and instinct seem concerned, but the former more decidedly, may be
cited the account which Huber gives of the manner in which the bees
of some of his neighbours protected themselves against the attacks
of the death's-head-moth (_Acherontia Atropos_), laid before you in
a former letter[806], by so closing the entrance of the hive with
walls, arcades, casements, and bastions, built of a mixture of wax
and propolis, that these insidious marauders could no longer intrude
themselves.
We can scarcely attribute these elaborate fortifications to reason
simply; for it appears that bees have recourse to a similar defensive
expedient when attacked even by other bees; and the means employed
seem too subtle and too well adapted to the end to be the result of
this faculty in a bee.
But on the other hand, if it be most probable that in this instance
instinct was chiefly concerned, if we impartially consider the
facts, it seems impossible to deny that reason had some share in
the operations. Pure instinct would have taught the bees to fortify
themselves on the _first_ attack. If the occupants of a hive had been
taken unawares by these gigantic aggressors one night, on the second,
at least, the entrance should have been barricadoed. But it appears
clear from the statement of Huber, that it was not until the hives
had been repeatedly attacked and robbed of nearly their whole stock
of honey, that the bees betook themselves to the plan so successfully
adopted for the security of their remaining treasures; so that
reason taught by experience, seems to have called into action their
dormant instinct[807].
If it be thus probable that reason has some influence upon the
actions of insects, which must be mainly regarded as instinctive, the
existence of this faculty is still more evident in numerous traits
of their history where instinct is little if at all concerned. An
insect is taught by its instincts the most unerring means to the
attainment of certain ends; but these ends, as I have already had
occasion more than once to remark, are limited in number, and such
only as are called for by its wants in a state of nature. We cannot
reasonably suppose insects to be gifted with instincts adapted for
occasions that are never likely to happen. If therefore we find them,
in these extraordinary and improbable emergencies, still availing
themselves of the means apparently best calculated for ensuring their
object;--and if in addition they seem in some cases to gain knowledge
by experience; if they can communicate information to each other; and
if they are endowed with memory;--it appears impossible to deny that
they are possessed of reason.--I shall now produce facts in proof of
each of these positions; not by any means all that might be adduced,
but a few of the most striking that occur to me.
* * * * *
First, then, insects often in cases not likely to be provided for by
instinct, adopt means evidently designed for effecting their object.
A certain degree of warmth is necessary to hatch a hen's eggs, and
we give her little credit for reason in sitting upon them for this
purpose. But if any one had ever seen a hen make her nest in a heap
of fermenting dung, among the bark of a hot-bed, or in the vicinity
of a baker's oven, where, the heat being as well adapted as the
stoves of the Egyptians to bring her chickens into life, she left off
the habit of her race, and saved herself the trouble of sitting upon
them,--we should certainly pronounce her a _reasoning_ hen: and if
this hen had chanced to be that very one figured and so elaborately
described by Professor Fischer, with _the profile of an old
woman_[808], a Hindoo metaphysician at least could not doubt of her
body, however hen-like, being in truth directed in its operations by
the soul of some quondam amateur of poultry-breeding. Now societies
of ants have more than once exhibited a deviation from their usual
instinct, which to me seems quite as extraordinary and as indicative
of reason as would be that supposed in a hen. A certain degree of
warmth is required for the exclusion and rearing of their eggs, larvæ
and pupæ; and in their ordinary abodes, as you have been already
told[809], they undergo great daily labour in removing their charge
to different parts of the nest, as its temperature is affected by the
presence or absence of the sun. But Reaumur, in refuting the common
notion of ants being injurious to bees, tells us that societies of
the former often saved themselves all this trouble, by establishing
their colonies between the exterior wooden shutters and panes of his
glass hives, where, owing to the latter substance being a tolerably
good conductor of heat, their progeny was at _all times_, and
without any necessity of changing their situation, in a constant,
equable, and sufficient temperature[810]. Bonnet observed the same
fact. He found that a society of ants had piled up their young to the
height of several inches, between the flannel-lined case of his glass
hives and the glass. When disturbed they ran away with them, but
always replaced them[811].
