A MASON-WASP
I
HER CHOICE OF A BUILDING-SITE
Of the various insects that like to make their home in our houses,
certainly the most interesting, for her beautiful shape, her curious
manners, and her wonderful nest, is a certain Wasp called the Pelopæus.
She is very little known, even to the people by whose fireside she
lives. This is owing to her quiet, peaceful ways; she is so very
retiring that her host is nearly always ignorant of her presence. It is
easy for noisy, tiresome, unpleasant persons to make themselves famous.
I will try to rescue this modest creature from her obscurity.
The Pelopæus is an extremely chilly mortal. She pitches her tent under
the kindly sun that ripens the olive and prompts the Cicada’s song; and
even then she needs for her family the additional warmth to be found in
our dwellings. Her usual refuge is the peasant’s lonely cottage, with
its old fig-tree shading the well in front of the door. She chooses one
exposed to all the heat of summers, and if possible possessing a big
fireplace in which a fire of sticks always burns. The cheerful blaze on
winter evenings has a great influence upon her choice, for she knows by
the blackness of the chimney that the spot is a likely one. A chimney
that is not well glazed by smoke gives her no confidence: people must
shiver with cold in that house.
During the dog-days in July and August the visitor suddenly appears,
seeking a place for her nest. She is not in the least disturbed by the
bustle and movement of the household: they take no notice of her nor
she of them. She examines—now with her sharp eyes, now with her
sensitive antennæ—the corners of the blackened ceiling, the rafters,
the chimney-piece, the sides of the fireplace especially, and even the
inside of the flue. Having finished her inspection and duly approved of
the site she flies away, soon to return with the pellet of mud which
will form the first layer of the building.
The spot she chooses varies greatly, and often it is a very curious
one. The temperature of a furnace appears to suit the young Pelopæus:
at least the favourite site is the chimney, on either side of the flue,
up to a height of twenty inches or so. This snug shelter has its
drawbacks. The smoke gets to the nests, and gives them a glaze of brown
or black like that which covers the stonework. They might easily be
taken for inequalities in the mortar. This is not a serious matter,
provided that the flames do not lick against the nests. That would stew
the young Wasps to death in their clay pots. But the mother Wasps seems
to understand this: she only places her family in chimneys that are too
wide for anything but smoke to reach their sides.
But in spite of all her caution one danger remains. It sometimes
happens, while the Wasp is building, that the approach to the
half-built dwelling is barred to her for a time, or even for the whole
day, by a curtain of steam or smoke. Washing-days are most risky. From
morning till night the housewife keeps the huge cauldron boiling. The
smoke from the hearth, the steam from the cauldron and the wash-tub,
form a dense mist in front of the fireplace.
It is told of the Water-Ouzel that, to get back to his nest, he will
fly through the cataract under a mill-weir. This Wasp is even more
daring: with her pellet of mud in her teeth she crosses the cloud of
smoke and disappears behind it, where she becomes invisible, so thick
is the screen. An irregular chirring sound, the song she sings at her
work, alone betrays her presence. The building goes on mysteriously
behind the cloud. The song ceases, and the Wasp flies back through the
steam, quite unharmed. She will face this danger repeatedly all day,
until the cell is built, stored with food, and closed.
Once and once only I was able to observe a Pelopæus at my own fireside;
and, as it happened, it was a washing-day. I had not long been
appointed to the Avignon grammar-school. It was close upon two o’clock,
and in a few minutes the roll of the drum would summon me to give a
scientific lecture to an audience of wool-gatherers. Suddenly I saw a
strange, agile insect dart through the steam that rose from the
wash-tub. The front part of its body was very thin, and the back part
was very plump, and the two parts were joined together by a long
thread. It was the Pelopæus, the first I had seen with observant eyes.
Being very anxious to become better acquainted with my visitor, I
fervently entreated the household not to disturb her in my absence.
Things went better than I dared hope. On my return she was still
carrying on her mason’s work behind the steam. Being eager to see the
building of the cells, the nature of the provisions, and the evolution
of the young Wasps, I raked the fire so as to decrease the volume of
smoke, and for a good two hours I watched the mother Wasp diving
through the cloud.
Never again, in the forty years that followed, was my fireplace
honoured with such a visit. All the further information I have gathered
was gleaned on the hearths of my neighbours.
