Chapter XIII Structures of Grasshoppers, Crickets, and Beetles
Grasshoppers, locusts, crickets, and beetles are, in many respects, no less interesting than the insects whose architectural proceedings we have already detailed. They do not, indeed, build any edifice for the accommodation of themselves or their progeny; but most, if not all of them, excavate retreats in walls or in the ground.
The house-cricket (Acheta domestica) is well known for its habit of picking out the mortar of ovens and kitchen fire-places, where it not only enjoys warmth, but can procure abundance of food. It is usually supposed that it feeds on bread. M. Latreille says it only eats insects, and it certainly thrives well in houses infested by the cockroach; but we have also known it eat and destroy lamb’s-wool stockings, and other woolen stuffs, hung near a fire to dry. It is evidently not fond of hard labour, but prefers those places where the mortar is already loosened, or at least is new, soft, and easily scooped out; and in this way it will dig covert ways from room to room. In summer, crickets often make excursions from the house to the neighbouring fields, and dwell in the crevices of rubbish, or the cracks made in the ground by dry weather, where they chirp as merrily as in the snuggest chimney-corner. Whether they ever dig retreats in such circumstances we have not ascertained: though it is not improbable they may do so for the purpose of making nests. M. Bory St. Vincent tells us that the Spaniards are so fond of crickets that they keep them in cages like singing birds.CC
The insect, called, from its similarity of habits to the mole, the mole-cricket (Gryllotalpa vulgaris, Latr.), is but too well known in gardens, corn-fields, and the moist banks of rivers and ponds, in some parts of England, such as Wiltshire and Hampshire, though it is comparatively rare or unknown in others. It burrows in the ground, and forms extensive galleries similar to those of the mole, though smaller; and these may always be recognized by a slightly elevated ridge of mould: for the insect does not throw up the earth in hillocks like the mole, but gradually, as it digs along, in the manner of the field-mouse. In this way it commits great ravages, in hotbeds and in gardens, upon peas, young cabbages, and other vegetables, the roots of which it is said to devour. It is not improbable, we think, that, like its congener, the house-cricket, it may also prey upon underground insects, and undermine the plants to get at them, as the mole has been proved to do. Mr Gould, indeed, fed a mole-cricket for several months upon ants.
The structure of the mole-cricket’s arms and hands (if we may call them so) is admirably adapted for these operations, being both very strong, and moved by a peculiar apparatus of muscles. The breast is formed of a thick, hard, horny substance, which is further strengthened within by a double framework of strong gristle, in front of the extremities of which the shoulder-blades of the arms are firmly jointed: a structure evidently intended to prevent the breast from being injured by the powerful action of the muscles of the arms in digging. The arms themselves are strong and broad, and the hand is furnished with four large sharp claws, pointed somewhat obliquely outwards, this being the direction in which it digs, throwing the earth on each side of its course. So strongly indeed does it throw out its arms, that we find it can thus easily support its own weight when held between the finger and thumb, as we have tried upon half-a-dozen of the living insects now in our possession.
The nest which the female constructs for her eggs, in the beginning of May, is well worthy of attention. The Rev. Mr. White, of Selborne, tells us that a gardener, at a house where he was on a visit, while mowing grass by the side of a canal, chanced to strike his scythe too deep, and pared off a large piece of turf, laying open to view an interesting scene of domestic economy. There was a pretty chamber dug in the clay, of the form and about the dimensions it would have had if moulded by an egg, the walls being neatly smoothed and polished. In this little cell were deposited about a hundred eggs, of the size and form of caraway comfits, and of a dull tarnished white colour. The eggs were not very deep, but just under a little heap of fresh mould, and within the influence of the sun’s heat.CD The dull tarnished white colour, however, scarcely agrees with a parcel of these eggs now before us, which are translucent, gelatinous, and greenish.