I am persuaded that after duly considering these facts, you will
agree with me that it is impossible consistently to refer them to
instinct, or to account for them without supposing some stray ant,
that had insinuated herself into this tropical crevice, first to
have been struck with the _thought_ of what a prodigious saving of
labour and anxiety would occur to her compatriots by establishing
their society here;--that she had communicated her _ideas_ to
them;--and that they had resolved upon an emigration to this
new-discovered country--this Madeira of ants--whose genial clime
presented advantages which no other situation could offer. Neither
instinct, nor any conceivable modification of instinct, could have
taught the ants to avail themselves of a good fortune which but for
the invention of glass hives would never have offered itself to a
generation of these insects since the creation; for there is nothing
analogous in nature to the constant and equable warmth of such a
situation, the heat of any accidental mass of fermenting materials
soon ceasing, and no heat being given out from a society of bees when
lodged in a hollow tree, their natural residence. The conclusion,
then, seems irresistible, that reason must have been their guide,
inducing a departure from their natural instinct as extraordinary as
would be that of a hen which should lay her eggs in a hot-bed, and
cease to sit upon them.
The adaptation of means to an end not likely to have been provided
for by instinct, is equally obvious in the ingenious mode by which a
nest of humble-bees propped up their tottering comb, the particulars
of which having before mentioned to you[812], I need not here repeat.
There is perhaps no surer criterion of reason than, after having tried
one mode of accomplishing a purpose, adopting another more likely to
succeed. Insects are able to stand this test. A bee which Huber watched
while soldering the angles of a cell with propolis, detached a thread
of this material with which she entered the cell. Instinct would have
taught her to separate it of the exact length required; but after
applying it to the angle of the cell, she found it too long, and cut
off a portion so as to fit it to her purpose[813].
This is a very simple instance; but one such fact is as decisive in
proof of reason as a thousand more complex, and of such there is no
lack. Dr. Darwin (whose authority in the present case depending not
on hearsay, but his own observation, may be here taken,) informs
us, that walking one day in his garden he perceived a wasp upon
the gravel walk with a large fly nearly as big as itself which it
had caught. Kneeling down he distinctly saw it cut off the head
and abdomen, and then taking up with its feet the trunk or middle
portion of the body to which the wings remained attached, fly away.
But a breeze of wind acting upon the wings of the fly turned round
the wasp with its burthen, and impeded its progress. Upon this it
alighted again on the gravel walk, deliberately sawed off first one
wing and then the other; and having thus removed the cause of its
embarrassment, flew off with its booty[814]. Could any process of
ratiocination be more perfect? "Something acts upon the wings of this
fly and impedes my flight. If I wish to reach my nest quickly, I must
get rid of them--to effect which, the shortest way will be to alight
again and cut them off." These reflections, or others of similar
import, must be supposed to have passed through the mind of the wasp,
or its actions are altogether inexplicable. Instinct might have
taught it to cut off the wings of _all_ flies, previously to flying
away with them. But here it first attempted to fly with the wings
on,--was impeded by a certain cause,--discovered what this cause
was,--and alighted to remove it. The chain of evidence seems perfect
in proof that nothing but reason could have been its prompter.
An analogous though less striking fact is mentioned by Reaumur on
the authority of M. Cossigny, who witnessed it in the Isle of France
where the _Sphecina_ are accustomed to bury the bodies of cockroaches
along with their eggs for provision for their young. He sometimes saw
an insect of this tribe attempt to drag after it into its hole a dead
cockroach, which was too big to be made to enter by all its efforts.
After several ineffectual trials the animal came out, cut off its
elytra and some of its legs, and thus reduced in compass drew in its
prey without difficulty[815].
Under this head I shall mention but one fact more.--A friend of
Gleditsch the observer of the singular economy of the burying beetle
(_Necrophorus Vespillo_) related in a former letter[816], being
desirous of drying a dead toad, fixed it to the top of a piece of
wood which he stuck into the ground. But a short time afterwards,
he found that a body of these indefatigable little sextons had
circumvented him in spite of his precautions. Not being able to reach
the toad, they had undermined the base of the stick until it fell,
and then buried both stick and toad[817].
* * * * *
In the second place, insects gain knowledge from _experience_, which
would be impossible if they were not gifted with some portion of
reason. In proof of their thus profiting, I shall select from the
numerous facts that might be brought forward, two only, one of which
has been already slightly adverted to[818].