The Pelopæus, it appears, is of a solitary and vagrant disposition. She
nearly always builds a lonely nest, and unlike many Wasps and Bees, she
seldom founds her family at the spot where she was reared herself. She
is often found in our southern towns, but on the whole she prefers the
peasant’s smoky house to the townsman’s white villa. Nowhere have I
seen her so plentiful as in my village, with its tumble-down cottages
burnt yellow by the sun.
It is obvious that this Wasp, when she so often chooses the chimney as
her abode, is not seeking her own comfort: the site means work, and
dangerous work. She seeks the welfare of her family. This family, then,
must require a high temperature, such as other Wasps and Bees do not
need.
I have seen a Pelopæus nest in the engine-room of a silk-factory, fixed
to the ceiling just above the huge boiler. At this spot the thermometer
marked 120 degrees all through the year, except at night and on
holidays.
In a country distillery I have found many nests, fixed on anything that
came to hand, even a pile of account-books. The temperature of one of
these, quite close to the still, was 113 degrees. It is plain that this
Wasp cheerfully endures a degree of heat that makes the oily palm-tree
sprout.
A boiler or a furnace she regards as the ideal home, but she is quite
willing to content herself in any snug corner: a conservatory, a
kitchen-ceiling, the recess of a closed window, the wall of a cottage
bedroom. As to the foundation on which she fixes her nest, she is
entirely indifferent. As a rule she builds her groups of cells on
stonework or timber; but at various times I have seen nests inside a
gourd, in a fur cap, in the hollow of a brick, on the side of a bag of
oats, and in a piece of lead tubing.
Once I saw something more remarkable still, in a farm near Avignon. In
a large room with a very wide fireplace the soup for the farm-hands and
the food for the cattle simmered in a row of pots. The labourers used
to come in from the fields to this room, and devour their meal with the
silent haste that comes from a keen appetite. To enjoy this half-hour
comfortably they would take off their hats and smocks, and hang them on
pegs. Short though this meal was, it was long enough to allow the Wasps
to take possession of their garments. The inside of a straw hat was
recognised as a most useful building-site, the folds of a smock were
looked upon as a capital shelter; and the work of building started at
once. On rising from the table one of the men would shake his smock,
and another his hat, to rid it of the Wasp’s nest, which was already
the size of an acorn.
The cook in that farmhouse regarded the Wasps with no friendly eye.
They dirtied everything, she said. Dabs of mud on the ceiling, on the
walls, or on the chimney-piece you could put up with; but it was a very
different matter when you found them on the linen and the curtains. She
had to beat the curtains every day with a bamboo. And it was trouble
thrown away. The next morning the Wasps began building as busily as
ever.
II
HER BUILDING
I sympathised with the sorrows of that farm-cook, but greatly regretted
that I could not take her place. How gladly I would have left the Wasps
undisturbed, even if they had covered all the furniture with mud! How I
longed to know what the fate of a nest would be, if perched on the
uncertain support of a coat or a curtain! The nest of the Mason-bee is
made of hard mortar, which surrounds the twig on which it is built, and
becomes firmly fixed to it; but the nest of the Pelopæus Wasp is a mere
blob of mud, without cement or foundations.
The materials of which it is made are nothing but wet earth or dirt,
picked up wherever the soil is damp enough. The thin clay of a
river-bank is very suitable, but in my stony country streams are rare.
I can, however, watch the builders at my leisure in my own garden, when
a thin trickle of water runs all day, as it does sometimes, through the
little trenches that are cut in my vegetable plots.
The Pelopæus Wasps of the neighbourhood soon become aware of this glad
event, and come hurrying up to take advantage of the precious layer of
mud, a rare discovery in the dry season. They scrape and skim the
gleaming, shiny surface with their mandibles while standing high on
their legs, with their wings quivering and their black bodies upraised.
No neat little housewife, with skirts carefully tucked up out of the
dirt, could be more skilful in tackling a job likely to soil her
clothes. These mud-gatherers have not an atom of dirt upon them, so
careful are they to tuck up their skirts in their own fashion, that is
to say, to keep their whole body out of the way, all but the tips of
their legs and the busy points of the mandibles with which they work.
