of queens, of the combats in which they engage, and the animosity that
leads them to destroy one another. Of several royal nymphs in a hive,
the first transformed attacks the rest, and stings them to death. But
were these nymphs enveloped in a complete coccoon, she could not
accomplish it. Why? because the silk is of so close a texture, the sting
could not penetrate, or if it did, the barbs would be retained by the
meshes of the coccoon, and the queen, unable to retract it, would
become the victim of her own fury. Thus, that the queen might destroy
her rivals, it was necessary the last rings of the body should remain
uncovered, therefore the royal nymphs must only form imperfect coccoons.
You will observe, that the last rings alone should be exposed, for the
sting can penetrate no other part: the head and thorax are protected by
connected shelly plates which it cannot pierce.
Hitherto, philosophers have claimed our admiration of nature in her care
of preserving and multiplying the species. But from the facts I relate,
we must admire her precautions in exposing certain individuals to a
mortal danger.
The detail on which I have just entered clearly indicates the final
cause of the opening left by the royal worms in their coccoons; but it
does not shew whether it is in consequence of a particular instinct that
they leave this opening, or whether the wideness of their cells prevents
them from stretching the thread up to the top. This question interested
me very much; the only method of deciding it was to observe the worms
while spinning, which cannot be done in their opaque cells. It then
occurred to me to dislodge them from their own habitations, and
introduce them into glass tubes, blown in exact imitation of the
different kind of cells. The most difficult part of the operation
consisted in extracting worms and introducing them here; but my
assistant accomplished it with much address. He opened several sealed
royal cells, where we knew the larvæ were about to begin their coccoons,
and, taking them gently out, introduced one into each of my glass cells
without the smallest injury.
They soon prepared to work; and commenced by stretching the anterior
part of the body in a straight line, while the other was bent in a
curve. This formed a curve of which the longitudinal sides of the cells
were tangents, and afforded two points of support. The head was next
conducted to the different parts of the cell which it could reach, and
it carpeted the surface with a thick bed of silk. We remarked that the
threads were not carried from one side to another, and that this would
have been impracticable, for the worms being obliged to support
themselves, and to keep the posterior rings curved, the free and
moveable part of the body was not long enough for the mouth to reach the
sides diametrically opposite, and fix the threads to them. You will
remember, Sir, that the royal cells are of a pyramidal form, with a wide
base, and a long contracted top. These cells hang perpendicularly in the
hive, the point downwards, from which position the royal worm can be
supported in the cell, only when the curvature of the posterior part
forms two points of support; and that it cannot obtain this support
without resting on the lower part, or towards the extremity. Therefore
if it attempted to stretch out and spin towards the wide end of the
cell, it could not reach both sides from being too distant. One part
would be touched by its extremity, the other by its back, and it would
consequently tumble down. I have particularly ascertained the fact in
glass cells that were too large, and of which the diameter was greater
towards the point than is usual in cells; there they were unable to
support themselves.
These first experiments obviated the suspicion of any particular
instinct in the royal worms. They proved, if the worms spun incomplete
coccoons, it was because they were forced to do so by the figure of
their cells. However, I wished to have evidence still more direct. I put
them into cylindrical glass cells, or portions of glass tubes resembling
common cells, and I had the satisfaction of seeing them spin complete
coccoons, as the worms of workers do. Lastly, I put common worms in very
wide cells, and they left the coccoon open. Thus it is demonstrated,
that the royal worms, and those of workers, have the same instinct and
the same industry, or in other words, when situated in the same
circumstances, the course they follow is the same. I may here add, that
the royal worms artificially lodged in cells, where they can spin
complete coccoons, undergo all their metamorphoses equally well. Thus
the necessity imposed on them by nature, of having the coccoons open, is
not necessary for their increment; nor has it any other object than that
of exposing them to the certainty of perishing by the wounds of their
natural enemy; an observation new and truly singular.