Like the eggs and young of other insects, however, those of the mole-cricket are exposed to depredation, and particularly to the ravages of a black beetle which burrows in similar localities. The mother insect, accordingly, does not think her nest secure till she has defended it, like a fortified town, with labyrinths, intrenchments, ramparts, and covert ways. In some part of these out-works she stations herself as an advanced guard, and when the beetle ventures within her circumvallations, she pounces upon him and kills him.
The Field-Cricket.
Another insect of this family, the field-cricket (Acheta campestris), also forms burrows in the ground, in which it lodges all day, and comes out chiefly about sunset to pipe its evening song. It is so very shy and cautious, however, that it is by no means easy to discover either the insect or its burrow. “The children in France amuse themselves with hunting after the field-cricket; they put into its hole an ant fastened by a long hair, and as they draw it out the cricket does not fail to pursue it, and issue from its retreat. Pliny informs us it might be captured in a much more expeditious and easy manner. If, for instance, a small and slender piece of stick were to be thrust into the burrow, the insect, he says, would immediately get upon it for the purpose of demanding the occasion of the intrusion: whence arose the proverb, stultior grillo (more foolish than a cricket), applied to one who, upon light grounds, provokes his enemy, and falls into the snares which might have been laid to entrap him.”CE
The Rev. Mr. White, who attentively studied their habits and manners, at first made an attempt to dig them out with a spade, but without any great success; for either the bottom of the hole was inaccessible, from its terminating under a large stone, or else in breaking up the ground the poor creature was inadvertently squeezed to death. Out of one thus bruised a great number of eggs were taken, which were long and narrow, of a yellow colour, and covered with a very tough skin. More gentle means were then used, and these proved successful. A pliant stalk of grass, gently insinuated into the caverns, will probe their windings to the bottom, and bring out the inhabitant; and thus the humane inquirer may gratify his curiosity without injuring the object of it.
When the males meet, they sometimes fight very fiercely, as Mr. White found by some that he put into the crevices of a dry stone wall, where he wished to have them settle. For though they seemed distressed by being taken out of their knowledge, yet the first that got possession of the chinks seized on all the others that were obtruded upon him with his large row of serrated fangs. With their strong jaws, toothed like the shears of a lobster’s claws, they perforate and round their curious regular cells, having no fore-claws to dig with, like the mole-cricket. When taken into the hand, they never attempt to defend themselves, though armed with such formidable weapons. Of such herbs as grow about the mouths of their burrows they eat indiscriminately, and never in the day-time seem to stir more than two or three inches from home. Sitting in the entrance of their caverns, they chirp all night as well as day, from the middle of the month of May to the middle of July. In hot weather, when they are most vigorous, they make the hills echo; and, in the more still hours of darkness, may be heard to a very considerable distance. “Not many summers ago,” says Mr. White, “I endeavoured to transplant a colony of these insects to the terrace in my garden, by boring deep holes in the sloping turf. The new inhabitants stayed some time, and fed and sang; but they wandered away by degrees, and were heard at a greater distance every morning; so it appears that on this emergency they made use of their wings in attempting to return to the spot from which they were taken.”CF The manner in which these insects lay their eggs is represented in the following figure, which is that of an insect nearly allied to the crickets, though of a different genus.
