Chapter VI. The Narbonne Lycosa: the Climbing-Instinct
Jean-Henri Fabre The Life of the Spider
Tarantula (Lycosa Narbonensis)
The month of March comes to an end; and the departure of the youngsters begins, in glorious weather, during the hottest hours of the morning. Laden with her swarming burden, the mother Lycosa is outside her burrow, squatting on the parapet at the entrance. She lets them do as they please; as though indifferent to what is happening, she exhibits neither encouragement nor regret. Whoso will goes; whoso will remains behind.
First these, then those, according as they feel themselves duly soaked with sunshine, the little ones leave the mother in batches, run about for a moment on the ground and then quickly reach the trellis-work of the cage, which they climb with surprising alacrity. They pass through the meshes, they clamber right to the top of the citadel. All, with not one exception, make for the heights, instead of roaming on the ground, as might reasonably be expected from the eminently earthly habits of the Lycosae; all ascend the dome, a strange procedure whereof I do not yet guess the object.
I receive a hint from the upright ring that finishes the top of the cage. The youngsters hurry to it. It represents the porch of their gymnasium. They hang out threads across the opening; they stretch others from the ring to the nearest points of the trellis-work. On these foot-bridges, they perform slack-rope exercises amid endless comings and goings. The tiny legs open out from time to time and straddle as though to reach the most distant points. I begin to realize that they are acrobats aiming at loftier heights than those of the dome.
I top the trellis with a branch that doubles the attainable height. The bustling crowd hastily scrambles up it, reaches the tip of the topmost twigs and thence sends out threads that attach themselves to every surrounding object. These form so many suspension-bridges; and my beasties nimbly run along them, incessantly passing to and fro. One would say that they wished to climb higher still. I will endeavour to satisfy their desires.
I take a nine-foot reed, with tiny branches spreading right up to the top, and place it above the cage. The little Lycosae clamber to the very summit. Here, longer threads are produced from the rope-yard and are now left to float, anon converted into bridges by the mere contact of the free end with the neighbouring supports. The rope-dancers embark upon them and form garlands which the least breath of air swings daintily. The thread is invisible when it does not come between the eyes and the sun; and the whole suggests rows of Gnats dancing an aerial ballet.
Then, suddenly, teased by the air-currents, the delicate mooring breaks and flies through space. Behold the emigrants off and away, clinging to their thread. If the wind be favourable, they can land at great distances. Their departure is thus continued for a week or two, in bands more or less numerous, according to the temperature and the brightness of the day. If the sky be overcast, none dreams of leaving. The travellers need the kisses of the sun, which give energy and vigour.
At last, the whole family has disappeared, carried afar by its flying-ropes. The mother remains alone. The loss of her offspring hardly seems to distress her. She retains her usual colour and plumpness, which is a sign that the maternal exertions have not been too much for her.
I also notice an increased fervour in the chase. While burdened with her family, she was remarkably abstemious, accepting only with great reserve the game placed at her disposal. The coldness of the season may have militated against copious refections; perhaps also the weight of the little ones hampered her movements and made her more discreet in attacking the prey.
To-day, cheered by the fine weather and able to move freely, she hurries up from her lair each time I set a tit-bit to her liking buzzing at the entrance to her burrow; she comes and takes from my fingers the savoury Locust, the portly Anoxia (1); and this performance is repeated daily, whenever I have the leisure to devote to it. After a frugal winter, the time has come for plentiful repasts.
This appetite tells us that the animal is not at the point of death; one does not feast in this way with a played-out stomach. My boarders are entering in full vigour upon their fourth year. In the winter, in the fields, I used to find large mothers, carting their young, and others not much more than half their size. The whole series, therefore, represented three generations. And now, in my earthenware pans, after the departure of the family, the old matrons still carry on and continue as strong as ever. Every outward appearance tells us that, after becoming great-grandmothers, they still keep themselves fit for propagating their species.
The facts correspond with these anticipations. When September returns, my captives are dragging a bag as bulky as that of last year. For a long time, even when the eggs of the others have been hatched for some weeks past, the mothers come daily to the threshold of the burrow and hold out their wallets for incubation by the sun. Their perseverance is not rewarded: nothing issues from the satin purse; nothing stirs within. Why? Because, in the prison of my cages, the eggs have had no father. Tired of waiting and at last recognizing the barrenness of their produce, they push the bag of eggs outside the burrow and trouble about it no more. At the return of spring, by which time the family, if developed according to rule, would have been emancipated, they die. The mighty Spider of the waste-lands, therefore, attains to an even more patriarchal age than her neighbour the Sacred Beetle (2): she lives for five years at the very least.
