weevil, the near relative of
the vulgar Phynotomus? Any such encounters probably found her lacking
in expert knowledge; her race cannot have handed down to her other
than very indeterminate propensities, for she does not appear to make
frequent use of the Rhynchites, as is proved by my infrequent discovery
of them amid the mass of my numerous excavations. For the first time,
perhaps, passing through a vineyard, she saw the rich Beetle gleaming on
a leaf; it was not for her a dish in current consumption, consecrated by
the ancient usages of the family. It was something novel, exceptional,
extraordinary. Well, this extraordinary creature is recognized with
certainty as a Weevil and stored away as such. The glittering cuirass
of the Rhynchites goes to take its place beside the grey cloak of the
Phynotomus. No, it is not the colour that guides the choice.
Neither is it the shape. Cerceris arenaria hunts any medium-sized
Weevil. I should be putting the reader's patience to too great a test if
I attempted to give in this place a complete inventory of the specimens
identified in her larder. I will mention only two, which my latest
searches around my village have revealed. The Wasp goes hunting on
the holm-oaks of the neighbouring hills the Pubescent Brachyderes (B.
pubescens) and the Acorn-weevil (Balaninus glandium). What have
these two Beetles in common as regards shape? I mean by shape not
the structural details which the classifier examines through his
magnifying-glass, not the delicate features which a Latreille would
quote when drawing up a technical description, but the general picture,
the general outline that impresses itself upon the vision even of an
untrained eye and makes the man who knows nothing of science and above
all the child, a most perspicacious observer, connect certain animals
together.
In this respect, what have the Brachyderes and the Balaninus in common
in the eyes of the townsman, the peasant, the child or the Cerceris?
Absolutely nothing. The first has an almost cylindrical figure; the
second, squat, short and thickset, is conical in front and elliptical,
or rather shaped like the ace of hearts, behind. The first is black,
strewn with cloudy, mouse-grey spots; the second is yellow ochre. The
head of the first ends in a sort of snout; the head of the second tapers
into a curved beak, slender as a horse-hair and as long as the rest of
the body. The Brachyderes has a massive proboscis, cut off short; the
Balaninus seems to be smoking an insanely long cigarette-holder.
Who would think of connecting two creatures so unlike, of calling them
by the same name? Outside the professional classifiers, no one would
dare to. The Cerceris, more perspicacious, knows each of them for a
Weevil, a quarry with a concentrated nervous system, lending itself to
the surgical feat of her single stroke of the lancet. After obtaining an
abundant booty at the cost of the blunt-mouthed insect, with which
she sometimes stuffs her cellars to the exclusion of any other fare,
according to the hazards of the chase, she now suddenly sees before her
the creature with the extravagant proboscis. Accustomed to the first,
will she fail to know the second? By no means: at the first glance she
recognizes it as her own; and the cell already furnished with a few
Brachyderes receives its complement of Balanini. If these two species
are to seek, if the burrows are far from the holm-oaks, the Cerceris
will attack Weevils displaying the greatest variety of genus, species,
form and coloration, levying tribute indifferently on Sitones,
Cneorhini, Geonemi, Otiorhynchi, Strophosomi and many others.
In vain do I rack my brains merely to guess at the signs upon which
the huntress relies as a guide, without going outside one and the
same group, in the midst of such a variety of game; above all by what
characteristics she recognizes as a Weevil the strange Acorn Balaninus,
the only one among her victims that wears a long pipe-stem. I leave to
evolutionism, atavism and other transcendental "isms" the honour and
also the risk of explaining what I humbly recognize as being too far
beyond my grasp. Because the son of the bird-catcher who imitates
the call of his victims has been fed on roast Robins, Linnets and
Chaffinches, shall we hastily conclude that this education through the
stomach will enable him later, without other initiation than that of
the spit, to know his way about the ornithological groups and to avoid
confusing them when his turn comes to set his limed twigs? Will the
digesting of a ragout of little birds, however often repeated by him
or his ascendants, suffice to make him a finished bird-catcher?
