be broken almost entirely in pieces they will not abandon it[699],
yet when the cold weather approaches, a melancholy change ensues,
followed by a cruel catastrophe, which at first you will be apt to
regard as ill comporting with this affectionate character. As soon
as the first sharp frost of October has been felt, the exterior
of a wasp's nest becomes a perfect scene of horror. The old wasps
drag out of the cells all the grubs and unrelentingly destroy
them, strewing their dead carcases around the door of their now
desolate habitation. "What monsters of cruelty!" I hear you exclaim,
"what detestable barbarians!" But be not too hasty. When you have
coolly considered the circumstances of the case, you will view this
seemingly cruel sacrifice in a different light. The old wasps have
no stock of provisions: the benumbing hand of Winter is about to
incapacitate them from exertion; while the season itself affords
no supply. What resource then is left? Their young must linger on
a short period, suffering all the agonies of hunger, and at length
expire. They have it in their power at least to shorten the term of
this misery--to cut off its bitterest moments. A sudden death by
their own hands is comparatively a merciful stroke. This is the only
alternative; and thus, in fact, this apparent ferocity is the last
effort of tender affection, active even to the end of life. I do not
mean to say that this train of reasoning actually passes through the
mind of the wasps. It is more correct to regard it as having actuated
the benevolent Author of the instinct so singularly, and without
doubt so wisely, excited. Were a nest of wasps to survive the winter,
they would increase so rapidly, that not only would all the bees,
flies, and other animals on which they prey, be extirpated, but man
himself find them a grievous pest. It is necessary, therefore, that
the great mass should annually perish; but that they may suffer as
little as possible, the Creator, mindful of the happiness of the
smallest of his creatures, has endowed a part of the society, at the
destined time, with the wonderful instinct which, previously to their
own death, makes them the executioners of the rest.
Wasps in the construction of their nests have solely in view the
accommodation of their young ones; and to these their cells are
exclusively devoted. _Bees_, on the contrary, (I am speaking of the
common hive-bee,) appropriate a considerable number of their cells to
the reception of honey intended for the use of the society. Yet the
education of the young brood is their chief object, and to this they
constantly sacrifice all personal and selfish considerations. In a
new swarm the first care is to build a series of cells to serve as
cradles; and little or no honey is collected until an ample store of
_bee-bread_, as it is called, has been laid up for their food. This
bee-bread is composed of the pollen of flowers, which the workers
are incessantly employed in gathering, flying from flower to flower,
brushing from the stamens their yellow treasure, and collecting it
in the little baskets with which their hind legs are so admirably
provided; then hastening to the hive, and having deposited their
booty, returning for a new load. The provision thus furnished by
one set of labourers is carefully stored up by another, until the
eggs which the queen-bee has laid, and which adhering by a glutinous
covering she places nearly upright in the bottom of the cell, are
hatched. With this bee-bread after it has undergone a conversion into
a sort of whitish jelly by being received into the bee's stomach,
where it is probably mixed with honey[700] and regurgitated, the
young brood immediately upon their exclusion, and until their change
into nymphs, are diligently fed by other bees, which anxiously attend
upon them and several times a day afford a fresh supply. Different
bees are seen successively to introduce their heads into the cells
containing them, and after remaining in that position some moments,
during which they replace the expended provision, pass on to those
in the neighbourhood. Others often immediately succeed, and in like
manner put in their heads as if to see that the young ones have
every thing necessary; which being ascertained by a glance, they
immediately proceed, and stop only when they find a cell almost
exhausted of food. That the office of these purveyors is no very
simple affair will be admitted, when it is understood that the food
of all the grubs is not the same, but that it varies according to
their age, being insipid when they are young, and, when they have
nearly attained maturity, more sugary and somewhat acid. The larvæ
destined for queen-bees, too, require a food altogether different
from that appropriated to those of drones and workers. It may be
recognised by its sharp and pungent taste.
So accurately is the supply of food proportioned to the wants of the
larvæ, that when they have attained their full growth and are ready
to become nymphs, not an atom is left unconsumed. At this period,
intuitively known to their assiduous foster-parents, they terminate
their cares by sealing up each cell with a lid of wax, convex in
those containing the larvæ of drones, and nearly flat in those
containing the larvæ of workers, beneath which the inclosed tenants
spin in security their cocoon.--In all these labours neither the
queen nor the drones take the slightest share. They fall exclusively
upon the workers, who, constantly called upon to tend fresh broods,
as those brought to maturity are disposed of, devote nearly the whole
of their existence to these maternal offices.