A more laborious task is performed by an insect by no means uncommon in Britain, the burying beetle (Necrophorus vespillo), which may be easily recognized by its longish body, of a black colour, with two broad and irregularly indented bands of yellowish brown. A foreign naturalist, M. Gleditsch, gives a very interesting account of its industry. He had “often remarked that dead moles, when laid upon the ground, especially if upon loose earth, were almost sure to disappear in the course of two or three days, often of twelve hours. To ascertain the cause, he placed a mole upon one of the beds in his garden. It had vanished by the third morning; and on digging where it had been laid, he found it buried to the depth of three inches, and under it four beetles, which seemed to have been the agents in this singular inhumation. Not perceiving anything particular in the mole, he buried it again; and on examining it at the end of six days, he found it swarming with maggots, apparently the issue of the beetles, which M. Gleditsch now naturally concluded had buried the carcase for the food of their future young. To determine these points more clearly, he put four of these insects into a glass vessel, half filled with earth and properly secured, and upon the surface of the earth two frogs. In less than twelve hours one of the frogs was interred by two of the beetles; the other two ran about the whole day, as if busied in measuring the dimensions of the remaining corpse, which on the third day was also found buried. He then introduced a dead linnet. A pair of the beetles were soon engaged upon the bird. They began their operations by pushing out the earth from under the body, so as to form a cavity for its reception; and it was curious to see the efforts which the beetles made, by dragging at the feathers of the bird from below, to pull it into its grave. The male, having driven the female away, continued the work alone for five hours. He lifted up the bird, changed its place, turned it, and arranged it in the grave, and from time to time came out of the hole, mounted upon it, and trod it under foot, and then retired below, and pulled it down. At length, apparently wearied with this uninterrupted labour, it came forth, and leaned its head upon the earth beside the bird, without the smallest motion, as if to rest itself, for a full hour, when it again crept under the earth. The next day, in the morning, the bird was an inch and a half under ground, and the trench remained open the whole day, the corpse seeming as if laid out upon a bier, surrounded with a rampart of mould. In the evening it had sunk half an inch lower, and in another day the work was completed, and the bird covered. M. Gleditsch continued to add other small dead animals, which were all sooner or later buried; and the result of his experiment was, that in fifty days four beetles had interred, in the very small space of earth allotted to them, twelve carcases, viz., four frogs, three small birds, two fishes, one mole, and two grasshoppers, besides the entrails of a fish, and two morsels of the lungs of an ox. In another experiment, a single beetle buried a mole, forty times its own bulk and weight, in two days.”CG
In the summer of 1826, we found on Putney Heath, in Surrey, four of these beetles, hard at work in burying a dead crow, precisely in the manner described by M. Gleditsch. (J. R.)
Dung-Beetle.
A still more common British insect, the dorr, clock, or dung-beetle (Geotrupes stercorarius), uses different materials for burying along with its eggs. “It digs,” to use the words of Kirby and Spence, “a deep cylindrical hole, and carrying down a mass of the dung to the bottom, in it deposits its eggs. And many of the species of the genus Ateuchus roll together wet dung into round pellets, deposit an egg in the midst of each, and when dry push them backwards, by their hind feet, to holes of the surprising depth of three feet, which they have previously dug for their reception, and which are often several yards distant. The attention of these insects to their eggs is so remarkable, that it was observed in the earliest ages, and is mentioned by ancient writers, but with the addition of many fables; as that they were all of the male sex; that they became young again every year; and that they rolled the pellets containing their eggs from sunrise to sunset every day, for twenty-eight days, without intermission.”CH
“We frequently notice in our evening walks,” says Mr. Knapp, “the murmuring passage, and are often stricken by the heedless flight of the great dorr-beetle (Geotrupes stercorarius), clocks, as the boys call them. But this evening my attention was called to them in particular, by the constant passing of such a number as to constitute something like a little stream; and I was led to search into the object of their direct flight, as in general it is irregular and seemingly inquisitive. I soon found that they dropped on some recent nuisance: but what powers of perception must these creatures possess, drawn from all distances and directions by the very little fetor which, in such a calm evening, could be diffused around, and by what inconceivable means could odours reach, this beetle in such a manner as to rouse so inert an insect into action! But it is appointed one of the great scavengers of the earth, and marvellously endowed with powers of sensation, and means of effecting this purpose of its being. Exquisitely fabricated as it is to receive impressions, yet probably it is not more highly gifted than any of the other innumerable creatures that wing their way around us, or creep about our paths, though by this one perceptible faculty, thus ‘dimly seen,’ it excites our wonder and surprise. How wondrous then the whole!