The Cerceris has eaten Weevil; her ancestors have all eaten Weevil,
religiously. If you see in this the reason that makes the Wasp a
Weevil-expert endowed with a perspicacity unrivalled save by that of a
professional entomologist, why should you refuse to admit that the same
consequences would follow in the bird-catcher's family?
I hasten to abandon these insoluble problems in order to attack the
question of provisions from another point of view. Every Hunting Wasp is
confined to a certain genus of game, which is usually strictly limited.
She pursues her appointed quarry and regards anything outside it with
suspicion and distaste. The tricks of the experimenter, who drags her
prey from under her and flings her another in exchange, the emotions of
the possessor deprived of her property and immediately recovering it,
but under another form, are powerless to put her on the wrong scent.
Obstinately she refuses whatever is alien to her portion; instantly
she accepts whatever forms part of it. Whence arises this insuperable
repugnance for provisions to which the family is unaccustomed? Here we
may appeal to experiment. Let us do so: its dictum is the only one that
can be trusted.
The first idea that presents itself and the only one, I think, that can
present itself is that the larva, the carnivorous nurseling, has its
preferences, or we had better say its exclusive tastes. This kind of
game suits it; that does not; and the mother provides it with food in
conformity with its appetites, which are unchangeable in each species.
Here the family dish is the Gad-fly; elsewhere it is the Weevil;
elsewhere again it is the Cricket, the Locust and the Praying Mantis.
Good in themselves, in a general way, these several victuals may be
noxious to a consumer who is not used to them. The larva which dotes on
Locust may find caterpillar a detestable fare; and that which revels
in caterpillar may hold Locust in horror. It would be hard for us to
discover in what manner Cricket-flesh and Ephippiger-flesh differ
as juicy, nourishing foodstuffs; but it does not follow that the two
Sphex-wasps addicted to this diet have not very decided opinions on the
matter, or that each of them is not filled with the highest esteem for
its traditional dish and a profound dislike for the other. There is no
discussing tastes.
Moreover, the question of health may well be involved. There is nothing
to tell us that the Spider, that treat for the Pompilus, is not poison,
or at least unwholesome food, to the Bembex, the lover of Gad-flies;
that the Ammophila's succulent caterpillar is not repugnant to the
stomach of the Sphex fed upon the dry Acridian. The mother's esteem for
one kind of game and her distrust of another would in that case be due
to the likes and dislikes of her larvae; the victualler would regulate
the bill of fare by the gastronomic demands of the victualled.
This exclusiveness of the carnivorous larva seems all the more probable
inasmuch as the larva reared on vegetable food refuses in any way
to lend itself to a change of diet. However pressed by hunger, the
caterpillar of the Spurge Hawk-moth, which browses on the tithymals,
will allow itself to starve in front of a cabbage leaf which makes a
peerless meal for the Pieris. Its stomach, burned by pungent spices,
will find the Crucifera insipid and uneatable, though its piquancy is
enhanced by essence of sulphur. The Pieris, on its part, takes good
care not to touch the tithymals: they would endanger its life. The
caterpillar of the Death's-head Hawk-moth requires the solanaceous
narcotics, principally the potato, and will have nothing else. All that
is not seasoned with solanin it abhors. And it is not only larvae whose
food is strongly spiced with alkaloids and other poisonous substances
that refuse any innovation in their food; the others, even those whose
diet is least juicy, are invincibly uncompromising. Each has its plant
or its group of plants, beyond which nothing is acceptable.
