THE TRAVELLERS

I have told in the last chapter how, on the ridges of Mont Ventoux, at a height of nearly 6000 feet, I had one of those entomological windfalls which would be rich in results if they occurred often enough to serve the purpose of continuous study. Unfortunately, mine was a solitary instance and I despair of ever repeating it. I can therefore only base conjectures on it, in the hope that future observers will replace my surmises with certainties.

Under the shelter of a broad, flat stone I discovered some hundreds of Ammophilæ (A. hirsuta), heaped one on top of the other almost as closely as the Bees in a swarm. As soon as I lifted the stone, all this little hairy world began to run about, without making any attempt to fly away. I shifted the mass by handfuls: not one of the Wasps looked as though she wished to desert the rest. They seemed indissolubly united by common interests; none of them would go unless all went. I examined with every possible care the flat stone that sheltered them, as well as the ground underneath and just around it, and discovered not a thing to tell me the cause of this strange assemblage. Having nothing better left to do, I tried to count them; and it was then that the clouds came and put an end to my observations and plunged us into that darkness of which I have described the anxious consequences. At the first drops of rain, before leaving the spot, I hastened to put back the stone and replace the Ammophilæ in their shelter. I give myself a good mark, which I hope that the reader will confirm, for having taken the precaution not to leave the poor insects whom my curiosity had disturbed at the mercy of the downpour.

The Hairy Ammophila is not rare in the plains, but she is always found singly by the side of the paths or on the sandy slopes, now engaged in digging her well, anon busily carting her heavy caterpillar. She lives alone, like the Languedocian Sphex; and it was a great surprise to me to come upon such a number of this species collected under one and the same stone almost at the top of Mont Ventoux. Instead of the isolated specimen which I had known hitherto, a crowded company presented itself to my eyes. Let us try to trace the probable causes of this agglomeration.

The Hairy Ammophila is one of the very rare exceptions among the Digger-wasps in the matter of nest-building; she gets hers ready in the early days of spring. Towards the end of March, if the season be mild, or at latest in the first fortnight of April, when the Crickets assume the adult form and laboriously cast the skin of infancy on the threshold of their homes, when the poet’s-narcissus puts forth its first flowers and the Bunting utters his long-drawn call from the top of the poplars in the fields, Ammophila hirsuta is at work digging a home for her grubs and victualling it, whereas the other Ammophilæ and the various Hunting Wasps in general postpone this labour until autumn, during September and October. This early nidification, preceding by six months the date adopted by the vast majority, at once suggests a few reflections.

We wonder if the Ammophilæ whom we find occupied with their burrows in the first days of April are really insects of that year, that is to say, if these spring workers completed their metamorphosis and left their cocoons during the previous three months. The general rule is for the Digger to become a perfect insect, to quit her subterranean dwelling and to busy herself with her larvæ all in one season. Most of the Predatory Wasps leave the galleries where they lived as larvæ in the months of June and July and display their talents as miners and hunters in the following months of August, September and October.

Does a similar law apply to the Hairy Ammophila? Does the same season witness the insect’s final transformation and its labours? It is very doubtful, for the Wasp occupied on the work of the burrow at the end of March would in that case have to complete her metamorphosis and to break out of her cocoon during the winter, or at latest in February. The severity of the climate at this period does not allow us to accept such a conclusion. It is not at a time when the bleak mistral howls for a fortnight without intermission and freezes the ground hard, it is not at a time when snowstorms follow close upon that icy blast, that the delicate transformations of the nymphosis are able to take place or the insect to dream of abandoning the shelter of its cocoon. It needs the warm moisture of the earth under the summer sun before it can leave its cell.

If I knew the exact period at which the Hairy Ammophila emerges from her native burrow, this would help me greatly; but, to my intense regret, I do not know it. My notes, collected day by day, with the lack of order inevitable in a type of research that is constantly subject to the hazards of the unforeseen, are silent on this point, of which I clearly perceive the importance now that I am trying to arrange my materials in order to write these lines. I find the Sandy Ammophila mentioned as hatching on the 5th of June and the Silvery Ammophila on the 20th of that month; but my records contain not a word that relates to the hatching of the Hairy Ammophila. It is a detail which, by an oversight, has never been cleared up. The dates given for the other two species come under the general law, which lays down that the perfect insect shall appear during the hot season. I fix the same period, by analogy, as that for the Hairy Ammophila’s emergence from the cocoon.