“The perfect cleanliness of these creatures is a very notable circumstance, when we consider that nearly their whole lives are passed in burrowing in the earth, and removing nuisances; yet such is the admirable polish of their coating and limbs, that we very seldom find any soil adhering to them. The meloe, and some of the scarabæi, upon first emerging from their winter’s retreat, are commonly found with earth clinging to them; but the removal of this is one of the first operations of the creature; and all the beetle race, the chief occupation of which is crawling about the soil, and such dirty employs, are, notwithstanding, remarkable for the glossiness of their covering, and freedom from defilements of any kind. But purity of vesture seems to be a principal precept of Nature, and observable throughout creation. Fishes, from the nature of the element in which they reside, can contract but little impurity. Birds are unceasingly attentive to neatness and lustration of their plumage. All the slug race, though covered with slimy matter calculated to collect extraneous things, and reptiles, are perfectly free from soil. The fur and hair of beasts, in a state of liberty and health, is never filthy or sullied with dirt. Some birds roll themselves in dust, and, occasionally, particular beasts cover themselves with mire; but this is not from any liking or inclination for such things, but to free themselves from annoyances, or to prevent the bites of insects. Whether birds in preening, and beasts in dressing themselves, be directed by any instinctive faculty, we know not; but they evidently derive pleasure from the operation, and thus this feeling of enjoyment, even if the sole motive, becomes to them an essential source of comfort and of health.”CI
The rose or green chafer (Cetonia aurata), which is one of our prettiest native insects, is one of the burrowers, and, for the purpose of depositing her eggs, digs, about the middle of June, into soft light ground. When she is seen at this operation, with her broad and delicate wings folded up in their shining green cases, speckled with white, it could hardly be imagined that she had but just descended from the air, or dropped down from some neighbouring rose.
The proceedings of the Tumble-Dung Beetle of America (Scarabæus pilularius, Linn.) are described in a very interesting manner by Catesby, in his ‘Carolina.’ “I have,” says he, “attentively admired their industry, and mutual assisting of each other in rolling their globular balls from the place where they made them to that of their interment, which is usually the distance of some yards, more or less. This they perform breech foremost, by raising their hind parts, and forcing along the ball with their hind feet. Two or three of them are sometimes engaged in trundling one ball, which, from meeting with impediments on account of the unevenness of the ground, is sometimes deserted by them. It is, however, attempted by others with success, unless it happens to roll into some deep hollow or chink, where they are constrained to leave it; but they continue their work by rolling off the next ball that comes in their way. None of them seem to know their own balls, but an equal care for the whole appears to affect all the community. They form these pellets while the dung remains moist, and leave them to harden in the sun before they attempt to roll them. In their moving of them from place to place, both they and the balls may frequently be seen tumbling about the little eminences that are in their way. They are not, however, easily discouraged; and, by repeating their attempts, usually surmount the difficulties.”
He further informs us that they “find out their subsistence by the excellency of their noses, which direct them in their flight to newly-fallen dung, on which they immediately go to work, tempering it with a proper mixture of earth. So intent are they always upon their employment, that, though handled or otherwise interrupted, they are not to be deterred, but immediately, on being freed, persist in their work without any apprehension of danger. They are said to be so exceedingly strong and active as to move about, with the greatest ease, things that are many times their own weight. Dr. Brichell was supping one evening in a planter’s house of North Carolina, when two of them were conveyed, without his knowledge, under the candlesticks. A few blows were struck on the table, and, to his great surprise, the candlesticks began to move about, apparently without any agency; and his surprise was not much lessened when, on taking one of them up, he discovered that it was only a chafer that moved it.”
We have often found the necklace-beetle (Carabus monilis) inhabiting a chamber dug out in the earth of a garden, just sufficient to contain its body, and carefully smoothed and polished. From the form of this little nest, it would seem as if it were constructed, not by digging out the earth and removing it, but chiefly by the insect pushing its body forcibly against the walls. The beetles which we have found nestling in this manner have been all males; and therefore it cannot be intended for a breeding-cell; for male insects are never, we believe, sufficiently generous to their mates to assist them in such labours. The beetle in question appears to be partial to celery trenches (J. R.); probably from the loose earth of which they are composed yielding, without much difficulty, to the pressure of its body.