I remember a late frost which had nipped the buds of the mulberry-trees
during the night, just when the first leaves were out. Next day there
was great excitement among my neighbours: the Silk-worms had hatched
and the food had suddenly failed. The farmers had to wait for the sun
to repair the disaster; but how were they to keep the famishing new-born
grubs alive for a few days? They knew me for an expert in plants; by
collecting them as I walked through the fields I had earned the name
of a medical herbalist. With poppy-flowers I prepared an elixir which
cleared the sight; with borage I obtained a syrup which was a sovran
remedy for whooping-cough; I distilled camomile; I extracted the
essential oil from the wintergreen. In short, botany had won for me the
reputation of a quack doctor. After all, that was something.
The housewives came in search of me from every point of the compass and
with tears in their eyes explained the situation. What could they give
their Silk-worms while waiting for the mulberry to sprout afresh? It was
a serious matter, well worthy of commiseration. One was counting on her
batch to buy a length of cloth for her daughter, who was on the point of
getting married; another told me of her plans for a Pig to be fattened
against the coming winter; all deplored the handful of crown-pieces
which, hoarded in the hiding-place in the cupboard, would have afforded
help in difficult times. And, full of their troubles, they unfolded,
before my eyes, a scrap of flannel on which the vermin were swarming:
"Regardas, moussu! Venoun d'espeli; et ren per lour douna! Ah, pecaire!"
"Look, sir! The frost has come and we've nothing to give them! Oh, what
a misfortune!"
Poor people! What a harsh trade is yours: respectable above all others,
but of all the most uncertain! You work yourselves to death; and, when
you have almost reached your goal, a few hours of a cold night, which
comes upon you suddenly, destroys your harvest. To help these afflicted
ones seemed to me a very difficult thing. I tried, however, taking
botany as my guide; it suggested to me, as substitutes for the mulberry,
the members of closely-related families: the elm, the nettle-tree, the
nettle, the pellitory. Their nascent leaves, chopped small, were offered
to the Silk-worms. Other and far less logical attempts were made, in
accordance with the inspiration of the individuals. Nothing came of
them. To the last specimen, the new-born Silk-worms died of hunger. My
renown as a quack must have suffered somewhat from this check. Was it
really my fault? No, it was the fault of the Silk-worm, which remained
faithful to its mulberry leaf.
It was therefore in nearly the certainty of non-fulfilment that I made
my first attempts at rearing carnivorous larvae with a quarry which did
not conform with the customary regimen. For conscience' sake, more or
less perfunctorily, I endeavoured to achieve something that seemed to
me bound to end in pitiful failure. Only the Bembex-wasps, which are
plentiful in the sand of the neighbouring hills, might still afford me,
without too prolonged a search, a few subjects on which to experiment.
The Tarsal Bembex furnished me with what I wanted: larvae young enough
to have still before them a long period of feeding and yet sufficiently
developed to endure the trials of a removal.
These larva are exhumed with all the consideration which their delicate
skin demands; a number of head of game are likewise unearthed intact,
having been recently brought by the mother. They consist of various
Diptera, including some Anthrax-flies. (Cf. "The Life of the Fly":
chapters 2 and 4.--Translator's Note.) An old sardine-box, containing a
layer of sifted sand and divided into compartments by paper partitions,
receives my charges, who are isolated one from another. These Fly-eaters
I propose to turn into Grasshopper-eaters; for their Bembex-diet I
intend to substitute the diet of a Sphex or a Tachytes. To save myself
tedious errands devoted to provisioning the refectory, I accept what
good fortune offers me at the very threshold of my door. A green
Locustid, with a short sabre bent into a reaping-hook, Phaneroptera
falcata, is ravaging the corollae of my petunias. Now is the time to
indemnify myself for the damage which she has caused me. I pick her
young, half to three-quarters of an inch in length; and I deprive her of
movement, without more ado, by crushing her head. In this condition she
is served up to the Bembex-larvae in place of their Flies.
If the reader has shared my convictions of failure, convictions based
on very logical motives, he will now share my profound surprise. The
impossible becomes possible, the senseless becomes reasonable and
the expected becomes the opposite of the real. The dish served on the
Bembeces' table for the first time since Bembeces came into the world
is accepted without any repugnance and consumed with every mark of
satisfaction. I will here set down the detailed diary of one of my
guests; that of the others would only be a repetition, save for a few
variations.