_Humble-bees_[701], which in respect of their general policy must,
when compared with bees and wasps, be regarded as rude and untutored
villagers, exhibit nevertheless marks of affection to their young
quite as strong as their more polished neighbours. The females, like
those of wasps, take a considerable share in their education. When
one of them has with great labour constructed a commodious waxen
cell, she next furnishes it with a store of pollen moistened with
honey; and then having deposited six or seven eggs, carefully closes
the orifice and minutest interstices with wax. But this is not the
whole of her task. By a strange instinct, which, however, may be
necessary to keep the population within due bounds, the workers,
while she is occupied in laying her eggs, endeavour to seize them
from her, and, if they succeed, greedily devour them. To prevent this
violence, her utmost activity is scarcely adequate; and it is only
after she has again and again beat off the murderous intruders and
pursued them to the furthest verge of the nest, that she succeeds
in her operation. When finished, she is still under the necessity
of closely guarding the cell, which the gluttonous workers would
otherwise tear open, and devour the eggs. This duty she performs for
six or eight hours with the vigilance of an Argus, at the end of
which time they lose their taste for this food, and will not touch it
even when presented to them. Here the labours of the mother cease,
and are succeeded by those of the workers. These know the precise
hour when the grubs have consumed their stock of food, and from
that time to their maturity regularly feed them with either honey or
pollen, introduced in their proboscis through a small hole in the
cover of the cell opened for the occasion and then carefully closed.
They are equally assiduous in another operation. As the grubs
increase in size the cell which contained them becomes too small,
and in their exertions to be more at ease they split its thin sides.
To fill up these breaches as fast as they occur with a patch of wax,
is the office of the workers, who are constantly on the watch to
discover when their services are wanted; and thus the cells daily
increase in size, in a way which to an observer ignorant of the
process seems very extraordinary.
The last duty of these affectionate foster-parents is to assist the
young bees in cutting open the cocoons which have inclosed them in
the state of _pupæ_. A previous labour however must not be omitted.
The workers adopt similar measures with the hive-bee for maintaining
the young pupæ concealed in these cocoons in a genial temperature. In
cold weather and at night they get upon them and impart the necessary
warmth by brooding over them in clusters. Connected with this part of
their domestic economy, M. P. Huber, a worthy scion of a celebrated
stock, and an inheritor of the science and merits of the great Huber
as well as of his name, in his excellent paper on these insects in
the sixth volume of the Linnean Transactions, from which most of
these facts are drawn, relates a singularly curious anecdote.
In the course of his ingenious and numerous experiments, M. Huber
put under a bell-glass about a dozen humble-bees without any store
of wax, along with a comb of about ten silken cocoons so unequal in
height that it was impossible the mass should stand firmly. Its
unsteadiness disquieted the humble-bees extremely. Their affection
for their young led them to mount upon the cocoons for the sake of
imparting warmth to the inclosed little ones, but in attempting
this the comb tottered so violently that the scheme was almost
impracticable. To remedy this inconvenience, and to make the comb
steady, they had recourse to a most ingenious expedient. Two or three
bees got upon the comb, stretched themselves over its edge, and with
their heads downwards fixed their fore feet on the table upon which
it stood, whilst with their hind feet they kept it from falling. In
this constrained and painful posture, fresh bees relieving their
comrades when weary, did these affectionate little insects support
the comb for nearly three days! At the end of this period they had
prepared a sufficiency of wax with which they built pillars that
kept it in a firm position: but by some accident afterwards these
got displaced, when they had again recourse to their former manœuvre
for supplying their place, and this operation they perseveringly
continued until M. Huber, pitying their hard case, relieved them by
fixing the object of their attention firmly on the table[702].
It is impossible not to be struck with the reflection that this most
singular fact is inexplicable on the supposition that insects are
impelled to their operations by a blind instinct alone. How could
mere machines have thus provided for a case which in a state of
nature has probably never occurred to ten nests of humble-bees since
the creation? If in this instance these little animals were not
guided by a process of reasoning, what is the distinction between
reason and instinct? How could the most profound architect have
better adapted the means to the end--how more dexterously _shored_ up
a tottering edifice, until his beams and his props were in readiness?