Then whence come the Ammophilæ whom we see working at their burrows at the end of March and in April? We are driven to the conclusion that these Wasps belong not to the present but to the previous year; that they left their cells at the usual time, in June and July, got through the winter and began to make their nests as soon as the spring came. In a word, they are hibernating insects. And this conclusion is fully borne out by experiment.

If we will but search patiently in the perpendicular banks of earth or sand facing due south, especially those in which generations of different honey-gathering Bees have succeeded one another year after year and riddled the wall with a labyrinth of tunnels until it looks like an enormous sponge, we are almost sure, in midwinter, to find the Hairy Ammophila snugly ensconced in the shelters provided by the sunny bank, alone or in groups of three or four, idly awaiting the arrival of the fine weather. I have been able to give myself as often as I wished this little treat of renewing my acquaintance, amid the gloom and cold of winter, with the pretty Wasp who enlivens the greensward beside the paths at the first notes of the Bunting and the Cricket. When there is no wind and the sun is shining brightly, the warmth-loving insect comes to its threshold to bask luxuriously in the hottest rays, or it will even timidly venture outside and, step by step, stroll over the surface of the spongy bank, polishing its wings as it goes. Even so does the little Grey Lizard behave, when the sun once more begins to warm the old wall that represents his native land.

But vain would be our search in winter, even in the most sheltered refuges, for a Cerceris, Sphex, Philanthus, Bembex or other Wasp with carnivorous grubs. All died after their autumnal labours and their race is not represented, in the cold season, save by the larvæ slumbering in their cells. It is, then, by a most rare exception that the Hairy Ammophila, hatched in the hot season, spends the following winter in some warm shelter; and this is the reason why she appears so very early in the spring.

With these data to go upon, let us try to explain the cluster of Ammophilæ which I observed on the ridges of Mont Ventoux. What could these numerous Wasps have been doing, heaped up under their stone? Were they preparing to take up their winter quarters there and, slumbering under cover, to await the season favourable to their work? Everything tends to show that this is improbable. It is not in August, at the hottest time of year, that an animal is overcome with its winter drowsiness. Nor is it any use to suggest the want of food, of honeyed juices sucked from the flowers. The September showers are at hand; and vegetation, suspended for a moment by the heat of the dog-days, will gather fresh vigour and cover the fields with blossoms almost as diverse as those of spring. This season of revelry for the majority of Wasps and Bees could never be a period of torpor for the Hairy Ammophila.

And then have we any right to imagine that the heights of Ventoux, swept by the gusts of the mistral, which sometimes uproots both beech and pine; that crests where the north wind sends the snow-flakes whirling for six months in succession; that peaks wrapped for the best part of the year in cold cloud-fogs, can be adopted as a winter refuge by an insect enamoured of the sun? One might as well suggest that it should hibernate among the ice-floes of the North Cape. No, it is not here that the Hairy Ammophila can spend the cold season. The group which I observed was only passing through. At the first hint of rain, a hint that escaped us but could not escape the insect, which is so highly sensitive to the atmospheric variations, the band of travellers had taken shelter under a stone, waiting for the rain to stop before resuming their flight. Whence did they come? Whither were they bent?

In this same month of August, and still more in September, we are visited, in our warm, olive-clad regions, by caravans of little birds of passage descending by easy stages from the countries where they have wooed and loved, countries cooler, more thickly wooded, less wild than ours, where they have reared their broods. They arrive almost on a fixed day, in an unvarying order, as though guided by the dates of a calendar known only to themselves. They sojourn for some time in our plains, a halting-place rich in insects, which form the exclusive fare of most of them; they ransack every clod in our fields, where the ploughshare by now has laid bare in the furrows a multitude of grubs, their special delight; thanks to this diet, they soon put on a fine cushion of fat, a storehouse of reserve provisions for the coming exertions; and at last, supplied with this viaticum, they continue their southward flight, making for the winterless lands where insects are never lacking: Spain, Southern Italy, the Mediterranean islands and Africa. This is the season for brave sport with the gun and for dainty roasts of small birds.