2 AUGUST, 1883.--The larva of the Bembex, as I extract it from its
burrow, is about half-developed. Around it I find only some
scanty relics of its meals, consisting chiefly of Anthrax-wings,
half-diaphanous and half-clouded. The mother would appear to have
completed the victualling by fresh contributions, added day by day. I
give the nurseling, which is an Anthrax-eater, a young Phaneroptera.
The Locustid is attacked without hesitation. This profound change in
the character of its victuals does not seem in the least to disturb the
larva, which bites straight into the rich morsel with its mandibles and
does not let go until it has exhausted it. Towards evening the drained
carcase is replaced by another, quite fresh, of the same species but
bulkier, measuring over three-quarters of an inch.
3 AUGUST.--Next day I find the Phaneroptera devoured. Nothing remains
but the dry integuments, which are not dismembered. The entire contents
have disappeared; the game has been emptied through a large opening made
in the belly. A regular Grasshopper-eater could not have operated more
skilfully. I replace the worthless carcase by two small Locustidae. At
first the larva does not touch them, being amply sated with the copious
meal of the day before. In the afternoon, however, one of the items is
resolutely attacked.
4 AUGUST.--I renew the victuals, although those of the day before are
not finished. For the rest, I do the same daily, so that my charge may
constantly have fresh food at hand. High game might upset its stomach.
My Locustidae are not victims at the same time living and inert,
operated upon according to the delicate method of the insects that
paralyse their prey; they are corpses, procured by a brutal crushing
of the head. With the temperature now prevailing, flesh soon becomes
tainted; and this compels me frequently to renew the provisions in my
sardine-box refectory. Two specimens are served up. One is attacked soon
afterwards; and the larva clings to it assiduously.
5 AUGUST.--The ravenous appetite of the start is becoming assuaged.
My supplies may well be too generous; and it might be prudent to try a
little dieting after this Gargantuan good cheer. The mother certainly is
more parsimonious. If all the family were to eat at the same rate as
my guest, she would never be able to keep pace with their demands.
Therefore, for reasons of health, this is a day of fasting and vigil.
6 AUGUST.--Supplies are renewed with two Phaneropterae. One is consumed
entirely; the other is bitten into.
7 August.--To-day's ration is tasted and then abandoned. The larva seems
uneasy. With its pointed mouth it explores the walls of its chamber.
This sign denotes the approach of the time for making the cocoon.
8 AUGUST.--During the night the larva has spun its silken eel-trap. It
is now encrusting it with grains of sand. Then follow, in due time, the
normal phases of the metamorphosis. Fed on Locustidae, a diet unknown to
its race, the larva passes through its several stages without any more
difficulty than its brothers and sisters fed on Flies.
I obtained the same success in offering young Mantes for food. One
of the larvae thus served would even incline me to believe that
it preferred the new dish to the traditional diet of its race. Two
Eristales, or Drone-flies, and a Praying Mantis an inch long composed
its daily allowance. The Drone-flies are disdained from the first
mouthful; and the Mantis, already tasted and apparently found excellent,
causes the Fly to be completely forgotten. Is this an epicure's
preference, due to the greater juiciness of the flesh? I am not in a
position to say. At all events, the Bembex is not so infatuated with Fly
as to refuse to abandon it for other game.
The failure which I foresaw has proved a magnificent success. It is
fairly convincing, is it not? Without the evidence of experiment, what
can we rely upon? Beneath the ruins of so many theories which appeared
to be most solidly erected I should hesitate to admit that two and two
make four if the facts were not before me. My argument had the most
tempting probability on its side, but it had not the truth. As it is
always possible to find reasons after the event in support of an opinion
which one would not at first admit, I should now argue as follows:
The plant is the great factory in which are elaborated, with mineral
materials, the organic principles which are the materials of life.
