THE BEE-MILK MYSTERY
AMONG the innumerable scraps of more or less erroneous information on
hive-life, dished up by the popular newspapers in course of the year’s
round, there is occasionally one which is sure to grip the curious
reader’s attention. No one expects nowadays to read of the honey-bee
without being set agape at the marvellous; but, really, when he is
gravely told that the nurse-bees in a hive actually give the breast to
their young, suckling them with a secreted liquid which is nothing more
or less than milk, the ordinarily faithful newspaper student is entitled
to be for once incredulous.
The thing, however, in spite of its grotesque improbability, comes nearer
to the plain truth than many another item of bee-life more often
encountered and unquestionably accepted. There are veritable nurse-bees
in a hive, and these do produce something not unlike milk. In about
three days after the egg has been deposited in the comb-cell by the
queen, or mother-bee, a tiny white grub emerges. The feeding of this
grub is immediately commenced by the bees in charge of the nursery
quarters of the hive, and there is administered to it a glistening white
substance closely resembling thick cream.
Analysts tell us that this bee-milk, as it is called, is highly
nitrogenous in character, and that it has a decidedly acid reaction. It
is obviously produced from the mouths of the nurse-bees, and appears to
be digested matter thrown up from some part of the bee’s internal system,
and combined with the secretions from one or more of the four separate
sets of glands which open into different parts of the worker-bee’s mouth.
The power to secrete this bee-milk seems to be normally limited to those
workers who are under fourteen or fifteen days old. After that time the
bee runs dry, her nursing work is relinquished, and she goes out to
forage for nectar and pollen, never, as far as is known, resuming the
task of feeding the young grubs. But if the faculty is not exercised, it
may be held in abeyance for months together. This takes place at the
close of each year, when we know that the last bees born to the hive in
autumn are those who supply the milk for the first batches of larva
raised in the ensuing spring.
It is difficult to keep out the wonder-weaving mood when writing of any
phase of hive-life, and especially so when we have this bee-milk under
consideration. For all recent studies of the matter tend to prove
several facts about it not merely wonderful, but verging on the
mysterious.
In the first place, its composition seems to be variable at the will of
the bees. The white liquid is supplied to the grubs of worker, queen,
and drone, and not only is its nature different with each, but it is even
possible that this may be farther modified in the various stages of their
development. It is well ascertained that the physical and temperamental
differences between queen and worker-bee, widely marked as they appear,
are entirely due to treatment and feeding during the larval stage. That
the eggs producing the two are identical is proved by the fact that these
can be transposed without confounding the original purpose of the hive.
The queen-egg placed in the worker-cell develops into a common worker,
while the worker-egg, when exalted to a queen’s cradle, infallibly
produces a fully accoutred queen bee. The experiment can also be made
even with the young grubs, provided that these are no more than three
days old, and the same result ensues.
A close study of the food administered to bees when in the larval stage
of their career is specially interesting, because it gives us the key to
many otherwise inexplicable matters connected with hive-life. We do not
know, and probably never shall know, how mere variation in diet causes
certain organs to appear and certain other bodily parts to absent
themselves. If the difference between queen and worker-bee were simply
one of development, the worker being only an undersized, semi-atrophied
specimen of a queen, there would be little mystery about it. But each
has several highly specialised organs, of which the other has no trace,
just as each has certain functions reduced to mere rudimentary
uselessness, which, in the other, possess enormous development and a
corresponding importance.
Clearly the food given in each case has peculiar properties, bringing
about certain definite invariable results. We are able, therefore, to
say positively that most of the classic marvels of bee-life are built up
on this one determined issue, this one logical adjustment of cause and
effect. The hive creates thousands of sexless workers and only one
fertile mother-bee. It limits the number of its offspring according to
the visible food supplies or the needs of the commonwealth. It brings
into existence, when necessity calls for them, hundreds of male bees or
drones, and when their period of usefulness is over it decrees their
extermination. When the queen’s fecundity declines, it raises another
queen to take her place. It can even, under certain rare conditions of
adversity, manufacture what is known as a fertile worker, when some
mischance has deprived it of its mother-bee and the materials for
providing a legitimate successor to her are not forthcoming. And all
these results are primarily brought about by the one means, the one
vehicle of mystery—this wonderful bee-milk playing its part at all stages
in the honey-bee’s life from her cradle to her grave.