The first to arrive is the Shore-lark, or, as he is called in these parts, the Crèou. August is hardly here before we see him exploring the pebbly fields, in search of the little seeds of setaria, an ill weed that overruns our tilled soil. At the least alarm he flies away with a harsh clattering in his throat which is not badly represented by his Provençal name. He is soon followed by the Whin-chat, who preys placidly on small Weevils, Locusts, and Ants in the old lucern-fields. With him begins the long line of small winged things, the glory of the spit. It is continued, when September comes, by the most famous of them, the Common Wheat-ear, or White-tail, extolled by all who are able to appreciate his exalted qualities. No Beccafico of the Roman epicures, immortalized in Martial’s epigrams, ever equalled the exquisite, scented ball of fat that is the Wheat-ear, grown shamefully stout on gluttonous living. He is an unbridled devourer of every kind of insect. The notes which I have taken as a sportsman and naturalist bear witness to the contents of his gizzard. It includes the whole little world of the fallow fields: grubs and Weevils of every species, Locusts, Tortoise-beetles, Golden Apple-beetles, Crickets, Earwigs, Ants, Spiders, Wood-lice, Snails, Millipedes, and ever so many others. And, as a change from this full-flavoured diet, there are grapes, blackberries and dogberries. Such is the bill of fare for which the Wheat-ear is ever in search, as he flies from clod to clod, with the white feathers of his outspread tail giving him that fictitious look of a Butterfly on the wing. And Heaven knows what prodigies of plumpness he is able to achieve.

He has only one master in the art of self-fattening. This is one whose migration synchronizes with his, one who is likewise an enthusiastic insect-eater: the Bush-pipit, as the nomenclators so absurdly call him, whereas the dullest of our shepherds never hesitates to speak of him as the Grasset, the champion fat bird. The name in itself fully describes his leading characteristic. No other achieves such a degree of obesity. A moment comes when, laden with pads of fat up to its wings, its neck and the back of its head, the bird looks like a little pat of butter. The poor thing can hardly flutter from one mulberry-tree to the next, where it stops to pant in the thick leafage, half choked with melting fat, a martyr to its passion for Weevils.

October brings us the slender White Wagtail, half pearly grey, half white, with a large black-velvet chest-protector. The graceful little bird, trotting along and cocking up its tail, follows the ploughman almost under the horses’ feet and picks the grubs in the new-turned furrow. About the same time the Skylark arrives, first in little companies sent out as scouting-parties, next in countless battalions, which take possession of the cornfields and fallow land, with their plentiful setaria-seeds, the bird’s usual fare. Then, in the plain, amid the universal glitter of dewdrops and rime-crystals hanging from every blade of grass, the treacherous mirror shoots forth its intermittent flashes in the rays of the morning sun; then the little Owl, released by the hunter’s hand, makes his short flight, alights, starts up again convulsively, rolling frightened eyes; and the Lark arrives, dipping on the wing, curious to obtain a closer view of the bright apparatus or the grotesque bird. He is there, in front of you, a dozen yards away, with feet pendant and wings outspread like the Dove in a sacred picture. Now then: take aim and fire! I wish my readers the excitement of this fascinating sport.

With the Skylark, often in the same companies, comes the Titlark, commonly called the Sisi. Here again an onomatopœia gives us the bird’s little call-note. None goes with greater fury for the Owl, round whom he manœuvres and hovers constantly. But we will not continue the list of the birds of passage that visit us. Most of them make but a short halt here; they stay for a few weeks, attracted by the abundance of food, especially of insects; then, plump and strong, they pursue their southward journey. Others, fewer these, take up their winter quarters in our plains, where snow is very rare and where thousands of little seeds lie exposed on the ground, even in the depth of winter. One of these is the Skylark, who gives his attention to the corn-fields and fallows; another is the Titlark, who prefers the lucern-fields and meadows.