Certain products are common to the whole vegetable series, but others,
far less numerous, are prepared in special laboratories. Each genus,
each species has its trade-mark. Here essential oils are manufactured;
here alkaloids; here starches, fatty substances, resins, sugars, acids.
Hence result special energies, which do not suit every herbivorous
animal. It assuredly requires a stomach made expressly for the purpose
to digest aconite, colchicum, hemlock or henbane; those who have not
such a stomach could never endure a diet of that sort. Besides, the
Mithridates fed on poison resist only a single toxin. (Mithridates VI.
King of Pontus (d. B.C. 63) is said to have secured immunity from poison
by taking increased doses of it.--Translator's Note.) The caterpillar of
the Death's-head Hawk-moth, which delights in the solanin of the potato,
would be killed by the acrid principle of the tithymals that form the
food of the Spurge-caterpillar. The herbivorous larvae are therefore
perforce exclusive in their tastes, because different genera of
vegetables possess very different properties.
With this variety in the products of the plant, the animal, a consumer
far more than a producer, contrasts the uniformity in its own products.
The albumen in the egg of the Ostrich or the Chaffinch, the casein in
the milk of the Cow or the Ass, the muscular flesh of the Wolf or the
Sheep, the Screech-owl or the Field-mouse, the Frog or the Earth-worm:
these remain albumen, casein or fibrin, edible if not eaten. Here are
no excruciating condiments, no special acridities, no alkaloids fatal
to any stomach other than that of the appointed consumer; so that animal
food is not confined to one and the same eater. What does not man eat,
from that delicacy of the arctic regions, soup made of Seal's blood and
a scrap of Whale-blubber wrapped in a willow-leaf for a vegetable, to
the Chinaman's fried Silk-worm or the Arab's dried Locust? What would
he not eat, if he had not to overcome the repugnance dictated by habit
rather than by actual necessity? The prey being uniform in its nutritive
principles, the carnivorous larva ought to accommodate itself to any
sort of game, above all if the new dish be not too great a departure
from consecrated usage. Thus should I argue, with no less probability on
my side, had I to begin all over again. But, as all our arguments have
not the value of a single fact, I should be forced in the end to resort
to experiment.
I did so the next year, on a larger scale and with a greater variety of
subjects. I shrink from a continuous narrative of my experiments and
of my personal education in this new art, where the failure of one
day taught me the way to succeed on the morrow. It would be long and
tedious. Enough if I briefly state my results and the conditions which
must be fulfilled in order to run the delicate refectory as it should be
run.
And, first, we must not dream of detaching the egg from its natural prey
to lay it on another. The egg adheres pretty firmly, by its cephalic
pole, to the quarry. To remove it from its place would inevitably
jeopardize its future. I therefore let the larva hatch and acquire
sufficient strength to bear the removal without peril. For that matter,
my excavations most often provide me with my subjects in the form of
larvae. I adopt for rearing-purposes the larvae that are a quarter to a
half developed. The others are too young and risky to handle, or too old
and limited to a short period of artificial feeding.
Secondly, I avoid bulky heads of game, a single one of which would
suffice for the whole growing-stage. I have already said and I here
repeat how nice a matter it is to consume a victim which has to keep
fresh for a couple of weeks and not to finish dying until it is almost
entirely devoured. Death here leaves no corpse; when life is extinct,
the body has disappeared, leaving only a shred of skin. Larvae with only
one large prey have a special art of eating, a dangerous art, in which a
clumsy bite would prove fatal. If bitten before the proper time at
such a point, the victim becomes putrid, which promptly causes death
by poisoning in the consumer. When diverted from its plan of attack,
deprived of its clue, the larva is not always able to rediscover the
lawful morsels in good time and is killed by the decomposition of its
badly dissected prey. What will happen if the experimenter gives it a
game to which it is not accustomed? Not knowing how to eat it according
to rule, the larva will kill it; and by next day the victuals will have
become so much toxic putrescence. I have already told how I found it
impossible to rear the Two-banded Scolia on Oryctes-larvae, fastened
down to deprive them of movement, or even on Ephippigers, paralysed by
the Languedocian Sphex. In both cases the new diet was accepted without
hesitation, a proof that it suited the nurseling; but in a day or two
putrescence supervened and the Scolia perished on the fetid morsel. The
method of preserving the Ephippiger, so well known to the Sphex, was
unknown to my boarder; in this was enough to convert a delicious food
into poison.
