THE MASON-BEES
At a school where I once taught, one subject in particular appealed
to both master and pupils. This was open-air geometry, practical
surveying. When May came, once every week we left the gloomy schoolroom
for the fields. It was a regular holiday. We did our surveying on an
untilled plain, covered with flowering thyme and rounded pebbles. There
was room there for making every sort of triangle or polygon.
Well, from the very first day, my attention was attracted by something
suspicious. If I sent one of the boys to plant a stake, I would see him
stop frequently on his way, bend down, stand up again, look about and
stoop once more, neglecting his straight line and his signals. Another,
who was told to pick up the arrows, would forget and take up a pebble
instead; and a third, instead of measuring angles, would crumble a clod
of earth between his fingers.
[Illustration]
Most of them were caught licking a bit of straw. The surveying
suffered. What could the mystery be?
I inquired; and everything was explained. The scholars had known for a
long time what the master had not yet heard of, namely, that there was
a big black Bee who made clay nests on the pebbles in the fields. These
nests contained honey; and my surveyors used to open them and empty the
cells with a straw. The honey, although rather strong-flavored, was
most acceptable. I grew fond of it myself, and joined the nest-hunters,
putting off the lesson until later. It was thus that I first made the
acquaintance of the Mason-bee.
The Bee herself is a magnificent insect, with dark-violet wings and a
black-velvet dress. We have two kinds of Mason-bees in our district:
this one, who builds by herself on walls or pebbles, and the Sicilian
Mason-bee, who builds in colonies under sheds and roofs. Both use the
same kind of material: hard clay, mixed with a little sand and kneaded
into a paste with the Bee’s own saliva, forming, when dry, a sort of
hard cement.
Man’s masonry is formed of stones laid one above the other and cemented
together with lime. The Mason-bee’s work can bear comparison with
ours. Instead of stones, she uses big pieces of gravel. She chooses
them carefully one by one, picks out the hardest bits, generally with
corners, which, fitting one into the other, make a solid whole. She
holds them together with layers of her mortar, sparingly applied. Thus
the outside of her cell looks like a rough stone house; but the inside,
which must be smooth in order not to hurt the Bee-baby’s tender skin,
is covered with a coat of pure mortar. This inner whitewash, however,
is not put on artistically, but in great splashes; and the grub takes
care, after it has finished eating its honey, to make itself a cocoon
and hang the walls of its room with silk.
When the cell is finished, the Bee at once sets to work to provide food
for it. The flowers round about, especially those of the yellow broom,
which in May deck the pebbly borders of the mountain streams with gold,
supply her with sugary liquid and pollen. She comes with her crop
swollen with honey and her body yellowed underneath with pollen-dust.
She dives headfirst into the cell; and for a few moments you see her
jerk violently as she empties her crop of the honey-sirup. Afterwards,
she comes out of the cell, only to go in again at once, but this time
backwards. The Bee now brushes the lower side of her abdomen with her
two hind-legs and rids herself of her load of pollen. Once more she
comes out and once more goes in headfirst. It is a question of stirring
the materials, with her jaws for a spoon, and making the whole into a
smooth mixture. She does not do this after every journey; only once in
a while, when she has gathered a good deal of food.
When the cell is half full of food, she thinks there is enough. An egg
must now be laid on top of the paste and the house must be closed. All
this is done quickly. The cover is a lid of pure mortar, which the Bee
builds by degrees, working from the outside to the center. Two days at
most appeared to me to be enough for everything, provided that no bad
weather—rain or merely clouds—came to interrupt the work. Then a second
cell is built, with its back to the first and provisioned in the same
manner. A third, a fourth, and so on follow, each supplied with honey
and an egg and closed before the foundations of the next are laid.
[Illustration: “The flowers which deck the mountain streams with gold
supply her with sugary liquid and pollen.”]
When all the cells are finished, the Bee builds a thick cover over the
group, to protect her grub-babies from damp, heat and cold. This cover
is made of the usual mortar, but on this occasion with no small stones
in it. The Bee applies it pellet by pellet, trowelful by trowelful, to
the depth of about a third of an inch over the cluster of cells, which
disappear entirely under the clay covering. When this is done, the nest
has the shape of a rough dome, equal in size to half an orange. One
would take it for a round lump of mud which had been thrown and half
crushed against a stone and had then dried where it was. This outer
covering dries as quickly as the cement we use in our houses; and the
nest is soon almost as hard as a stone.
Instead of building a brand-new nest on a hitherto unoccupied bowlder,
the Mason-bee of the Walls is always glad to make use of old nests
built the year before. These need only a little repair to put them
in good condition. The Bee who has chosen one of these nests looks
about to see what parts need repairing, tears off the strips of cocoon
hanging from the walls, removes the fragments of clay that fell from
the ceiling when the young Bee of the preceding year bored her way
through it, gives a coat of mortar to parts that need it, mends the
opening a little, and that is all. She then goes about storing honey
and laying her egg, as she would in a new cell. When all the cells, one
after the other, are thus furnished, the Bee puts a few touches on the
outer dome of cement, if it needs them; and she is through.
From one and the same nest there come out several inhabitants, brothers
and sisters, the males with a bright brick-red fleece, and the female
of a splendid velvety black, with dark-violet wings. They are all the
children of the Bee who built or repaired and furnished the cells. The
male Bees lead a careless existence, never work, and do not return to
the clay houses except for a brief moment to woo the ladies; they have
nothing to do with the housekeeping or the new nests. What they want is
the nectar in the flower-cups, not mortar to build with. There are left
the sisters, who will be the mothers of the next family. As sisters,
they all have equal rights to the nest. They do not go by this rule,
however. The nest belongs to the one who first takes possession of it.
If any of the others or any neighbors dispute her ownership, she fights
them until they have the worst of it and fly away, leaving her in peace.