The Skylark, so common in almost every part of France, does not nest in the Vaucluse plains, where his place is taken by the Crested Lark, that frequenter of the broad highway, the roadmender’s friend. But one need not go far north to find the favourite spots for the Skylark’s broods: the next department, the Drôme, is rich in his nests. It is very probable therefore that, out of the numbers of Skylarks that come to take possession of our plains for the whole of autumn and winter, there are many that travel no farther than the Drôme. They have only to migrate to the next department to find plains free from snow and a steady supply of tiny seeds. A like migration to a short distance seems to me to have caused the crowd of Ammophilæ which I surprised near the top of Mont Ventoux. I have shown that this Wasp spends the winter in the perfect insect state, hidden in some shelter and waiting until April to make her nest. She also, like the Skylark, must take her precautions against the frosty season. Though she need not fear the lack of food, being capable of fasting until the return of the flowers, she must at least, delicate creature that she is, guard against the fatal attacks of the cold. She will therefore flee snowy country, the districts where the ground freezes to a great depth; she will assemble in a migratory caravan, after the manner of the birds, and, crossing hill and dale, will select a home in old walls and [228]sandy banks warmed by the southern sun. Then, when the cold is past, all or part of the troop will return to the place whence they came. This would explain the Ventoux band of Ammophilæ. It was a travelling tribe which, coming from the cold uplands of the Drôme and descending into the warm plains beloved of the olive-tree, had crossed the wide, deep valley of the Toulourenc and, when surprised by the rain, had called a halt on the mountain-ridge. Apparently, therefore, the Hairy Ammophila has to migrate in order to escape the cold of winter. At the time when the little birds of passage start their procession of caravans, she too journeys from a colder to a warmer neighbourhood. She has but to cross a few valleys and a few mountains to find the climate which she wants.

I have two other instances of extraordinary gatherings of insects at great heights. In October I have found the chapel at the summit of Mont Ventoux covered with Coccinella septempunctata, the Seven-spot Ladybird. The insects clinging to the stone of both the roof and walls were packed so close together that the rude edifice looked, from a little way off, like a piece of coral-work. I should not care to guess the myriad numbers of the Ladybirds collected there. Those Aphis-eaters had certainly not been attracted by the hope of food to the top of the Ventoux, some 6000 feet above the level of the sea. Vegetation is too scanty up there; and no Plant-louse ever ventured so high.

On another occasion, in June, on the tableland of Saint-Amans, a neighbour of the Ventoux, at a height of 2400 feet, I witnessed a similar gathering, only much less numerous. At the most prominent part of the plateau, on the edge of a bluff of perpendicular rocks, stands a cross with a pedestal of hewn stone. On each face of this pedestal and on the rocks supporting it, the same Beetles, the Seven-spot Ladybirds of the Ventoux, had gathered in their legions. The insects were mostly stationary; but, wherever the sun beat at all fiercely, there was a continual exchange between the newcomers, anxious to find room, and the old occupants of the wayside cross, who took to their wings only to return after a short flight.

Nothing here, any more than on the summit of the Ventoux, was able to tell me the cause of these strange meetings on arid spots, containing no Plant-lice and possessing no attraction for Ladybirds; nothing suggested the secret of these crowded gatherings on masonry situated at a great height. Were these again instances of entomological migration? Were they general musterings, similar to that of the Swallows on the day before their common departure? Were they meeting-places whence the swarm of Ladybirds was to make for some district richer in edibles? It is possible, but it is also very extraordinary. The Ladybird has rarely been noted as a devotee of travel. She seems to us a very stay-at-home creature when we see her butchering the Green-fly on our rose-trees and the Black-fly on our beans; and yet, with her short wings, she holds plenary assemblies, in immense numbers, on the summit of Mont Ventoux, where the Martin himself ascends only at moments of violent energy. Why these meetings at such altitudes? What can be the reason of this predilection for blocks of masonry?