Even so did my other attempts miscarry wretchedly, attempts at feeding
with the single dish consisting of one big head of game to replace the
normal ration. Only one success is recorded in my notebooks, but that
was so difficult that I would not undertake to obtain it a second time.
I succeeded in feeding the larva of the Hairy Ammophila with an adult
black Cricket, who was accepted as readily as the natural game, the
caterpillar.
To avoid putrefaction of victuals which last overlong and are not
consumed according to the method indispensable to their preservation, I
employ small game, each piece of which can be finished by the larva at a
single sitting, or at most in a single day. It matters little then that
the victim is slashed and dismembered at random; decomposition has no
time to seize upon its still quivering tissues. This is the procedure
of those larvae which gulp down their food, snapping at random without
distinguishing one part from another, such as the Bembex-larvae, which
finish the Fly into which they have bitten before beginning another in
the heap, or the Cerceris-larvae, which drain their Weevils methodically
one after another. With the first strokes of the mandibles the victim
broached may be mortally wounded. This is no disadvantage: a brief spell
suffices to make use of the corpse, which is saved from putrefaction by
being promptly consumed. Close beside it, the other victims, quite alive
though motionless, await their respective turns and supply reserves of
victuals which are always fresh.
I am too unskilful a butcher to imitate the Wasp and myself to resort to
paralysis; moreover, the caustic liquid injected into the nerve-centres,
ammonia in particular, would leave traces of smell or flavour which
might put off my boarders. I am therefore compelled to deprive my
insects of the power of movement by killing them outright. This makes
it impracticable to provide a sufficiency of provisions beforehand in a
single supply: while one item of the ration was being consumed the
rest would spoil. One expedient alone remains to me, one which entails
constant attendance: it is to renew the provisions each day. When all
these conditions are fulfilled, the success of artificial feeding is
still not without its difficulties; nevertheless, with a little care and
above all plenty of patience, it is almost certain.
It was thus that I reared the Tarsal Bembex, which eats Anthrax-flies
and other Diptera, on young Locustidae or Mantidae; the Silky Ammophila,
whose diet consists chiefly of Measuring-worms, on small Spiders; the
pot-making Pelopaeus, a Spider-eater, on tender Acridians; the Sand
Cerceris, a passionate lover of Weevils, on Halicti; the Bee-eating
Philanthus, which feeds exclusively on Hive-bees, on Eristales and other
Flies. Without succeeding in my final aim, for reasons which I have just
explained, I have seen the Two-banded Scolia feasting greedily on the
grub of the Oryctes, which was substituted for that of the Cetonia, and
putting up with an Ephippiger taken from the burrow of the Sphex; I have
been present at the repast of three Hairy Ammophilae accepting with an
excellent appetite the Cricket that replaced their caterpillar. One
of them, as I have related, contrived to keep its ration fresh, which
enabled it to reach its full development and to spin its cocoon.
These examples, the only ones to which my experiments have extended
hitherto, seem to me sufficiently convincing to allow me to conclude
that the carnivorous larva does not have exclusive tastes. The ration
supplied to it by the mother, so monotonous, so limited in quality,
might be replaced by others equally to its taste. Variety does not
displease the larva; it does it as much good as uniformity; indeed, it
would be of greater benefit to the race, as we shall see presently.