The trap-door spider has furnished me with one of the most interesting
bits of natural history I have found on the coast. An obliging sojourner
near me from one of the Eastern States had discovered a large plot of
uncultivated ground above the beach that abounded in the hidden burrows
of these curious animals. One afternoon he volunteered to conduct me to
the place.
The ground was scantily covered with low bushy and weedy growths. My
guide warned me that the quarry we sought was hard to find. I, indeed,
found it so. It not only required an "eye as practiced as a blind man's
touch," it required an eye practiced in this particular kind of
detective work. My new friend conducted me down into the plot of ground
and, stopping on the edge of it, said, "There is a nest within two feet
of me." I fell to scrutinizing the ground as closely as I knew how,
fairly bearing on with my eyes; I went over the soil inch by inch with
my eyes, but to no purpose. There was no mark on the gray and brown
earth at my feet that suggested a trap-door, or any other device. I
stooped low, but without avail. Then my guide stooped, and with a long
needle pried up a semicircular or almost circular bit of the gray soil
nearly the size of a silver quarter of a dollar, which hinged on the
straight side of it, and behold--the entrance to the spider's castle! I
was not prepared for anything so novel and artistic--a long silken
chamber, about three quarters of an inch in diameter, concealed by a
silken trap-door, an inch in its greatest diameter. The under side of
the door, a dull white, the color of old ivory, is slightly convex, and
its top is a brownish gray to harmonize with its surroundings, and
slightly concave. Its edges are beveled so that it fits into the flaring
or beveled end of the chamber with the utmost nicety. No joiner could
have done it better. A faint semicircular raised line of clay as fine as
a hair gave the only clue. The whole effect, when the door was held
open, was of a pleasing secret suddenly revealed.
Then we walked about the place, and, knowing exactly what to look for, I
gave my eyes another chance, but they were slow to profit by it. My
guide detected one after another, and when I failed, he would point them
put to me. But presently I caught on, as they say, and began to find
them unaided.
We often found the lord of the manor on duty as doorkeeper, and in no
mood to see strangers. He held his door down by inserting his fangs in
two fine holes near the edge and bracing himself, or, rather, herself
(as, of course, it is the female), offered a degree of resistance
surprising in an insect. If one persists with a needle, there is often
danger of breaking the door. But when one has made a crack wide enough
to allow one to see the spider, she lets go her hold and rushes farther
down in her burrow.
Occasionally we found one about half the usual size, indicating a young
spider, but no other sizes. My guide said they only emerge from their
tunnel at night, and proved it by an ingenious mechanical device made of
straws attached to the door. When the door was opened, the straws lifted
up, but did not fall down when it was closed. Whenever he found the
straw still up in the morning he knew the door had been opened in the
night.
As they are nocturnal in habits, they doubtless prey upon other insects,
such as sow-bugs and crickets, which the night brings forth. Two bright
specks upon the top of the head appear to be eyes, but they are so small
they probably only serve to enable them to tell night from day. I think
these spiders are mainly guided by a marvelously acute tactile sense.
They probably feel the slightest vibration in the earth or air, unless
they have a sixth sense of which we know nothing.
All their work, the building and repairing of their nests, as well as
all their hunting, is done by night. This habit, in connection with
their extreme shyness, makes the task of getting at their life-histories
a difficult one. The inside of the burrow seems coated with a finer and
harder substance than the soil in which they are dug. It is made on the
spot, the spider mixing some secretion of her own with the clay, and
working it up into a finer product.
The trap-door sooner or later wears out at the hinge, and is then
discarded and a new door manufactured. We saw many nests with the old
door lying near the entrance. The door is made of several layers of silk
and clay, and is a substantial affair.
The spider families all have the gift of genius. Of what ingenious
devices and arts are they masters! How wide their range! They spin, they
delve, they jump, they fly. They are the original spinners. They have
probably been on their job since carboniferous times, many millions of
years before man took up the art. And they can spin a thread so fine
that science makes the astonishing statement that it would take four
millions of them to make a thread the caliber of one of the hairs of our
head--a degree of delicacy to which man can never hope to attain.
