Not many years ago it was confidently asserted that “Man is the only
tool-using animal.” Now we know that not only do members of the Ape
family employ sticks for weapons and even for crowbars, and also use
various objects for missiles, but even in the Insect world we find a
creature, the Solitary Wasp (Ammophila), which makes a door of soft
earth for its nest and then picks up a small pebble in its mandibles
and hammers the edges of the door more securely, just as a man would
use a pounding-iron. This phenomenon, observed by the Peckhams in
1898,[16] has been verified by other investigators.
“Before we could recover from our astonishment at this performance,”
wrote these now famous observers, “she had dropped her stone and was
bringing more earth, and in a moment we saw her pick up the pebble and
again pound the earth into place with it. Once more the whole process
was repeated, and then the little creature flew away.”
Professor Thomson came to the conclusion that the Wasp’s use of the
pebble for a mallet “is not part of the instinctive routine but is an
individual touch, probably with more vivid awareness than is associated
with the rest of the agency. The difficulty is to think of the origin
of either the routine or the finishing touch without postulating
intelligence or at least some appreciation of significance.”
Bouvier points out that the use of the little stone is not yet a fixed
habit with Ammophila urania, belonging “only to certain individuals
more highly endowed than others, and is perhaps only accidental even
with them. Maybe it will finally pass into the instinctive habits of
the species; for the present it belongs to the domain of individual
intelligent acts.”
It should here be noted that in the psychological history of the
Articulata we witness the gradual transformation of intelligent acts
into instinctive acts, whereas the path of evolution in the Vertebrates
seems to lead from instinct toward intelligence. It is reasonable to
infer, however, that the instincts of the Vertebrates were preceded by
an intelligent process and the establishment of new habits, “which by
heredity became part of the patrimony of instinct, modifying the latter
and constituting elements essential to its evolution.” (Bouvier, E.
L., “La vie psychique des Insectes.”) “It is intelligence,” continues
this same high authority, that “regulates by appropriate selection
all manifestations of race memory; intelligence again, in the sundry
forms of association and individual memory, that puts together the most
complicated mechanisms of instincts.”
We are still told by many writers that the Insects are mere reflex
machines, despite abundant evidences to the contrary. “This machine,”
says M. de Molostwoff, “has no capacity for reasoning and lives as its
body directs it to live. Man, however, is the only animal endowed with
a will to live according to his reason, [does he?] and he alone is
amenable for his actions to his Creator.”
The Wasp may, indeed, “live as its body directs it to live,” but this,
according to many modern thinkers, is precisely what Man himself does,
his “capacity for reasoning” being conditioned by heredity, largely
controlled by “instinct,” and by his bodily structure and internal
reactions--actions, reactions and interactions of the vegetative
organism (viscera, glands, etc.) as well as the cerebro-spinal system.
And just so the Ammophila Wasp may be a physico-chemical-biotic machine
and yet possess the “capacity for reasoning,” yet at the same time
“live as its body directs it to live”--its reasoning power being part
and parcel of its organism as a whole.[17]
Lacordaire, in his well known “_Introduction a l’Entomologie_,” says of
Insects:
“If all the instinctive acts of Insects bore constantly the evident
imprint of a blind necessity, there would be much less to admire in
them than one commonly does. What particularly excites our surprise
is that frequently they accommodate themselves to circumstances, and
that their acts take on then such an appearance of reason, that it is
necessary to look at them closely not to attribute them to a veritable
combination of ideas.”
“Insects are largely creatures of instinct,” remarks Professor Thomson,
“with inborn capacities for doing apparently clever things, but yet
with some degree of intelligence. In an animal’s behavior there is
often, no doubt, a mingling of different kinds of activities unified
in a way that baffles analysis. In many cases their behavior under new
conditions, their powers of effectively meeting new ends, go beyond
mere instinct.”
Prof. J. Lloyd Morgan was led to the conclusion that we have in the
case of the tool-using wasp “intelligent behavior rising to a level to
which some would apply the term rational. For the act may be held to
afford evidence of the perception of the relation of the means employed
to an end to be attained, and some general conception of purpose.”
Professor Holmes expresses a doubt on this question: “Does she really
perceive the relation of means to end? I am not so sure that she does.”
