CATERPILLARS AT TABLE
“In the latter part of July the eggs hatch and through the covering of
down appear, here and there, little heads pushing aside the fluff that
is in their way. The first caterpillar hatched out crawls forward and
begins to browse on the upper surface of the leaf, grazing it lightly
and without eating through to the under surface or touching the veins;
it feeds only on the pulpy matter forming most of the leaf’s thickness.
As the hatching continues, another little caterpillar advances and
takes its place beside the first, then a third, a fourth, and so on
until the whole width of the leaf is occupied. In this way is formed
the first row of browsing caterpillars, all with heads in a straight
line and leaving in front a certain unoccupied space. The next
caterpillar to emerge from under the matting of down begins a second
row by taking its station at the tail of one of the preceding ones,
after which others place themselves at the right and left. This row
completed, a third is formed in the same manner, and then others, so
that in a short time the entire surface of the leaf except the forward
end is covered with rows of eaters. If one leaf is not enough for the
whole brood, the later comers establish themselves in like order on
neighboring leaves.
“There they are, then, all at table. The strictest discipline prevails
in this leafy dining-hall: each caterpillar gnaws what is directly
under its mandibles, without turning to right or left, as that would
take from its neighbor’s share; without advancing ahead of its own
line, as that would mean using the supplies of the future; and without
falling behind, as that would throw the rear ranks into confusion.
Under these conditions a few mouthfuls and no more fall to each
caterpillar. That is very little for a larva’s appetite. It must have
more, but how obtain it? Scatter abroad on other leaves, haphazard?
Undoubtedly there is plenty of room for all on the tree. But that would
be highly imprudent: they must keep together, for union is the strength
of the weak; they must keep together to be able to offer some sort of
formidable appearance to their enemies. It would be equally
objectionable for each to be a law to itself and gnaw where it chose on
the same leaf. The resulting confusion would cause waste, and also it
would be very difficult for each to get its proper share, some stuffing
themselves and others near by dying of hunger. In such absence of law
and order they would come to blows and fight desperately for a footing
on the leaf, so that civil war would soon thin their ranks, for there
is no worse counselor in such emergencies than the stomach. Order is
the only solution of their problem, order which safeguards human as
well as insect communities.”
“What do they do, then?” asked Jules.
“We are coming to that. Each caterpillar, as I said, gnaws only the
spot directly within reach. In this way there is left unbrowsed, first
the part covered by each body, and then the forward part of the leaf,
which is still unoccupied. The first row of caterpillars advances one
step and finds a second ration in the part thus reached; but at the
same time it uncovers in the rear a crosswise strip one step wide,
which the second row now advances to feed upon, while in its turn it
leaves a similar strip free for the third row; and so on. One step
forward for the whole troop puts each row in possession of the strip
left uncovered by the preceding row. As for the first row, it feeds
little by little on the forward part of the leaf, designedly left
unoccupied in the beginning. When step by step the very end of the leaf
is reached, each caterpillar has gnawed a strip as long and as wide as
its own body. By that time the first meal is finished. You see that
with order and economy a hundred and more caterpillars all have a place
in the dining-hall on the surface of the leaf, and all have as nearly
equal rations as if these had been allotted by weight and measure.”
“Animals with their instinct are wonderful creatures, Uncle,” observed
Jules. “Every day brings some fresh surprise.”
“It is not the creature itself that is to be wondered at, my dear
child; the marvels it accomplishes are not the fruit of its reflection.
A grub just out of the egg can have no ideas on method, economy,
coöperation, when in order to acquire these ideas man needs the full
maturity of his reason. Our tribute of admiration should be paid to the
Infinite Wisdom which governs the world and leads a brood of
caterpillars browsing the surface of a leaf.
“Their first hunger appeased, the caterpillars construct a shelter from
rain and the heat of the sun. On its gnawed side the leaf is dryer than
on the other, and consequently has of itself taken a kind of concave
shape by curling up, which makes it serve excellently for the floor and
walls of the new abode. As for the ceiling, that is to be of silk. From
one raised edge of the leaf to the other the caterpillars stretch
threads to strengthen their shelter and serve as framework for the
roof, and finally they weave a fabric on this network of threads. Thus
is erected a tent under which the caterpillars take refuge for the
night after roaming over the foliage most of the day, feeding sometimes
on one leaf, sometimes on another. Thither also they retire when the
heat is excessive or the weather threatening. It is a shelter hastily
constructed and not of enduring quality, besides being too small to
hold them all. So other tents are made of other gnawed leaves, and the
caterpillars live for a while divided into small families.
“But with the first rain-storms of autumn, in September or October, a
large building is constructed for housing the whole colony through the
winter. It is a bulky mass of dry leaves and white silk, with no
definite shape. The inside is divided with silk partitions into
numerous apartments to which there is access through holes that pierce,
systematically, the several partitions. Each enclosure thus has its
doors which, without being directly opposite each other, yet provide
free circulation. In short, this common nest, though made of extremely
fine silk, is substantial enough to be proof against wind and weather,
for the caterpillars use many webs, placed one over another and each
containing a great number of threads. With the coming of the first cold
weather all shut themselves up, the doors are barricaded with silk, and
everything is made snug for the winter. Now let the wind blow and the
snow fall! Curled up together and snuggling against one another, the
caterpillars sleep the deep sleep produced by the cold, lying torpid in
their house of silk until the warmth of opening spring awakens them and
sends them forth to browse on the growing leaves.”
“And don’t they eat anything all winter?” asked Emile.
“All winter as well as a part of the autumn and spring they take no
food whatever. Their fast lasts six months, and it is an absolute fast
that must leave them with very empty stomachs.”
“They must be awfully hungry when they wake up.”
“So hungry that they make a dash for the tender young leaves and
opening flowers, and in less than no time strip an orchard bare. If the
nests are very numerous whole forests are browsed to the last leaf.”
“And then?”
“To prevent these ravages the mayor’s notice is heeded. Some time in
the winter these terrible bags of dry leaves and silk are detached from
the trees, hedges, and bushes, and the nests with their occupants are
burned. In spring it would be too late: the caterpillars would all have
left their quarters.”