Trap-doors usually mean surprises and stratagems, secrets and betrayals,
and this species of the arachnids is proficient in all these things.
The adobe soil on the Pacific coast is as well fitted to the purposes of
this spider as if it had been made for her special use. But, as in all
such cases, the soil was not made for her, but she is adapted to it. It
is radically unlike any soil on the Atlantic coast--the soil for cañons
and the rectangular watercourses, and for the trap-door spider. It is a
tough, fine-grained homogeneous soil, and when dry does not crumble or
disintegrate; the cohesion of particles is such that sun-dried brick are
easily made from it.
This spider is found in New Mexico, Arizona, California, and Jamaica. It
belongs to the family of _Mygalidae_. It resembles in appearance the
tarantula of Europe, described by Fabre, and has many of the same
habits; but its habitation is a much more ingenious and artistic piece
of workmanship than that of its European relative. The tarantula has no
door to her burrow, but instead she builds about the entrance a kind of
breastwork an inch high and nearly two inches in diameter, and from this
fortress sallies out upon her prey. She sinks a deeper shaft than does
our spider, but excavates it in the same way with similar tools, her
fangs, and lines it with silk from her own body.
Our spider is an artist, evidently the master builder and architect of
her kind. Considering her soft and pussy-like appearance--no visible
drills for such rough work--one wonders how she excavates a burrow six
inches or more deep in this hard adobe soil of the Pacific coast, and
how she removes the dirt after she has loosened it. But she has been
surprised at her work; her tools are her two fangs, the same weapons
with which she seizes and dispatches her prey, and the rake or the
_cheliceræ_. To use these delicate instruments in such coarse work, says
Fabre, seems as "illogical as it would to dig a pit with a surgeon's
scalpel." And she carries the soil out in her mandibles, a minute pellet
at a time, and drops it here and there at some distance from her nest.
Her dooryard is never littered with it. It takes her one hour to dig a
hole the size of half an English walnut, and to remove the earth.
One afternoon I cut off the doors from two nests and left them turned
over, a few inches away. The next morning I found that the occupants of
the nests, under cover of the darkness, had each started the
construction of a new door, and had it about half finished. It seemed as
if the soil on the hinge side had begun to grow, and had put out a
semicircular bit of its surface toward the opposite side of the orifice,
each new door copying exactly the color of the ground that surrounded
it, one gray from dead vegetable matter, the other a light brick-red. I
read somewhere of an experimenter who found a nest on a mossy bit of
ground protectively colored in this way. He removed the lid and made the
soil bare about. The spider made a new lid and covered it with moss like
the old one, and her art had the opposite effect to what it had in the
first case. This is typical of the working of the insect mind. It seems
to know everything, and yet to know nothing, as we use the term "know."
On the second morning, one of the doors had attained its normal size,
but not yet its normal thickness and strength. It was much more artfully
concealed than the old one had been. The builder had so completely
covered it with small dry twigs about the size of an ordinary pin, and
had so woven these into it, standing a few of them on end, that my eye
was baffled. I knew to an inch where to look for the door, and yet it
seemed to have vanished. By feeling the ground over with a small stick I
found a yielding place which proved to be the new unfinished door. Day
after day the door grew heavier and stronger. The builder worked at it
on the under side, adding new layers of silk. There is always a layer of
the soil worked into the door to give it weight and strength.
Spiders, like reptiles, can go months without food. The young, according
to Fabre, go seven months without eating. They do not grow, but they are
very active; they expend energy without any apparent means of keeping up
the supply. How do they do it? They absorb it directly from the sun,
Fabre thinks, which means that here is an animal between which and the
organic world the vegetable chlorophyl plays no part, but which can take
at first-hand, from the sun, the energy of life. If this is true, and it
seems to be so, it is most extraordinary.