* * * * *
I ought to relate my experiments on the influence that the size of the
cells has on bees. It is to you, Sir, that I am indebted for suggesting
them.
As we sometimes find males smaller than they ought to be, and also
queens more diminutive than usual, it was desirable to obtain a general
explanation, to what degree the cells, where bees pass the first period
of their existence, influence their size. With this view, you have
advised me to remove all the combs composed of common cells, and to
leave those consisting of large cells only. It was evident if the common
eggs which the queen would lay in these large cells produced workers of
larger size, we were bound to conclude that the size of the cells had a
sensible influence on the size of the bees. The first time I made this
experiment, it did not succeed, because weevils lodged in the hive
discouraged the bees. But I repeated it afterwards, and the result was
very remarkable.
I removed the whole comb, consisting of common cells, from one of my
best glass hives, and left that composed of males' cells alone: and to
avoid vacuities, I supplied others of the same kind. This was in June,
the season most favourable to bees. I expected that the bees would
quickly have repaired the ravages produced by this operation in their
dwelling; that they would labour at the breaches, and unite the new
combs to the old. But I was very much surprised to see that they did not
begin to work. Expecting they would resume their activity, I continued
observing them several days; however, my hopes were disappointed. Their
homage to the queen was not interrupted indeed; but except in this,
their conduct to the queen was quite different from what it usually is;
they clustered on the combs without exciting any sensible heat. A
thermometer among them rose only to 81°, though standing at 77° in the
open air. In a word, they appeared in a state of the greatest
despondency.
The queen herself, though very fertile, and though she must have been
oppressed by her eggs, hesitated long before depositing them in the
large cells; she chose rather to drop them at random than lay in cells
unsuitable. However, on the second day, we found six that had been
deposited there with all regularity. The worms were hatched three days
afterwards, and then we began to study their history. Though the bees
provided them with food, they did not carefully attend to it; yet I was
in hopes they might be reared. I was again disappointed; for next
morning all the worms had disappeared, and their cells were left empty.
Profound silence reigned in the hive; few bees left it, and these
returned without pellets of wax on the limbs; all was cold and
inanimate. To promote a little motion, I thought of supplying the hive
with a comb, composed of large cells, full of male brood of all ages.
The bees, which had twelve days obstinately refused working in wax, did
not unite this comb to their own. However, their industry was awakened
in a way that I had not anticipated. They removed all the brood from
this comb, cleaned out the whole cells, and prepared them for receiving
new eggs. I cannot determine whether they expected the queen to lay, but
it is certain if they did so they were not deceived. From this moment,
she no longer dropped her eggs; but laid such a number in the new comb,
that we found five or six together in the same cell. I then removed all
the combs composed of large cells to substitute small cells in their
place, an operation which restored complete activity among the bees.
The peculiarities of this experiment seem worthy of attention. It proves
that nature does not allow the queen the choice of the eggs she is to
lay. It is ordained that, at a certain time of the year, she shall
produce those of males, and at another time the eggs of workers, and
this order cannot be inverted. We have seen that another fact led me to
the same consequence; and as that was extremely important, I am
delighted to have it confirmed by a new observation. Let me repeat,
therefore, that the eggs are not indiscriminately mixed in the ovaries
of the queen, but arranged so that, at a particular season, she can lay
only a certain kind. Thus, it would be vain at that time of the year,
when the queen should lay the eggs of workers, to attempt forcing her to
lay male eggs, by filling the hives with large cells; for, by the
experiment just described, we learn, that she will rather drop the
workers eggs by chance than deposit them in an unsuitable place; and
that she will not lay the eggs of males. I cannot yield to the pleasure
of allowing this queen discernment or foresight, for I observe a kind of
inconsistency in her conduct. If she refused to lay the eggs of workers
in large cells, because nature has instructed her that their size is
neither proportioned to the size nor necessities of common worms, would
not she also have been instructed not to lay several eggs in one cell?