With respect to the operations of the _termites_ in rearing their
young I have not much to observe. All that is known is, that they
build commodious cells for their reception, into which the eggs of
the queen are conveyed by the workers as soon as laid, and where
when hatched they are assiduously fed by them until they are able to
provide for themselves.
In concluding this subject, it may not be superfluous to advert to
an objection which is sometimes thrown out against regarding with
any particular sympathy the affection of the lower animals to their
young, on the ground that this feeling is in them the result of
corporeal sensation only, and wholly different from that love which
human parents feel for their offspring. It is true that the latter
involves moral considerations which cannot have place in the brute
creation; but it would puzzle such objectors to explain in what
respect the affection which a mother feels for her new-born infant
the moment it has seen the light, differs from that of an insect
for its progeny. The affection of both is purely physical, and in
each case springs from sensations interwoven by the Creator in the
constitution of his creatures. If the parental love of the former
is worthy of our tenderest sympathies, that of the latter cannot be
undeserving of some portion of similar feeling.
I am, &c.
FOOTNOTES:
[658] P. 147, &c.
[659] Clark in _Linn. Trans._ iii. 304.
[660] Bonnet, ii. 344.
[661] The Rev. Dr. Sutton of Norwich made similar observations upon the
proceedings of this insect in his garden for two successive seasons.
[662] Rai. _Hist. Ins._ 254.
[663] Reaum. vi. 252.
[664] By this term I would distinguish the tribe of _Fossores_
of Latreille, which the French call _Wasp-Ichneumons_, and which
form the Linnean genus _Sphex_, divisible into several families as
_Sphecidæ_, _Pompilidæ_, _Bembecidæ_, &c.
[665] Mr. W. S. MacLeay in his very remarkable and learned work
(_Horæ Entomologicæ_) has very properly restored its name to the true
_Scarabæus_ of the ancients, which gives its name to this group.
[666] Mouffet, 153.
[667] J. Pierii Valeriani _Hieroglyphica_, 93-5. Mouffet, 156.
[668] _Travels_, ii. 306. Compare M. Latreille's learned Memoir
entitled _Des Insectes peints ou sculptes sur les Monumens antiques
de l'Egypte_. _Ann. du Mus._ 1819.
[669] Gleditsch _Physic. Bot. Oecon. Abhandl._ iii. 200-227.
[670] _Natural Theology_, 497.
[671] Latreille denominates this tribe _Securifera_; but as the tool
of these insects resembles a _saw_ and not a _hatchet_, we have
ventured to change it to _Serrifera_, which is more appropriate.
[672] Prof. Peck's _Nat. Hist. of the Slug-worm_, _t._ 12. _f._
12-14. PLATE XV. FIG. 21.
[673] _Linn. Trans._ iii. 23.
[674] _Apis._ **. _c._ 2. γ. K.
[675] PLATE XVI. FIG. 1.
[676] See Kirby in _Linn. Trans._ v. 254. _t._ 12. _f._ 15.
[677] See above, 150.
[678] Bonnet, ix. 398.
[679] liii. 37. _Pelopæus spirifex?_
[680] Reaum. vi. 269.
[681] De Geer, iii. 262.
[682] De Geer, iii. 548.
[683] Bonnet, ii. 435.
[684] De Geer, vii. 194.
[685] De Geer, vii. 268.
[686] Huber, 69.
[687] De Geer, ii. 1099.
[688] Gould, 37.
[689] Huber, 74.
[690] Huber, 78.
[691] The Russian shepherds ingeniously avail themselves of the
attachment of ants to their young, for obtaining with little trouble
a collection of the pupæ, which they sell as a dainty food for
nightingales. They scatter an ants' nest upon a dry plot of ground,
surrounded with a shallow trench of water, and place on one side
of it a few fir branches. Under these the ants, having no other
alternative, carefully arrange all their pupæ, and in an hour or
two the shepherd finds a large heap clean and ready for market.
Anderson's _Recreations in Agriculture, &c._ iv. 158.
[692] Huber, 83.
[693] Ibid. 93.
[694] p. 35.
[695] Huber, 110.
[696] Huber, 109.--Gould had, long before Huber, observed that female
ants cast their wings, pp. 59, 62, 64. I have frequently observed
them, sometimes with only one wing, at others with only fragments of
the wings; and again, at others they were so completely pulled off,
that it could not be known that they formerly had them, only by the
sockets in which they were inserted.