In view of the sex of the extraordinary spider I have been considering,
it is interesting to remember that one difference between the insect
world and the world of animal life to which we belong, which Maeterlinck
has forgotten to point out, is this:
In the vertebrate world, the male rules; the female plays a secondary
part. In the insect world the reverse is true. Here the female is
supreme and often eats up the male after she has been fertilized by him.
Motherhood is the primary fact, fatherhood the secondary. It is the
female mosquito that torments the world. It is the female spider that
spins the web and traps the flies. Size, craft, and power go with the
female. The female spider eats up the male after he has served her
purpose; her caresses mean death. The female scorpion devours the male
in the same way. Among our wild bees it is the queen alone that survives
the winter and carries on the race. The big noisy blow-flies on the
window-pane are females. With the honey bees the males are big and loud,
but are without any authority, and are almost as literally destroyed by
the female as is the male spider. The queen bee does not eat her mate,
but she disembowels him. The work of the hive is done by the neuters. In
the vertebrate world it is chiefly among birds of prey that the female
is the larger and bolder; the care of the young devolves largely upon
her. Yes, there is another exception: Among the fishes, the females are,
as a rule, larger than the males; the immense number of eggs which they
carry brings this about.
There are always exceptions to this dominance of the female in the
insect world. We cannot corner Nature and keep her cornered. She would
not be Nature if we could. With the fireflies, it is the male that
dominates; the female is a little soft, wingless worm on the ground,
always in the larval state.
In the plant world, also, the male as a rule is dominant. Behold the
showy catkins of the chestnuts, the butternuts, the hazelnuts, the
willows, and other trees. The stamens of most flowers are numerous and
conspicuous. Our Indian corn carries its panicle of pollen high above
the silken tresses which mother the future ear.
One day I dug up a nest which was occupied by a spider with her brood of
young ones. I took up a large block of earth weighing ten pounds or
more, and sank it in a box of earth of its own kind. I kept it in the
house under observation for a week, hoping that at some hour of day or
night the spider would come out. But she made no sign. My ingenious
friend arranged the same mechanical contrivance over the door which he
had used successfully before. But the latch was never lifted. Madam
Spider sulked or bemoaned her fate at the bottom of her den. At the end
of a week I broke open the nest and found her alone. She had evidently
devoured all her little ones.
I kept two nests with a spider in each in the house for a week, and in
neither case did the occupant ever leave its nest.
Apparently the young spiders begin to dig nests of their own when they
are about half-grown. As to where they stay, or how they live up to that
time, I have no clue. The young we found in several nests were very
small, not more than an eighth of an inch long. Of the size and
appearance of the male spider, and where he keeps himself, I could get
no clue.
One morning I went with my guide down to the spider territory, and saw
him try to entice or force a spider out of her den. The morning previous
he had beguiled several of them to come up to the opening by thrusting a
straw down the burrow and teasing them with it till in self-defense they
seized it with their fangs and hung on to it till he drew them to the
surface. But this morning the trick would not work. Not one spider would
keep her hold. But with a piece of wire bent at the end in the shape of
a hook, he finally lifted one out upon the ground. How bright and clean
and untouched she looked! Her limbs and a part of the thorax were as
black as jet and shone as if they had just been polished. No lady in her
parlor could have been freer from any touch of soil or earth-stain than
was she. On the ground, in the strong sunlight, she seemed to be lost.
We turned her around and tried to induce her to enter the nest again;
but over and over she ran across the open door without heeding it. In
the novel situation in which she suddenly found herself, all her wits
deserted her, and not till I took her between my thumb and finger and
thrust her abdomen into the hole, did she come to herself. The touch of
that silk-lined tube caused the proper reaction, and she backed quickly
into it and disappeared.
Just what natural enemy the trap-door spider has I do not know. I never
saw a nest that had been broken into or in any way disturbed, except
those which we had disturbed in our observations.