It seems much easier to rear a worker's worm in a large cell, than to
rear several of the same species in a small one. Therefore, the supposed
discrimination of bees is not very conspicuous. Here the most prominent
feature of industry appears in the common bees. When I supplied them
with a comb of small cells, full of male brood, their activity was
awakened; but instead of bestowing the necessary care on this brood, as
they would have done in every other situation, they destroyed the whole
nymphs and larvæ, and cleaned out their cells, that the queen, now
oppressed with the necessity of laying, might suffer no delay in
depositing her eggs. Could we allow them either reason or reflection,
this would be an interesting proof of their affection for her.
The experiment, now detailed at length, not having fulfilled my object
in determining the influence of the size of the cells on that of the
worms, I invented another which proved more successful.
Having selected a comb of large cells, containing the eggs and worms of
males, I removed all the worms from their farina, and my assistant
substituted those of workers a day old in their place. Then he
introduced this comb into a hive that had the queen. The bees did not
abandon these substituted worms; they covered their cells with a top
almost flat, a kind quite different from what is put on the cells of
males; which proves, that they were well aware that these, though
inhabiting large cells, were not males. This comb remained eight days
in the hive, counting from the time the cells were sealed. I then
removed it to examine the included nymphs, which proved those of workers
in different stages of advancement; but, as to size and figure, they
perfectly resembled what had grown in the smallest cells. I thence
concluded, that the larvæ of workers do not acquire greater size in
large than in small cells. Although this experiment was made only once,
it seems decisive. Nature has appropriated cells of certain dimensions
for the worms of workers while in their vermicular state; undoubtedly
she has ordained that their organs should be fully expanded, and there
is sufficient space for that purpose; therefore more would be useless.
Their expansion ought to be no greater in the most spacious cells than
in those appropriated for them. If some cells smaller than common ones
are found in combs, and the eggs of workers are deposited there, the
size of the bees will probably be less than that of common workers,
because they have been cramped in the cells; but it does not thence
ensue, that a larger cell will admit of them growing to a greater size.
The effect produced on the size of drones by the size of the cells their
worms inhabit, may serve as a rule for what should happen to the larvæ
of workers in the same circumstances. The large cells of males are
sufficiently capacious for the perfect expansion of their organs. Thus,
although reared in cells of still greater capacity, they will grow no
larger than common drones. We have had evidence of this in those
produced by queens whose fecundation has been retarded. You will
remember, Sir, that they sometimes lay male eggs in the royal cells.
Now, the males proceeding from them, and reared in cells much more
spacious than nature has appropriated for them, are no larger than
common males. Therefore it is certain, that whatever be the size of the
cells where the worms acquire their increment, the bees will attain no
greater size than is peculiar to their species. But if, in their primary
form, they live in cells smaller than they should be, as their growth
will be checked, they will not attain the usual size, of which there is
proof in the following experiment. I had a comb consisting of the cell
of large drones, and one with those of workers, which also served for
the male worms. Of these, my assistant took a certain number from the
smallest cells, and deposited them on a quantity of food purposely
prepared in the large ones; and in return he introduced into the small
cells the worms that had been hatched in the other, and then committed
both to the care of the workers in a hive where the queen laid the eggs
of males only. The bees were not affected by this change; they took
equal care of the worms; and when the period of metamorphosis arrived,
gave both kinds that convex covering usually put on those of the males.
Eight days afterwards, we removed the combs, and found, as I had
expected, nymphs of large males in the large cells, and those of small
males in the small ones.
You suggested another experiment which I carefully made, but it met with
an unforeseen obstacle. To appreciate the influence of the royal food on
the expansion of the worms, you desired me to supply the worm of a
worker in a common cell with it. Twice I have attempted this operation
without success. Nor do I think it can ever succeed. If bees get the
charge of worms, in whose cells the royal food is deposited, and if at
the same time they have a queen, they soon remove the worms and greedily
devour the food. When, on the contrary, they are deprived of a queen,
they change the cells containing worms into cells of the largest kind.