In this way a dab of mud is collected, almost the size of a pea. Taking
the load in its teeth the insect flies off, adds a layer to its
building, and soon returns to collect another pellet. The same method
is pursued as long as the earth remains sufficiently wet, during the
hottest hours of the day.
But the favourite spot is the great fountain in the village, where the
people come to water their mules. Here there is a constant sheet of
black mud which neither the hottest sunshine nor the strongest wind can
dry. This bed of mire is very unpleasant for the passers-by, but the
Pelopæus loves to gather her pellets here, amid the hoofs of the mules.
Unlike some builders in clay, such as the Mason-bees, the Wasp does not
improve the mud to make it into mortar, but uses it just as it is.
Consequently her nests are flimsy work, absolutely unfitted to stand
the changes and chances of the open air. A drop of water laid upon
their surface softens the spot touched and reduces it to mud again,
while a sprinkling equal to an average shower turns it to pap. They are
nothing but dried slime, and become slime again as soon as they are
wetted.
It is plain, then, that even if the young Pelopæus were not so chilly
by nature, a shelter is indispensable for the nests, which would go to
pieces at the first shower of rain. That is why this Wasp is so fond of
human dwellings, and especially of the chimney.
Before receiving its final coating, which covers up the details of the
building, the nest has a certain beauty of its own. It consists of a
cluster of cells, sometimes arranged side by side in a row—which makes
it look rather like a mouth-organ—but more often grouped in layers
placed one above the other. I have sometimes counted as many as fifteen
cells; some nests contain only ten; others are reduced to three or
four, or even only one.
In shape the cells are not far from cylinders, slightly larger at the
mouth than at the base. They are a little more than an inch long, and
about half an inch wide. Their delicate surface is carefully polished,
and shows a series of string-like projections, running cross-wise, not
unlike the twisted cords of some kinds of gold-lace. Each of these
strings is a layer of the building; it comes from the clod of mud used
for the coping of the part already built. By counting them you can tell
how many journeys the Wasp has made in the course of her work. There
are usually between fifteen and twenty. For one cell, therefore, the
industrious builder fetches materials something like twenty times.
The mouth of the cells is, of course, always turned upwards. A pot
cannot hold its contents if it be upside down. And the Wasp’s cell is
nothing but a pot intended to hold the store of food, a pile of small
Spiders.
The cells—built one by one, stuffed full of Spiders, and closed as the
eggs are laid—preserve their pretty appearance until the cluster is
considered large enough. Then, to strengthen her work, the Wasp covers
the whole with a casing, as a protection and defence. She lays on the
plaster without stint and without art, giving it none of the delicate
finishing-touches which she lavishes on the cells. The mud is applied
just as it is brought, and merely spread with a few careless strokes.
The beauties of the building all disappear under this ugly husk. In
this final state the nest is like a great splash of mud, flung against
the wall by accident.
III
HER PROVISIONS
Now that we know what the provision-jar is like, we must find out what
it contains.
The young Pelopæus is fed on Spiders. The food does not lack variety,
even in the same nest and the same cell, for any Spider may form a
meal, as long as it is not too large for the jar. The Cross Spider,
with three crosses of white dots on her back, is the dish that occurs
oftenest. I think the reason for this is simply that the Wasp does not
go far from home in her hunting-trips, and the Spider with the crosses
is the easiest to find.
The Spider, armed with poison-fangs, is a dangerous prey to tackle.
When of fair size, she could only be conquered by a greater amount of
daring and skill than the Wasp possesses. Moreover, the cells are too
small to hold a bulky object. The Wasp, therefore, hunts game of
moderate size. If she meets with a kind of Spider that is apt to become
plump, she always chooses a young one. But, though all are small, the
size of her victims varies enormously, and this variation in size leads
also to variation in number. One cell will contain a dozen Spiders,
while in another there are only five or six.
Another reason for her choice of small Spiders is that she kills them
before potting them in her cells. She falls suddenly upon her prey, and
carries it off almost without pausing in her flight. The skilful
paralysis practised by some insects is unknown to her. This means that
when the food is stored it soon decays. Fortunately the Spiders are
small enough to be finished at a single meal. If they were large and
could only be nibbled here and there, they would decay, and poison the
grubs in the nest.