M. P. Huber, in his valuable paper in the sixth volume of the
_Linnean Transactions_[819], states that he has seen large
humble-bees, when unable from the size of their head and thorax
to reach to the bottom of the long tubes of the flowers of beans,
go directly to the calyx, pierce it as well as the tube with the
exterior horny parts of their proboscis, and then insert their
proboscis itself into the orifice and abstract the honey. They
thus flew from flower to flower, piercing the tubes from without,
and sucking the nectar, while smaller humble-bees or those with a
longer proboscis entered in at the top of the corolla. Now from this
statement it seems evident, that the larger bees did not pierce the
bottoms of the flowers until they had ascertained by trial that
they could not reach the nectar from the top; but that having once
ascertained by experience that the flowers of beans are too strait
to admit them, they then, without further attempts in the ordinary
way, pierced the bottoms of _all_ the flowers which they wished to
rifle of their sweets.--M. Aubert du Petit-Thouars observed that
humble-bees and the carpenter-bee (_Xylocopa_[820] _violacea_) gained
access in a similar manner to the nectar of _Antirrhinum Linaria_ and
_majus_, and _Mirabilis Jalappa_; as do the common bees of the Isle
of France to that of _Canna indica_[821]; and I have myself more than
once noticed holes at the base of the long nectaries of _Aquilegia
vulgaris_, which I attribute to the same agency.
My second fact is supplied by the same ants, whose sagacious choice
of the vicinity of Reaumur's glass hives for their colony has been
just related to you. He tells us that of these ants, of which
there were such swarms on the outside of the hive, not a single
one was ever perceived within; and infers that, as they are such
lovers of honey, and there was no difficulty in finding crevices
to enter in at, they were kept without, solely from fear of the
consequences[822]. Whence arose this fear? We have no ground for
supposing ants endowed with any instinctive dread of bees; and
Reaumur tells us, that when he happened to leave in his garden, hives
of which the bees had died, the ants then never failed to enter them
and regale themselves with the honey. It seems reasonable, therefore,
to attribute it to experience. Some of the ants no doubt had tried to
enter the peopled as they did the empty hive, but had been punished
for their presumption, and the dear-bought lesson was not lost on
the rest of the community.
* * * * *
Insects, in the third place, are able mutually to _communicate_ and
_receive information_, which, in whatever way effected, would be
impracticable if they were devoid of reason. Under this head it is
only necessary to refer you to the endless facts in proof, furnished
by almost every page of my letters on the history of ants and of
the hive-bee. I shall therefore but detain you for a moment with an
additional anecdote or two, especially with one respecting the former
tribe, which is valuable from the celebrity of the relater.
Dr. Franklin was of opinion that ants could communicate their ideas
to each other; in proof of which he related to Kalm, the Swedish
traveller, the following fact. Having placed a pot containing treacle
in a closet infested with ants, these insects found their way into
it, and were feasting very heartily when he discovered them. He then
shook them out and suspended the pot by a string from the ceiling.
By chance one ant remained, which, after eating its fill, with some
difficulty found its way up the string, and thence reaching the
ceiling, escaped by the wall to its nest. In less than half an hour a
great company of ants sallied out of their hole, climbed the ceiling,
crept along the string into the pot, and began to eat again. This
they continued until the treacle was all consumed, one swarm running
up the string while another passed down[823]. It seems indisputable
that the one ant had in this instance conveyed news of the booty to
his comrades, who would not otherwise have at once directed their
steps in a body to the only accessible route.
A German artist, a man of strict veracity, states that in his journey
through Italy he was an eye-witness to the following occurrence.
He observed a species of Scarabæus (_Ateuchis pilularius?_) busily
engaged in making, for the reception of its egg, a pellet of dung,
which when finished it rolled to the summit of a small hillock, and
repeatedly suffered to tumble down its side, apparently for the sake
of consolidating it by the earth which each time adhered to it. During
this process the pellet unluckily fell into an adjoining hole, out of
which all the efforts of the beetle to extricate it were in vain. After
several ineffectual trials, the insect repaired to an adjoining heap
of dung, and soon returned with three of his companions. All four now
applied their united strength to the pellet, and at length succeeded in
pushing it out; which being done, the three assistant beetles left the
spot and returned to their own quarters[824].