Let us leave the mothers to their business and return to the youngsters. It is not without a certain surprise that we see the little Lycosae, at the first moment of their emancipation, hasten to ascend the heights. Destined to live on the ground, amidst the short grass, and afterwards to settle in the permanent abode, a pit, they start by being enthusiastic acrobats. Before descending to the low levels, their normal dwelling-place, they affect lofty altitudes.
To rise higher and ever higher is their first need. I have not, it seems, exhausted the limit of their climbing-instinct even with a nine-foot pole, suitably furnished with branches to facilitate the escalade. Those who have eagerly reached the very top wave their legs, fumble in space as though for yet higher stalks. It behoves us to begin again and under better conditions.
Although the Narbonne Lycosa, with her temporary yearning for the heights, is more interesting than other Spiders, by reason of the fact that her usual habitation is underground, she is not so striking at swarming-time, because the youngsters, instead of all migrating at once, leave the mother at different periods and in small batches. The sight will be a finer one with the common Garden or Cross Spider, the Diadem Epeira (Epeira diadema, LIN.), decorated with three white crosses on her back.
She lays her eggs in November and dies with the first cold snap. She is denied the Lycosa's longevity. She leaves the natal wallet early one spring and never sees the following spring. This wallet, which contains the eggs, has none of the ingenious structure which we admired in the Banded and in the Silky Epeira. No longer do we see a graceful balloon-shape nor yet a paraboloid with a starry base; no longer a tough, waterproof satin stuff; no longer a swan's-down resembling a fleecy, russet cloud; no longer an inner keg in which the eggs are packed. The art of stout fabrics and of walls within walls is unknown here.
The work of the Cross Spider is a pill of white silk, wrought into a yielding felt, through which the new-born Spiders will easily work their way, without the aid of the mother, long since dead, and without having to rely upon its bursting at the given hour. It is about the size of a damson.
We can judge the method of manufacture from the structure. Like the Lycosa, whom we saw, in Chapter III., at work in one of my earthenware pans, the Cross Spider, on the support supplied by a few threads stretched between the nearest objects, begins by making a shallow saucer of sufficient thickness to dispense with subsequent corrections. The process is easily guessed. The tip of the abdomen goes up and down, down and up with an even beat, while the worker shifts her place a little. Each time, the spinnerets add a bit of thread to the carpet already made.
When the requisite thickness is obtained, the mother empties her ovaries, in one continuous flow, into the centre of the bowl. Glued together by their inherent moisture, the eggs, of a handsome orange-yellow, form a ball-shaped heap. The work of the spinnerets is resumed. The ball of germs is covered with a silk cap, fashioned in the same way as the saucer. The two halves of the work are so well joined that the whole constitutes an unbroken sphere.
The Banded Epeira and the Silky Epeira, those experts in the manufacture of rainproof textures, lay their eggs high up, on brushwood and bramble, without shelter of any kind. The thick material of the wallets is enough to protect the eggs from the inclemencies of the winter, especially from damp. The Diadem Epeira, or Cross Spider, needs a cranny for hers, which is contained in a non-waterproof felt. In a heap of stones, well exposed to the sun, she will choose a large slab to serve as a roof. She lodges her pill underneath it, in the company of the hibernating Snail.
More often still, she prefers the thick tangle of some dwarf shrub, standing eight or nine inches high and retaining its leaves in winter. In the absence of anything better, a tuft of grass answers the purpose. Whatever the hiding-place, the bag of eggs is always near the ground, tucked away as well as may be, amid the surrounding twigs.
Save in the case of the roof supplied by a large stone, we see that the site selected hardly satisfies proper hygienic needs. The Epeira seems to realize this fact. By way of an additional protection, even under a stone, she never fails to make a thatched roof for her eggs. She builds them a covering with bits of fine, dry grass, joined together with a little silk. The abode of the eggs becomes a straw wigwam.
Good luck procures me two Cross Spiders' nests, on the edge of one of the paths in the enclosure, among some tufts of ground-cypress, or lavender-cotton. This is just what I wanted for my plans. The find is all the more valuable as the period of the exodus is near at hand.
I prepare two lengths of bamboo, standing about fifteen feet high and clustered with little twigs from top to bottom. I plant one of them straight up in the tuft, beside the first nest. I clear the surrounding ground, because the bushy vegetation might easily, thanks to threads carried by the wind, divert the emigrants from the road which I have laid out for them. The other bamboo I set up in the middle of the yard, all by itself, some few steps from any outstanding object. The second nest is removed as it is, shrub and all, and placed at the bottom of the tall, ragged distaff.
The events expected are not long in coming. In the first fortnight in May, a little earlier in one case, a little later in the other, the two families, each presented with a bamboo climbing-pole, leave their respective wallets. There is nothing remarkable about the mode of egress. The precincts to be crossed consist of a very slack net-work, through which the outcomers wriggle: weak little orange-yellow beasties, with a triangular black patch upon their sterns. One morning is long enough for the whole family to make its appearance.