I always find the egg, not on the surface of the heap, but on the first
Spider that was stored. There is no exception to this rule. The Wasp
places a Spider at the bottom of the cell, lays her egg upon it, and
then piles the other Spiders on the top. By this clever plan the grub
is obliged to begin on the oldest of the dead Spiders, and then go on
to the more recent. It always finds in front of it food that has not
had time to decompose.
The egg is always laid on the same part of the Spider, the end
containing the head being placed on the plumpest spot. This is very
pleasant for the grub, for the moment it is hatched it can begin eating
the tenderest and nicest food in the store. Not a mouthful is wasted,
however, by these economical creatures. When the meal is finished there
is practically nothing left of the whole heap of Spiders. This life of
gluttony lasts for eight or ten days.
The grub then sets to work to spin its cocoon, a sack of pure,
perfectly white silk, extremely delicate. Something more is required to
make this sack tough enough to be a protection, so the grub produces
from its body a sort of liquid varnish. As soon as it trickles into the
meshes of the silk this varnish hardens, and becomes a lacquer of
exquisite daintiness. The grub then fixes a hard plug at the base of
the cocoon to make all secure.
When finished, the work is amber-yellow, and rather reminds one of the
outer skin of an onion. It has the same fine texture, the same colour
and transparency; and like the onion skin it rustles when it is
fingered. From it, sooner or later according to temperature, the
perfect insect is hatched.
It is possible, while the Wasp is storing her cell, to play her a trick
which will show how purely mechanical her instincts are. A cell has
just been completed, let us suppose, and the huntress arrives with her
first Spider. She stores it away, and at once fastens her egg on the
plumpest part of its body. She sets out on a second trip. I take
advantage of her absence to remove with my tweezers from the bottom of
the cell both the dead Spider and the egg.
The disappearance of the egg must be discovered by the Wasp, one would
think, if she possesses the least gleam of intelligence. The egg is
small, it is true, but it lies on a comparatively large object, the
Spider. What will the Wasp do when she finds the cell empty? Will she
act sensibly, and repair her loss by laying a second egg? Not at all;
she behaves most absurdly.
What she does is to bring a second Spider, which she stores away with
as much cheerful zeal as if nothing unfortunate had occurred. She
brings a third and a fourth, and still others, each of whom I remove
during her absence; so that every time she returns from the chase the
storeroom is found empty. I have seen her persist obstinately for two
days in seeking to fill the insatiable jar, while my patience in
emptying it was equally unflagging. With the twentieth victim—possibly
owing to the fatigue of so many journeys—the huntress considered that
the pot was sufficiently supplied, and began most carefully to close
the cell that contained absolutely nothing.
The intelligence of insects is limited everywhere in this way. The
accidental difficulty which one insect is powerless to overcome, any
other, no matter what its species, will be equally unable to cope with.
I could give a host of similar examples to show that insects are
absolutely without reasoning power, notwithstanding the wonderful
perfection of their work. A long series of experiments has forced me to
conclude that they are neither free nor conscious in their industry.
They build, weave, hunt, stab, and paralyse their prey, in the same way
as they digest their food, or secrete the poison of their sting,
without the least understanding of the means or the end. They are, I am
convinced, completely ignorant of their own wonderful talents.
Their instinct cannot be changed. Experience does not teach it; time
does not awaken a glimmer in its unconsciousness. Pure instinct, if it
stood alone, would leave the insect powerless in the face of
circumstances. Yet circumstances are always changing, the unexpected is
always happening. In this confusion some power is needed by the
insect—as by every other creature—to teach it what to accept and what
to refuse. It requires a guide of some kind, and this guide it
certainly possesses. Intelligence is too fine a word for it: I will
call it discernment.
Is the insect conscious of what it does? Yes, and no. No, if its action
is guided by instinct. Yes, if its action is the result of discernment.
The Pelopæus, for instance, builds her cells with earth already
softened into mud. This is instinct. She has always built in this way.
Neither the passing ages nor the struggle for life will induce her to
imitate the Mason-bee and make her nest of dry dust and cement.
This mud nest of hers needs a shelter against the rain. A hiding-place
under a stone, perhaps, sufficed at first. But when she found something
better she took possession of it. She installed herself in the home of
man. This is discernment.