* * * * *
Lastly, insects are endowed with _memory_, which (at least in
connexion with the purposes to which it is subservient) implies some
degree of reason also; and their historian may exclaim with the poet
who has so well sung the pleasures of this faculty,
Hail, MEMORY, hail! thy universal reign
Guards the least link of Being's glorious chain.
In the elegant lines in which this couplet occurs[825], which were
pointed out to me by my friend Dr. Alderson of Hull, Mr. Rogers
supposes the bee to be conducted to its hive by retracing the scents
of the various flowers which it has visited: but this idea is more
poetical than accurate, bees, as before observed[826], flying
straight to their hives from great distances. Here, as I have more
than once had occasion to remark in similar instances, we have to
regret the want of more correct entomological information in the
poet, who might have employed with as much effect, the real fact of
bees distinguishing their own hives out of numbers near them, when
conducted to the spot by instinct. This recognition of home seems
clearly the result of memory; and it is remarkable that bees appear
to recollect their own hive rather from its situation, than from any
observations on the hive itself[827]: just as a man is guided to his
house from his memory of its position relative to other buildings or
objects, without its being necessary for him even to cast a look at
it. If, after quitting my house in a morning, it were to be lifted
out of its site in the street by enchantment, and replaced by another
with a similar entrance, I should probably, even in the day time,
enter it, without being struck by the change; and bees, if during
their absence their old hive be taken away, and a similar one set in
its place, enter this last, and if it be provided with brood comb
contentedly take up their abode in it, never troubling themselves to
inquire what has become of the identical habitation which they left
in the morning, and with the inhabitants of which, if it be removed
to fifty paces distance, they never resume their connexion[828].
If, pursuing my illustration, you should object that no man would
thus contentedly sit down in a new house without searching after the
old one, you must bear in mind that I am not aiming to show that bees
have as precise a memory as ours, but only that they are endowed
with some portion of this faculty, which I think the above fact
proves. Should you view it in a different light, you will not deny
the force of others that have already been stated in the course of
our correspondence: such as the mutual greetings of ants of the same
society when brought together after a separation of four months[829];
and the return of a party of bees in spring to a window where in
the preceding autumn they had regaled on honey, though none of this
substance had been again placed there[830].
But the most striking fact evincing the memory of these last-mentioned
insects has been communicated to me by my intelligent friend Mr.
William Stickney, of Ridgemont, Holderness. About twenty years ago, a
swarm from one of this gentleman's hives took possession of an opening
beneath the tiles of his house, whence, after remaining a few hours,
they were dislodged and hived. For many subsequent years, when the
hives descended from this stock were about to swarm, a considerable
party of scouts were observed for a few days before to be reconnoitring
about the old hole under the tiles; and Mr. Stickney is persuaded,
that if suffered they would have established themselves there. He is
certain that for eight years successively the descendants of the very
stock that first took possession of the hole frequented it as above
stated, and _not_ those of any other swarms; having constantly noticed
them, and ascertained that they were bees from the original hive by
powdering them while about the tiles with yellow ochre, and watching
their return. And even at the present time there are still seen every
swarming season about the tiles, bees, which Mr. Stickney has no doubt
are descendants from the original stock.
Had Dr. Darwin been acquainted with this fact, he would have adduced
it as proving that insects can convey traditionary information from
one generation to another; and at the first glance the circumstance
of the descendants of the same stock retaining a knowledge of the
same fact for twenty years, during which period there must have been
as many generations of bees, would seem to warrant the inference.
But as it is more probable that the party of surveying scouts of
the first generation was the next year accompanied by others of a
second, who in like manner conducted their brethren of the third, and
these last again others of the fourth generation, and so on,--I draw
no other conclusion from it than that bees are endowed with memory,
which I think it proves most satisfactorily.
I am, &c.
FOOTNOTES:
[760] _Hist. Nat._ Edit. 1785, v. 277.
[761] _Beiträge zur innern Naturgeschichte der Erde_ 1801. p. 298.
[762] In his _Philosophie Zoologique_, Paris 1809 (ii. 325)--a work
which every zoologist will, I think, join with me in regretting
should be devoted to metaphysical disquisitions built on the
most gratuitous assumptions, instead of comprising that luminous
generalization of _facts_ relative to the animal world which is so
great a desideratum, and for performing which satisfactorily this
eminent naturalist is so well qualified.