AN ENEMY OF THE MASON-BEE
All is not smooth sailing after the Mason-bee has finished building
her dome of cells. It is then that a certain Stelis-wasp, much smaller
than the Mason-bee, appears, looks carefully at the outside of the
Mason-bee’s home, and makes up her mind, weak and small as she is,
to introduce her eggs into this cement fortress. Everything is most
carefully closed: a layer of rough plaster, at least two fifths of an
inch thick, entirely covers the cells, which are each of them sealed
with a thick mortar plug. The plaster is almost as hard as a rock.
Never mind! The little insect is going to reach the honey in those
cells.
She pluckily sets to. Atom by atom, she drives a hole in the plaster
and scoops out a shaft just large enough to let her through; she
reaches the lid of the cell and gnaws it till she catches sight of the
honey. It is a slow and painful process, in which the feeble Wasp wears
herself out. I find it hard to break the plaster with the point of my
knife. How much harder, then, for the insect, with her tiny pincers!
When she reaches the honey, the Stelis-wasp slips through and, on the
surface of the provisions, side by side with the Mason-bee’s, she lays
a number of her own eggs. The honey-food will be the common property
of all the new arrivals, the Stelis-wasp’s grubs as well as the
Mason-bee’s.
The next thing for the parasite Wasp to do is to wall up the opening
she has made, so that other robbers cannot get in. At the foot of the
nest, the Wasp collects a little red earth; she makes it into mortar by
wetting it with saliva; and with the pellets thus prepared she fills up
the entrance shaft as neatly as if she were a master-mason. The mortar,
being red, shows up against the Bee’s house, which is white; so when we
see the red speck on the pale background of the Bee’s nest we know a
Stelis-wasp has been that way.
As a result of the Stelis’ action, the poor Bee-baby will starve to
death. The Wasp’s grubs mature first and eat up all the food.
[Illustration]
THE BEE HERSELF TURNED BURGLAR
Sometimes, when a Mason-bee has stayed too long among the flowers,
getting honey for her cell, she finds the cell closed when she returns
home. A neighbor Bee has taken the opportunity to lay her eggs there,
after finishing the building and stocking it with provisions. The real
Bee-owner is shut out.
She does not hesitate long about what to do. After she has examined
her former home very carefully, to make sure it is closed against her,
she seems to say to herself, “An egg for an egg, a cell for a cell.
You’ve stolen my house; I’ll steal yours.” She goes to another Bee’s
dwelling and patiently gnaws the mortar lid or door. When she has made
an opening, she stands bending over the cell, her head half-buried in
it, as if thinking. She goes away, she returns undecidedly; at last she
makes up her mind. The other Bees, meanwhile, pay no attention to her,
not even the one who laid the egg in the cell.
[Illustration]
The Bee who has turned burglar snaps up the strange egg from the
surface of the honey and flings it on the rubbish-heap as carelessly as
if she were ridding the house of a bit of dirt. Then, although there is
already plenty of honey in the cell, she adds more from her own stock,
lays her own egg, and closes up the house again. The lid is repaired
to look like new and everything restored to order. The Bee has had her
revenge; her anger is appeased. Next time she lays an egg it will be in
her own cell, unless that has again been seized by another.
SOME USEFUL VISITORS OF THE BEES
I have told you about the robber Stelis-wasp who enters the Bee’s
cement house and steals the provisions laid up for the Bee-baby; she is
not the only one who despoils the poor Mason-bee. There is another Bee,
the Dioxys, who acts in about the same way as the Stelis-wasp, except
that she sometimes does even worse, and eats up the grub itself, as
well as its honey. Then there are the Osmia-bees and the Leaf-cutting
Bees, who make themselves very much at home in the Bees’ houses, when
they get a chance, keeping out the real owners; and there are also
three flies, whose grubs eat the Bee-grub alive! It sometimes seems
wonderful that the Mason-bee should ever live to grow up; and you
will be glad to hear of three other visitors the Bee-grub has, which
actually help instead of making it impossible for it to live. These are
three Beetles.
The old nests which the Mason-bees build in, to save themselves the
trouble of making new ones, are often in a very insanitary condition.
The cells are full of dead larvæ (larva is another word for grub, and
both words mean the first stage of the insect after leaving the egg,
when it looks like a little worm), which, for some reason or other,
could not break through their hard prisons; of honey which has not been
eaten and has turned sour; of tattered cocoons, and shreds of skin,
left behind when the grubs turned into Bees. All these dead and useless
things are, of course, not pleasant to have in any house, especially in
a tidy Bee’s.
Here is where the Beetles come to the rescue. They enter the Bee’s
house and lay their eggs there. The larvæ, when they come out of the
eggs, begin to make themselves useful. Two species of larvæ gnaw the
remains of the dead Bees; the third, which is quite a good-looking
worm, with a black head and the rest of its body a pretty pink, takes
care of the spoiled honey. This worm turns into a Beetle in a red dress
with blue ornaments, whom you may often see strolling about the Bee’s
house in the working season, tasting here and there drops of honey
oozing from some cracked cell. The Bees leave him in peace, as if they
knew that it was his duty to keep their house wholesome.
Still later, when the Bee’s house, exposed as it is to wind and
weather, cracks and falls to pieces almost entirely, the Bees leave
it for good and all, and still other insects take possession of it.
These are gypsies, who are not particular where they camp out. Spiders
make their homes in the blind alleys which used to be cells, and weave
white-satin screens, behind which they lie in wait for passing game.
The Hunting-wasps arrange nooks with earthen embankments or clay
partitions, and there store up small members of the Spider tribe as
food for their families. So we see that the house that the Mason-bee
built for herself is useful to many others, good, bad, or indifferent
friends of hers as the case may be.
[Illustration]