While it is certainly better to be over-cautious than to be inclined to
anthropomorphic interpretations where physico-chemical and mechanical
or other solutions meet the requirements of the case, there is,
nevertheless, such a thing as avoiding an interpretation involving the
recognition of a reasoning process in animals just for the sake of
“conservatism.” There is no more merit in referring all phenomena to
“instinctive behavior” in animals than there would be in attributing
all acts of Man to “reasoning.” As matters stand today, the pendulum
of thought has swung so far away from the “anthropomorphism of earlier
writers” that we are apt to throw a sort of intellectual smoke-screen
over a truly rational act by recourse to “the animal’s instinctive
actions.”
Again, our “experiments” with animals are by no means a safe guide
to accurate estimates of their mental attainments. Measurement of
an animal’s real mental endowment may be far more safely made by
observation of its behavior in its natural environment. That this
is true is fully recognized by scientists who deplore the tendency
of some observers to draw conclusions before becoming thoroughly
acquainted with the general behavior of the forms observed. “On the
other hand,” says Professor Holmes, “one is tortured by the feeling
that our experimental methods often fail to give us a true measure
of an animal’s possible attainments, and that it is just in meeting
exceptional situations which occur in the animal’s natural course of
life that the highest manifestations of its intelligence are reached.”
Wasps of the genus Eumenes are said to mould tempered earth into
pottery of the most artistic design.
Fabre tells us that the ringed Calicurgus Wasp first stings its
captured Spider in a spot near the mouth, paralyzing the poison claws.
This precaution being taken, it proceeds to pick out the thinnest part
of the Spider’s armor, between the fourth pair of legs, driving in its
poison needle with a skilled surgeon’s precision.
The Two-banded Scolia Wasp lays up as food for its larva a Rose-chafer
grub. A single grub is the sole provender for the larva for the several
weeks from its hatching until its entrance into the cocoon stage. It
has frequently been stated that the “head of game” must remain fresh
all the time the Wasp larva is feeding on it, or the Wasp larva dies.
To remain fresh it must stay alive until the larva takes its last
mouthful.
To insure this, a complicated course must be followed with delicate
precision by both the mother Wasp and the larva. With a single and
seldom-erring stroke of its sting Scolia paralyzes the nerve-centers
which control motion on the Rose-chafer grub--a stroke which must reach
a buried nerve-center no more than a fiftieth of an inch across, and
which must at the same time miss the nerve-center which keeps life in
the victim.
The infant Scolia must then, to keep its food fresh to the end, so eat
its living but paralyzed grub that the vital parts are left to the
last meal. Accordingly, the Scolia lays its egg always at the precise
spot on the Rose-chafer grub where the Wasp larva must take its first
mouthful. There the larva inserts its head and never withdraws it until
the grub is completely devoured. Fabre found by repeated experiment
that if he disturbed the larva the chances were even that it lost the
clue to its selective meal, killed its “game” and died of ptomaines. If
he moved the recently hatched larva to another starting-place on its
food supply it was infallibly lost. So it was also when Fabre gave it
as food another grub, even though closely related to the Rose-chafer.
It tried to eat the strange nutrient, but somehow never succeeded.
Hence, according to most authorities at least, it is a prerequisite to
the survival of Scolia that the mother Wasp select only the Rose-chafer
grub, capable of being paralyzed in such a way as to leave the grub
alive but without power to move. In all, there are four critical
conditions to be met in order that the progeny survive: and they are
met.
In their studies of the Mason Wasp, Odynerus parietum, the Peckhams
found that, contrary to Eimer, the grubs stored for food for the
larvæ were by no means all paralyzed, and that in most nests several
caterpillars died. In some cases all the grubs died, yet the Wasp larvæ
fed upon them without apparent injury or dissatisfaction.
Holmes remarks that while we may not be compelled to admit that
Wasps have “ideas,” it must be granted, he thinks, “that a Wasp
which after cutting a caterpillar in two and carrying away one part,
came back and searched diligently for the remainder” retained,
somehow, “an impression of the missing part and its location. If
out of sight it was not out of mind.... If the Wasp does not have
an idea of its prey it has something which plays a rôle similar to
that of ideas in ourselves.... If there is something representing
‘part-of-caterpillar-among-leaves’ that leads the Wasp on its
hunt, we may conclude that there is something corresponding to
‘part-of-caterpillar-now-in-nest’ which prevents further search.”