Then the worms will infallibly be converted to queens.
But there is another situation where we can judge of the influence of
the royal food administered to worms in common cells. I have spoken at
great length in my letter on the existence of fertile workers. You
cannot forget, Sir, that the expansion of their sexual organs is owing
to the reception of some particles of royal jelly, while in the
vermicular form. For want of new observations, I must refer you to what
is previously said on the subject.
_PREGNY, 4 September 1791._
LETTER IX.
_ON THE FORMATION OF SWARMS._
I can add but a few facts to the information M. de Reaumur has
communicated relative to swarms.
A young queen, according to this celebrated naturalist, is always or
almost always at the head of a swarm; but he does not assert the fact
positively, and had some doubts on the subject. "Is it certain," says
he "as we have hitherto supposed, in coincidence with all who have
treated of bees, that the new colony is always conducted by a young
mother? May not the old mother be disgusted with her habitation? or may
she not be influenced by some particular circumstances to abandon all
her possessions to the young female? I wish it had been in my power to
solve this question otherwise than by mere probabilities, and that some
misfortune had not befallen all the bees whose queen I had marked red on
the thorax."
These expressions seem to indicate, that M. de Reaumur suspected that
the old queens sometimes conducted the young swarms. By the following
details, you will observe, that his suspicions are fully justified.
In the course of spring and summer, the same hive may throw several
swarms. The old queen is always at the head of the first colony; the
others are conducted by young queens. Such is the fact which I shall now
prove; and the peculiarities attending it shall be related.
But previous to entering on this subject, I should repeat what has
already been frequently observed, that the _leaf_ or flat hives are
indispensible in studying the industry and instinct of bees. When they
are left at liberty to conduct several rows of parallel combs, we can no
longer observe what is continually passing between them, or they must be
dislodged by water or smoke, for examining what has been constructed; a
violent proceeding, which has a material influence on their instinct,
and consequently exposes an observer to the risk of supposing simple
accidents permanent laws.
I now proceed to experiments proving that an old queen always conducts
the first swarm.
One of my glass hives consisted of three parallel combs, placed in
squares that opened like the leaves of a book. It was well peopled and
abundantly provided with honey, wax, and brood, of every age. On the
fifth of May 1788, I removed the queen, and on the sixth, transferred
all the bees into another hive, with a fertile queen at least a year
old. They entered easily and without fighting, and were in general well
received. The old inhabitants of the hive, which, since privation of
their queen, had begun twelve royal cells, also gave the fertile queen a
good reception; they presented her with honey, and formed regular
circles around her. However, there was a little agitation in the
evening, but confined to the surface of the comb where we had put the
queen, and which she had not quitted. All was perfectly quiet on the
other side of this comb.
In the morning of the seventh, the bees had destroyed the twelve royal
cells, but, independent of that, order continued prevalent in the hive;
the queen laid the eggs of males in the large cells, and those of
workers in the small ones, respectively.
Towards the twelfth, we found the bees occupied in constructing
twenty-two royal cells, of the same species described by M. de Reaumur,
that is the bases not in the plane of the comb, but appended
perpendicularly by pedicles or stalks of different length, like
stalactites, on the edge of the passage made by the bees through their
combs. They bore considerable resemblance to the cup of an acorn, and
the longest were only about two lines and a half in depth from the
bottom to the orifice.
On the thirteenth, the queen seemed already more slender than when
introduced into the hive; however she still laid some eggs, both in
common cells and those of males. We also surprised her this day laying
in a royal cell: she first dislodged the worker there employed, by
pushing it away with her head, and then supported herself by the
adjoining cells while depositing the egg.
On the fifteenth, the queen was still more slender: the bees continued
their attention to the royal cells, which were all unequally advanced;
some to three or four lines in height, while others were already an inch
long; which proved that the queen had not laid in the whole at the same
time.