For to track down this subtly-compounded elixir through all its various
uses one must take a survey of almost the whole round of activities in
the hive. The food of the young larva, whether of queen or worker, for
the first three days after the eggs are hatched, seems to consist
entirely of bee-milk. The drone-grub gets an extra day of this richly
nitrogenous diet. And for the remaining two days of the grub stage of
the bee’s life milk is given continuously, but, in the case of the worker
and drone, in greatly diminished supply. Its place during these two days
is largely taken, it is said, by honey and digested pollen in the
worker’s instance, and by honey and raw pollen for the males.
The queen-grub alone receives bee-milk, of a specially rich kind and in
unlimited quantity, for the whole of her larval life. This “royal
jelly,” as the old bee-masters termed it, is literally poured into the
capacious queen-cell. For the whole five days of her existence as a
larva she actually bathes in it up to the eyes. But, as far as is known,
she receives no other food during this time. The regular order of her
development, and of that of the worker-bee, during the five days of the
grub stage has been carefully studied, and it is curious to note that the
very time when the queen’s special organs of motherhood begin to show
themselves coincides exactly with the moment at which the worker-grub’s
allowance of bee-milk is cut down and other food substituted.
This, no doubt, explains why these organs in the adult worker-bee are so
elementary as to be practically non-existent, and accounts for the
queen’s generous growth in other directions. But it leaves us completely
in the dark as to the reason for the worker’s subsequent elaboration of
such organs as the pollen-carrying device, the so-called wax-pincers, and
the wax-secreting glands, of which the queen possesses none. Nor are we
able to see how the giving or withholding of the bee-milk should furnish
the queen with a long curved sting and the worker with a short straight
one; nor how mere manipulation of diet can result in making the two so
dissimilar in temperament and mental attributes—the worker laborious,
sociable, almost preternaturally alert of mind, and withal essentially a
creature of the open air and sunshine; the queen dull of intelligence,
possessed of a jealous hatred of her peers, for whom all the light and
colour and fragrance of a summer’s morning have no allurements, a being
whose every instinct keeps her, from year’s end to year’s end, pent in
the crowded tropic gloom of the hive.
But the bee-milk as well as being the main ingredient in the larval food,
has other and almost equally important uses. It is supplied by the
workers to the adult queen and drones throughout nearly the whole of
their lives, and forms an indispensable part of their daily diet. And
this gives us a clue in our attempt to understand, not only how the
population of the hive is regulated, but why the males are so easily
disposed of when the annual drone-massacre sets in. By giving or
depriving her of the bee-milk, the workers can either stimulate the queen
to an enormous daily output of eggs or reduce her fertility to a bare
minimum; and, as for the drones, it is starvation that is the secret of
their half-hearted, feeble resistance to fate.
Yet though we may recount these things, and speak of this mysterious
essence called bee-milk as really the mainspring of all effort and
achievement within the hive, it is doubtful whether we have solved the
greatest mystery of all about it. Of what is it composed, and whence is
it derived? The generally-accepted explanation of its origin is that it
is pollen-chyle regurgitated from the second stomach of the bee, combined
with the secretions from certain glands of the mouth in passing. But the
most careful dissections have never revealed anything like bee-milk in
any part of the bee’s internal system. Its pure white, opaque quality
has absolutely no counterpart there: nor, indeed—if we are to believe
latest investigations—does pollen-chyle exist at all in either the first
or second stomach of the bee, whence alone it could be regurgitated.
Bee-milk, it would seem, is still a physiological mystery, and so may
remain to the end of time.