[763] Dr. Zinken genannt Sommer says, that if in August and September a
snuff-box be left open, it will be seen to be frequented by the common
house-fly (_Musca domestica_), the eggs of which will be found to have
been deposited amongst the snuff. Germar _Mag. der Ent._ I. ii. 189.
[764] Sturm, _Deutschlands Fauna_, i. 27.
[765] _Œuvres_ ii. 238. See above, p. 256.
[766] _Apis._ * *. e. 2. K.
[767] _Linn. Trans._ vi. 254--.
[768] Lyonet, _Traité anatomique_ &c. 16--.
[769] VOL. I. 455--.
[770] Reaum. iii. 112-119.
[771] VOL. I. 172.
[772] _Œuvres_, ix. 370.
[773] Huber, ii. 134--.
[774] Ibid. ii. 216.
[775] Huber, i. 348.
[776] Ibid. ii. 227.
[777] Ibid. i. 119.
[778] Huber, i. 233.
[779] Ibid. ii. 239.
[780] Ibid. ii. 240.
[781] Huber, ii. 280.
[782] Ibid. ii. 284, note *.
[783] Huber, ii. 228.
[784] Huber, ii. 221-226. 244-247.
[785] Ibid. ii. 226.
[786] Huber, ii. 230.
[787] Huber, ii. 219--.
[788] _Œuvres_, ix. 159.
[789] VOL. I. 487--.
[790] See above, p. 186.
[791] Huber, ii. 102.
[792] Ibid. i. 186. ii. 412.
[793] Ibid. ii. 264--. VOL. I. 497.
[794] Huber, ii. 274.
[795] Huber, ii. 275--.
[796] See above, p. 179.
[797] Huber, i. 356.
[798] Ibid. ii. 367.
[799] The following striking anecdote of this last species of instinct
in an animal not famed for sagacity, was related to me by Lieutenant
Alderson, (royal engineers,) who was personally acquainted with the
facts.--In March 1816 an ass, the property of Captain Dundas, R.N.,
then at Malta, was shipped on board the Ister frigate, Captain Forrest,
bound from Gibraltar for that island. The vessel having struck on some
sands off the Point de Gat, at some distance from the shore, the ass
was thrown overboard to give it a chance of swimming to land--a poor
one, for the sea was running so high that a boat which left the ship
was lost. A few days afterwards, however, when the gates of Gibraltar
were opened in the morning, the ass presented himself for admittance,
and proceeded to the stable of Mr. Weeks, a merchant, which he had
formerly occupied, to the no small surprise of this gentleman, who
imagined that from some accident the animal had never been shipped on
board the Ister. On the return of this vessel to repair, the mystery
was explained; and it turned out that Valiante (so the ass was called)
had not only swam safely to shore, but, without guide, compass, or
travelling map, had found his way from Point de Gat to Gibraltar, a
distance of more than two hundred miles, which he had never traversed
before, through a mountainous and intricate country, intersected by
streams, and in so short a period that he could not have made one false
turn. His not having been stopped on the road was attributed to the
circumstance of his having been formerly used to whip criminals upon,
which was indicated to the peasants, who have a superstitious horror of
such asses, by the holes in his ears, to which the persons flogged were
tied.
[800] Huber, ii. 64.
[801] Ibid. ii. 138.
[802] See above, p. 171--.
[803] See above, p. 127--.
[804] Huber, ii. 219.
[805] Hume's _Essay on the Reason of Animals_.
[806] See above, p. 263--.
[807] Huber, ii. 289--.
[808] See Fischer's _Beschreibung eines Huhns mit menschenähnlichem
Profile_, 8vo, St. Petersburg 1816, and a translation in Thomson's
_Annals of Phil._ viii. 241.
[809] VOL. I. 366.
[810] Reaum. v. 709.
[811] _Œuvres_, ii. 416.
[812] VOL. I. 380.
[813] Huber, ii. 268.
[814] _Zoonomia_, i. 183.
[815] Reaum. vi. 283.
[816] VOL. I. 352.
[817] Gleditsch _Physic. Bot. Œcon. Abhandl._ iii. 220.
[818] See above, p. 117.
[819] p. 222.
[820] _Apis_ * *. d. 2. β. K.
[821] _Nouveau Bulletin des Sciences_, i. 45.
[822] Reaum. v. 709.