At the moment when least expected, the hive swarmed on the nineteenth;
we were warned of it by the noise in the air; and hastened to collect
and put the bees into a hive purposely prepared. Though we had
overlooked the facts attending the departure of the swarm, the object of
this experiment was fulfilled; for, on examination of all the bees, we
were convinced they had been conducted by the old queen; by that we
introduced on the sixth of the month, and which had been deprived of one
of the antennæ. Observe, there was no other queen in this colony. In the
hive she had left, we found seven royal cells close at the top, but open
at the side, and quite empty. Eleven more were sealed; and some others
newly begun; no queen remained in the hive.
The new swarm next became the object of our attention: we observed it
during the rest of the year, during winter and the subsequent spring;
and, in April, we had the satisfaction of seeing a new swarm depart with
the same queen at its head that had conducted the former swarm in May
the preceding year.
You will remark, Sir, that this experiment is positive. We put an old
queen in a glass hive while laying the eggs of males. The bees received
her well, and at that time began to construct royal cells; she laid in
one of them before us; and in the last place led forth the swarm.
We have several times repeated the same experiment with equal success.
Thus it appears incontestible, that the old queen always conducts the
first swarm; but never quits the hive before depositing eggs in the
royal cells, from which other queens will proceed after her departure.
The bees prepare these cells only while the queen lays male eggs; and a
remarkable fact attends it, that after this laying terminates, her belly
being considerably diminished, she can easily fly, whereas, her belly is
previously so heavy she can hardly drag it along. Therefore it is
necessary she should lay in order to be in a condition for undertaking
her journey, which may sometimes be very long.
But this single condition is not enough. It is also requisite that the
bees be very numerous: they should even be superabundant, and a person
might say they are aware of it: for, if the hive is thin, no royal cells
are constructed when the male eggs are laid, which is solely at the
period that the queen is able to conduct a colony. This fact was proved
by the following experiment on a large scale.
On the third of May 1788, we divided eighteen hives into two portions;
all the queens were about a year old. Thus each portion of the hives
had but half the bees that were originally there. Eighteen halves wanted
queens, but the other eighteen had very fertile ones. They soon began to
lay the eggs of males; but, the bees being few, they did not construct
royal cells, and none of the hives threw a swarm.--Therefore, if the
hive containing the old queen is not very populous, she remains in it
until the subsequent spring; and if the population is then sufficient,
royal cells will be constructed: the queen will begin to lay male eggs,
and, after depositing them, will issue forth at the head of a colony,
before the young queens are produced.
Such is a very brief abstract of my observations on swarms conducted by
old queens. You must excuse the long detail on which I am about to
enter, concerning the history of the royal cells left by the queen in
the hive. Every thing relative to this part of the history of bees has
hitherto been very obscure. A long course of observations, protracted
even during several years, was necessary to remove, in some degree, the
veil that concealed these mysteries. I have been indemnified for the
trouble, indeed, by the pleasure of seeing my experiments reciprocally
confirmed; but, considering the assiduity required in these researches,
they were truly very laborious.
Having established in 1788 and 1789, that queens a year old conducted
the first swarm, and that they left worms or nymphs in the hive to
transform into queens in their turn; I endeavoured, in 1790, to profit
by the goodness of the spring, to study all that related to these young
queens; and I shall now extract the chief experiments from my journal.
On the fourteenth of May, we introduced two portions of bees, from the
straw hives, into a large glass hive very flat; and allowed them only
one queen of the preceding year, and which had already commenced laying
in its native hive. We introduced her on the fifteenth. She was very
fertile. The bees received her well, and she soon began to lay in large
and small cells alternately.
On the twentieth, we saw the formation of twelve royal cells, all on the
edges of the communications, or passages through the combs, and shaped
liked stalactites.
On the twenty-seventh, ten were much but unequally enlarged; but none so
long as when the worms are hatched.