[697] Huber, 93.
[698] See Willughby in Rai. _Hist. Ins._ 251. and Reaum.
[699] Reaum. vi. 174.
[700] It is not unlikely that it may undergo some other alteration
in the bee's stomach, which may possibly secrete some peculiar
substance, as John Hunter discovered that the crop of the pigeon does.
[701] Dr. Johnson was ignorant of the etymology of this word. It is
clearly derived from the German _Hummel_ or _Hummel Biene_, a name
probably given it from its sound. Our English name would be more
significant were it altered to _Humming-bee_ or _Booming-bee_.
[702] _Linn. Trans._ vi. 247 &c.
LETTER XII.
_ON THE FOOD OF INSECTS._
Insects like other animals draw their _food_ from the vegetable and
animal kingdoms; but a very slight survey will suffice to show that
they enjoy a range over far more extensive territories.
To begin with the vegetable kingdom.--Of this vast field the larger
animals are confined to a comparatively small portion. Of the
thousands of plants which clothe the face of the earth, when we have
separated the grasses and a trifling number of herbs and shrubs,
the rest are disgusting to them, if not absolute poisons. But how
infinitely more plenteous is the feast to which Flora invites the
insect tribes! From the gigantic banyan which covers acres with its
shade, to the tiny fungus scarcely visible to the naked eye, the
vegetable creation is one vast banquet at which her insect guests
sit down. Perhaps not a single plant exists which does not afford a
delicious food to some insect, not excluding even those most nauseous
and poisonous to other animals--the acrid euphorbias, and the lurid
henbane and nightshade. Nor is it a presumptuous supposition that a
considerable proportion of these vegetables were created expressly
for their entertainment and support. The common nettle is of little
use either to mankind or the larger animals, but you will not doubt
its importance to the class of insects, when told that at least
thirty distinct species feed upon it. But this is not all. The larger
herbivorous animals are confined to a foliaceous or farinaceous diet.
They can subsist on no other part of a plant than its leaves and
seeds, either in a recent or dried state, with the addition sometimes
of the tender twigs or bark. Not so the insect race; to different
tribes of which every part of a plant supplies appropriate food. Some
attack its roots; others select the trunk and branches; a third class
feed upon the leaves; a fourth with yet more delicate appetite prefer
the flowers; and a fifth the fruit or seeds. Even still further
selection takes place. Of those which feed upon the roots, stem,
and branches, of vegetables, some larvæ eat only the bark (_Sesia
apiformis_, &c.), others the alburnum (_Semasia Wœberana_), others
the exuding resinous or other excretions (_Scoparia Resinella_), a
third class the pith (_Xanthia Ochraceago_), and a fourth penetrate
into the heart of the solid wood (_Prionus_, _Lamia_, _Cerambyx_,
&c.). Of those which prefer the leaves, some taste nothing but the
sap which fills their veins (_Aphides_ in all their states), others
eat only the parenchyma, never touching the cuticle (subcutaneous
_Tineæ_, _Gracillaria?_) others only the lower surface of the
leaf (many _Tortrices_), while a fourth description devour the
whole substance of the leaf (most _Lepidoptera_). And of the
flower-feeders, while some eat the very petals (_Cucullia Verbasci_,
_Xylina Linariæ_, &c.), others in their perfect state select the
pollen which swells the anthers (bees, _Lepturæ_, and _Mordellæ_),
and a still larger class of these the honey secreted in the nectaries
(most of the _Lepidoptera_, _Hymenoptera_, and _Diptera_).
Nor are insects confined to vegetables in their recent or
unmanufactured state. A beam of oak when it has supported the roof
of a castle five hundred years, is as much to the taste of some,
(_Anobia_,) as the same tree was in its growing state to that of
others; another class (_Ptini_) would sooner feast on the herbarium
of Brunfelsius, than on the greenest herbs that grow; and a third
(_Tineæ_, _Termites_), to whom
"... a river and a sea
Are a dish of tea,
And a kingdom bread and butter,"
would prefer the geographical treasures of Saxton or Speed, in spite
of their ink and alum, to the freshest rind of the flax plant.--The
larva of a little fly (_Oscinis cellaris_), whose economy, as I
can witness from my own observations, is admirably described by
Mentzelius[703], disdains to feed on any thing but wine or beer,
which like Boniface in the play it may be said both to eat and drink,
though, unlike its toping counterpart, indifferent to the age of its
liquor, which whether sweet or sour is equally acceptable.