She supplies her young with food in the form of Spiders. This is
instinct, and nothing will ever persuade her that young Crickets are
just as good. But should there be a lack of her favourite Cross Spider
she will not leave her grubs unfed; she will bring them other Spiders.
This is discernment.
In this quality of discernment lies the possibility of future
improvement for the insect.
IV
HER ORIGIN
The Pelopæus sets us another problem. She seeks the warmth of our
fireplaces. Her nest, built of soft mud which would be reduced to pulp
by damp, must have a dry shelter. Heat is a necessity to her.
Is it possible that she is a foreigner? Did she come, perhaps, from the
shores of Africa, from the land of dates to the land of olives? It
would be natural, in that case, that she should find our sunshine not
warm enough for her, and should seek the artificial warmth of the
fireside. This would explain her habits, so unlike those of the other
Wasps, by all of whom mankind is avoided.
What was her life before she became our guest? Where did she lodge
before there were any houses? Where did she shelter her grubs before
chimneys were thought of?
Perhaps, when the early inhabitants of the hills near Sérignan were
making weapons out of flints, scraping goatskins for clothes, and
building huts of mud and branches, those huts were already frequented
by the Pelopæus. Perhaps she built her nest in some bulging pot, shaped
out of clay by the thumbs of our ancestors; or in the folds of the
garments, the skins of the Wolf and the Bear. When she made her home on
the rough walls of branches and clay, did she choose the nearest spot,
I wonder, to the hole in the roof by which the smoke was let out?
Though not equal to our chimneys it may have served at a pinch.
If the Pelopæus really lived here with the earliest human inhabitants,
what improvements she has seen! She too must have profited greatly by
civilisation: she has turned man’s increasing comfort into her own.
When the dwelling with a roof and a ceiling was planned, and the
chimney with a flue was invented, we can imagine the chilly creature
saying to herself:
“How pleasant this is! Let us pitch our tent here.”
But we will go back further still. Before huts existed, before the
niche in the rut, before man himself had appeared, where did the
Pelopæus build? The question does not stand alone. Where did the
Swallow and the Sparrow build before there were windows and chimneys to
build in?
Since the Swallow, the Sparrow, and the Wasp existed before man, their
industry cannot be dependent on the works of man. Each of them must
have had an art of building in the time when man was not here.
For thirty years and more I asked myself where the Pelopæus lived in
those times. Outside our houses I could find no trace of her nests. At
last chance, which favours the persevering, came to my help.
The Sérignan quarries are full of broken stones, of refuse that has
been piled there in the course of centuries. Here the Fieldmouse
crunches his olive-stones and acorns, or now and then a Snail. The
empty Snail-shells lie here and there beneath a stone, and within them
different Bees and Wasps build their cells. In searching for these
treasures I found, three times, the nest of a Pelopæus among the broken
stones.
These three nests were exactly the same as those found in our houses.
The material was mud, as always; the protective covering was the same
mud. The dangers of the site had suggested no improvements to the
builder. We see, then, that sometimes, but very rarely, the Pelopæus
builds in stoneheaps and under flat blocks of stone that do not touch
the ground. It was in such places as these that she must have made her
nest before she invaded our houses.
The three nests, however, were in a piteous state. The damp and
exposure had ruined them, and the cocoons were in pieces. Unprotected
by their earthen cover the grubs had perished—eaten by a Fieldmouse or
another.
The sight of these ruins made me wonder if my neighbourhood were really
a suitable place for the Pelopæus to build her nest out of doors. It is
plain that the mother Wasp dislikes doing so, and is hardly ever driven
to such a desperate measure. And if the climate makes it impossible for
her to practise the industry of her forefathers successfully, I think
we may conclude that she is a foreigner. Surely she comes from a hotter
and drier climate, where there is little rain and no snow.
I believe the Pelopæus is of African origin. Far back in the past she
came to us through Spain and Italy, and she hardly ever goes further
north than the olive-trees. She is an African who has become a
naturalised Provençal. In Africa she is said often to nest under
stones, but in the Malay Archipelago we hear of her kinswoman in
houses. From one end of the world to the other she has the same
tastes—Spiders, mud cells, and the shelter of a man’s roof. If I were
in the Malay Archipelago I should turn over the stone-heaps, and should
most likely discover a nest in the original position, under a flat
stone.