By degrees, the emancipated youngsters climb the nearest twigs, clamber to the top, and spread a few threads. Soon, they gather in a compact, ball-shaped cluster, the size of a walnut. They remain motionless. With their heads plunged into the heap and their sterns projecting, they doze gently, mellowing under the kisses of the sun. Rich in the possession of a thread in their belly as their sole inheritance, they prepare to disperse over the wide world.
Let us create a disturbance among the globular group by stirring it with a straw. All wake up at once. The cluster softly dilates and spreads, as though set in motion by some centrifugal force; it becomes a transparent orb wherein thousands and thousands of tiny legs quiver and shake, while threads are extended along the way to be followed. The whole work resolves itself into a delicate veil which swallows up the scattered family. We then see an exquisite nebula against whose opalescent tapestry the tiny animals gleam like twinkling orange stars.
This straggling state, though it last for hours, is but temporary. If the air grow cooler, if rain threaten, the spherical group reforms at once. This is a protective measure. On the morning after a shower, I find the families on either bamboo in as good condition as on the day before. The silk veil and the pill formation have sheltered them well enough from the downpour. Even so do Sheep, when caught in a storm in the pastures, gather close, huddle together and make a common rampart of their backs.
The assembly into a ball-shaped mass is also the rule in calm, bright weather, after the morning's exertions. In the afternoon, the climbers collect at a higher point, where they weave a wide, conical tent, with the end of a shoot for its top, and, gathered into a compact group, spend the night there. Next day, when the heat returns, the ascent is resumed in long files, following the shrouds which a few pioneers have rigged and which those who come after elaborate with their own work.
Collected nightly into a globular troop and sheltered under a fresh tent, for three or four days, each morning, before the sun grows too hot, my little emigrants thus raise themselves, stage by stage, on both bamboos, until they reach the sun-unit, at fifteen feet above the ground. The climb comes to an end for lack of foothold.
Under normal conditions, the ascent would be shorter. The young Spiders have at their disposal the bushes, the brushwood, providing supports on every side for the threads wafted hither and thither by the eddying air-currents. With these rope-bridges flung across space, the dispersal presents no difficulties. Each emigrant leaves at his own good time and travels as suits him best.
My devices have changed these conditions somewhat. My two bristling poles stand at a distance from the surrounding shrubs, especially the one which I planted in the middle of the yard. Bridges are out of the question, for the threads flung into the air are not long enough. And so the acrobats, eager to get away, keep on climbing, never come down again, are impelled to seek in a higher position what they have failed to find in a lower. The top of my two bamboos probably fails to represent the limit of what my keen climbers are capable of achieving.
We shall see, in a moment, the object of this climbing-propensity, which is a sufficiently remarkable instinct in the Garden Spiders, who have as their domain the low-growing brushwood wherein their nets are spread; it becomes a still more remarkable instinct in the Lycosa, who, except at the moment when she leaves her mother's back, never quits the ground and yet, in the early hours of her life, shows herself as ardent a wooer of high places as the young Garden Spiders.
Let us consider the Lycosa in particular. In her, at the moment of the exodus, a sudden instinct arises, to disappear, as promptly and for ever, a few hours later. This is the climbing-instinct, which is unknown to the adult and soon forgotten by the emancipated youngling, doomed to wander homeless, for many a long day, upon the ground. Neither of them dreams of climbing to the top of a grass-stalk. The full-grown Spider hunts trapper-fashion, ambushed in her tower; the young one hunts afoot through the scrubby grass. In both cases there is no web and therefore no need for lofty contact-points. They are not allowed to quit the ground and climb the heights.
Yet here we have the young Lycosa, wishing to leave the maternal abode and to travel far afield by the easiest and swiftest methods, suddenly becoming an enthusiastic climber. Impetuously she scales the wire trellis of the cage where she was born; hurriedly she clambers to the top of the tall mast which I have prepared for her. In the same way, she would make for the summit of the bushes in her waste-land.
We catch a glimpse of her object. From on high, finding a wide space beneath her, she sends a thread floating. It is caught by the wind and carries her hanging to it. We have our aeroplanes; she too possesses her flying-machine. Once the journey is accomplished, naught remains of this ingenious business. The climbing-instinct conies suddenly, at the hour of need, and no less suddenly vanishes.
1. A species of Beetle.
2. Cf. Insect Life, by J. H. Fabre, translated by the author of Mademoiselle Mori: chaps. i. and ii.; The Life and Love of the Insect, by J. Henri Fabre, translated by Alexander Teixeira de Mattos: chaps. i. to iv.