A diversity of food almost as great may be boasted by the insects which
feed on animal substances. Some (flesh-flies, carrion-beetles, &c.)
devour dead carcases only, which they will not touch until imbued with
the _haut gout_ of putridity. Others, like Mr. Bruce's Abyssinians,
preferring their meat before it has passed through the hands of the
butcher, select it from living victims, and may with justice pride
themselves upon the peculiar freshness of their diet. Of these last,
different tribes follow different procedures. The Ichneumons devour
the flesh of the insects into which they have insinuated themselves.
Some of the Œstri, fixed in a spacious apartment beneath the skin of
an ox or deer, regale themselves on a purulent secretion with which
they are surrounded. Others of the same tribe, partial to a higher
temperature, attach themselves to the interior of the stomach of a
horse, and in a bath of chyme of 102 degrees of Fahrenheit revel
on its juices. The various species of horse-flies dart their sharp
lancets into the veins of quadrupeds, and satiate themselves in living
streams; while the gnat, the flea, the bug, and the louse, plunge their
proboscis even into those of us lords of the creation, and banquet
on "the ruddy drops which warm our hearts." Some make their repast
upon birds only, as the fly of the swallow, and other _Ornithomyiæ_,
and the bird-louse; insects nearly allied, though one is dipterous
and the other apterous. And a most singular animal belonging to the
latter tribe (_Nycteribia Vespertilionis_) revenges upon the bat its
ravages of the insect world[704]. Another numerous class kill their
prey outright, either devouring its solid parts, as the predaceous
and rove-beetles, &c., or imbibing its juices only, as the infinite
hordes of the field-bug tribe. And the larvæ of the gnat, chameleon
(_Stratyomis_), and other flies aquatic in that state, the leviathans
of the world of animalcules, swallow whole hosts of these minute
inhabitants of pools and ponds at a gulp, causing with their oral
apparatus a vortex in the water, down which myriads of victims are
incessantly hurried into their destructive maw.
But not only animals themselves, almost every animal substance that can
be named is the appropriate food of some insect. Multitudes find a
delicious nutriment in excrements of various kinds. Matters apparently
so indigestible as hair, wool, and leather, are the sole food of many
moths in the larva state (_Tinea tapetzella_, _pellionella_, &c.).
Even feathers are not rejected by others; and the grub of a beetle
(_Anthrenus Musæorum_), with powers of stomach which the dyspeptic
sufferer may envy, will live luxuriously upon horn[705].
For the most part, insects feeding upon animal substances will not
touch vegetables, and _vice versâ_. You must not however take the
rule without exceptions. Many caterpillars (as those of _Thyatira
derasa_, _Chariclea Delphinii_, &c.), though plants are their proper
food, will occasionally devour other caterpillars, and sometimes
even their own species. The large green grasshopper (_Acrida
viridissima_), and probably others of the order, will eat smaller
insects as well as its usual vegetable food[706]; so also will the
larvæ of many _Phryganeæ_. _Allantus marginellus_, as I was last
summer amused by witnessing, like many _Scatophagæ_, sips the nectar
of umbelliferous plants only till a fly comes within its reach,
pouncing upon which it gladly quits its vegetable for an animal
repast. _Anobium paniceum_, which ordinarily feeds upon wood, was,
as I before mentioned, once found by Mr. Sheppard in great abundance
living upon the dried Cantharides (_Cantharis vesicatoria_) of the
shops. On the other hand, _Necrophorus mortuorum_, which subsists on
carcases, and many other carnivorous species, will make a hearty meal
of a putrid fungus; _Ptinus Fur_ devours indifferently dried birds or
plants, not refusing even tobacco; and from the impossibility that
one of a million of the innumerable swarms of gnats which abound in
swampy places, particularly in regions which but for them would be
lost to sensitive existence, should ever taste blood, it seems clear
that they are usually contented with vegetable aliment. Indeed the
males, as well as those of the horse-fly of which even the females
readily imbibed the sugared fluid offered to them by Reaumur[707],
never suck blood at all; so that they must either feed on vegetable
matter, which in fact I have observed them to do, or fast during
their whole existence in the perfect state.