[Many of the subterranean larvæ which are turned up by the spade or the plough are the imperfect conditions of earth-burrowing beetles, and many of them are among the most insidious pests of the farmer, their ravages being all the more dangerous because they are unseen.]
The most destructive, perhaps, of the creatures usually called grubs are the larvæ of the may-bug or cockchafer (Melolontha vulgaris), but too well known, particularly in the southern and midland districts of England, as well as in Ireland, where the grub is called the Connaught worm;CJ but fortunately not abundant in the north. We only once met with the cockchafer in Scotland, at Sorn, in Ayrshire. (J. R.) Even in the perfect state, this insect is not a little destructive to the leaves of both forest and fruit trees. In 1823, we remember to have observed almost all the trees about Dulwich and Camberwell defoliated by them; and Salisbury says, the leaves of the oaks in Richmond Park were so eaten by them, that scarcely an entire leaf was left. But it is in their previous larva state that they are most destructive, as we shall see by tracing their history.
The mother cockchafer, when about to lay her eggs, digs into the earth of a meadow or corn-field to the depth of a span, and deposits them in a cluster at the bottom of the excavation. Rösel, in order to watch the proceedings, put some females into glasses half-filled with earth, covered with a tuft of grass and a piece of thin muslin. In a fortnight, he found some hundreds of eggs deposited, of an oval shape and a pale-yellow colour. Placing the glass in a cellar, the eggs were hatched towards autumn, and the grubs increased remarkably in size. In the following May they fed so voraciously that they required a fresh turf every second day; and even this proving too scanty provender, he sowed in several garden pots a crop of peas, lentils, and salad, and when the plants came up he put a pair of grubs in each pot; and in this manner he fed them through the second and third years. During this period, they cast their skins three or four times, going for this purpose deeper into the earth, and burrowing out a hole where they might effect their change undisturbed; and they do the same in winter, during which they become torpid and do not eat.
When the grub changes into a pupa, in the third autumn after it is hatched, it digs a similar burrow about a yard deep; and when kept in a pot, and prevented from going deep enough, it shows great uneasiness and often dies. The perfect beetle comes forth from the pupa in January or February; but it is then as soft as it was whilst still a grub, and does not acquire its hardness and colour for ten or twelve days, nor does it venture above ground before May, in the fourth year from the time of its hatching. At this time, the beetles may be observed issuing from their holes in the evening, and dashing themselves about in the air as if blind.
During the three summers then of their existence in the grub state, these insects do immense injury, burrowing between the turf and the soil, and devouring the roots of grass and other plants; so that the turf may easily be rolled off, as if cut by a turfing spade, while the soil underneath for an inch or more is turned into soft mould like the bed of a garden. Mr. Anderson, of Norwich, mentions having seen a whole field of fine flourishing grass so undermined by these grubs, that in a few weeks it became as dry, brittle, and withered as hay.CK Bingley also tells us that “about sixty years ago, a farm near Norwich was so infested with cockchafers, that the farmer and his servants affirmed they gathered eighty bushels of them; and the grubs had done so much injury, that the court of the city, in compassion to the poor fellow’s misfortune, allowed him twenty-five pounds.”CL In the year 1785, a farmer, near Blois, in France, employed a number of children and poor persons to destroy the cockchafers at the rate of two liards a hundred, and in a few days they collected fourteen thousand.CM
“I remember,” says Salisbury, “seeing in a nursery near Bagshot, several acres of young forest trees, particularly larch, the roots of which were completely destroyed by it, so much so that not a single tree was left alive.”CN We are doubtful, however, whether this was the grub of the cockchafer, and think it more likely to have been that of the green rose-beetle (Cetonia aurata), which feeds on the roots of trees.