Part 12
But when the days have grown longer and warmer, and the trees are arrayed in their livery of green, she is in the fields bright and early, and often ere the dew has disappeared from the grass and the flowers. The most restless of beings she now is. Anon alighting upon a bush for a momentary rest, then off for a dozen or more rods, when the presence of some favorite blossom meets her quick sight and invites her to pause, which she does, but only for a second to quench her thirst. Where willows, or elms, or poplars abound, she is more frequently seen later on in May, but flying more slowly and sedately than ever before. The flowers pass unheeded. She seems in a dream, in a reverie. But all of a sudden she quickens her speed. You look for the cause. There, in the distance, another is seen, just like her in mien, some would-be suitor for her hand and affections. He enters his suit, he pleads his great love, and awaits her sweet pleasure. The answer is brief, and soon by their actions, as high up in the air they circle and circle, caressing each other with strokes of the antennæ, the story is told that his love has been requited. A brief honey-moon of two or three days and the love-scene is over, and the two settle down to the prosy realities of everyday life. The male goes back to his old-time pursuit of rifling the flowers of their honeyed treasures, whilst the female, upon whom devolves the duty of providing for the offspring whom she is never likely to see, looks scrutinizingly about for her favorite trees, the poplar, the elm, or the willow. In her selection of a tree a wonderfully keen discernment is shown, for she seldom, if ever, mistakes her plant-species.
When a choice has been made, no time is expended in fruitless endeavor. She proceeds at once to deposit her eggs. They are laid in a cluster round the twig, and near the petiole of a young leaf, upon which the newly-hatched larvæ are to feed. The eggs hatch inside of a week into small black spiny caterpillars which, in their early stages, are very social in their habits. Just before the final skin-moulting they separate, each caterpillar living alone, the necessity for food, which their very vigorous appetites now demand, being the impelling motive. In a state of maturity the larvæ are two inches in length. They are black, and minutely dotted with white, which gives them a greyish look. A row of brick-red spots are found down the back, and their body is armed with many black, rather long and slightly branching spines. The head is black, and roughened with small black tubercles.
Having completed their period of feeding, which they do in about four weeks, the caterpillars attach themselves by means of their tails to a fence-rail, a window-ledge, or some such place, and pass into the chrysalis state, which is accomplished in about four days. In this condition they present an odd-looking appearance. The head will be found to be deeply notched, or furnished with two ear-like prominences. The sides are very angular. In the middle of the thorax there is a thin projection, somewhat like a Roman nose in profile, while on the back are two rows of very sharp tubercles of a tawny color, which contrast very markedly in coloration with the dark-brown of the rest of the chrysalis. Fifteen days, when the weather is favorable, are sufficient for the development of the imago, or butterfly. As maturity approaches, the chrysalis-shell becomes quite soft, and the efforts of the imago to free itself from this covering are facilitated by the ejection of a blood-red fluid, which rots the case, while it acts, at the same time, as a lubricant to the emerging butterfly.
When these caterpillars are very abundant, as was the case in the vicinity of Germantown some twenty-five years ago, every fence-rail was hung with chrysalids, as many as a dozen being found upon a single rail. The caterpillars even climbed up the sides of the houses and suspended themselves from the window-ledges and the edges of the overhanging shingles. When the butterflies emerged, great blotches of the fluid bespattered the fences and houses as though the clouds had rained great drops of blood. The willows and poplars were alive with the caterpillars, and even the maples were overrun when there came a scarcity of the leaves of the natural food-plants. Green caterpillar-hunters were everywhere plentiful, and the writer could have taken hundreds of specimens, but these highly-useful beetles made a very sorry attempt in holding the enemy in check.
Two broods of the caterpillars are raised, one in June and the other in August, but the agencies by nature employed for their destruction so effectually accomplish their mission that hardly a season brings to my notice a dozen full-grown larvæ. _Vanessa antiopa_, as this species is called by the scientific student, or Mourning-Cloak by people and amateurs, is generally found through the whole of North America. In England, where it is popularly called the Camberwell Beauty, because specimens were first taken near Camberwell, it is the rarest of butterflies; while on the Continent, as in this country, it is a very plentiful insect.
LEAF-CUTTER BEE.
Few hymenoptera of the family of bees are so little known as the Megachilidæ, or Leaf-cutters. They are stout, thick-bodied insects, with large, square heads, and armed with sharp, scissors-like jaws, which admirably fit them for the work they have to do in preparing materials for the building of their homes.
Our commonest species, _Megachile centuncularis_, is about the size of the hive-bee. In gardens and nurseries where shrubbery abounds, it is very prevalent, especially the female, which is readily distinguished by a thick mass of stout, dense hair on the under side of the tail, which serves as a carrier of pollen. The honey- and bumble-bees differ materially from them, for they have the hind tibiæ and basal joints of the tarsi very much broadened for that purpose.
Megachile is by no means a remarkable-looking insect. Judging from its very humble exterior, one can hardly believe it possessed of the wonderful intelligence, as shown in its wise provisions for its young, which it is found to display.
Ordinarily the female, who is entrusted with the discharge of this very essential business, places her nest in the solid earth underneath some species of shrub. A vertical hole, three inches in depth, is dug, and this is enlarged into a horizontal gallery, some five or six inches in length.
You should see the little creature in her never-tiring work of preparing material for her nest. In and out among the roses she goes, examining each leaf with the most critical care, and only desisting from her labor when a suitable one has been chosen. She scans it over and over, and at last from a position on its upper or nether surface proceeds to cut a piece just fitted for her work, which, heavy as it seems, is seized between the legs and jaws and carried on swiftly-agitated wings to her burrow.
Ten pieces or more, each differing in shape, are cut and borne away, which the ingenious insect tailor twists and folds, the one within the other, until is formed a funnel-like cone, whose end is narrower than its mouth. So perfectly joined are the parts, that even when dry they have been found to retain their form and integrity. A cake of honey and pollen, for the use of some yet unborn Leaf-cutter, is deposited within, and on this, in due time, is laid a single small egg. Nought now remains but to wall up the cell. A circle of leaf, of the size of the opening, is cut, and this is closely adjusted within the wall of rolled-up leaves. Sometimes as many as four pieces are thus utilized. A second cell, similarly built, is fitted to the first, and this is succeeded by eight or ten others. When all is completed, the eggs being laid and the cells all victualled, the hole of the shaft is closed with the earth that was thrown out, and so carefully, too, that not a trace of her doings remains to tell us the story.
Like other insects, Megachile is occasionally prone to change. Some laborers while digging, one early spring-day, some thirteen years ago, about a cluster of plants of _Spiræa corymbosa_, a species allied to the roses and cinquefoils, came unexpectedly upon a dozen or more cells of this insect, arranged horizontally in layers, some three or four inches below the ground’s surface. These cells were three-fourths of an inch in length, one-fourth in width, and formed of the leaves of Spiræa. Six circles, of three pieces each, constituted the cell, and these were so arranged that each succeeding circle was made to project but slightly beyond its predecessor. Six circular pieces, larger than seemed needful, closed up the opening of each cell. That there was a purpose here manifested was very apparent. This purpose, as it appeared to the writer, was the better accommodation by the hollow surface of the cell that was to follow, and the giving of greater firmness and security to the entire structure.
More curious, however, were some cells that were found the ensuing year, which, in looks, resembled very closely those of Pelopæus, a species of wasp, familiarly designated the Mud-dauber. These cells, in numbers of three, were adherent to the rafters of a hardly-used garret. In form, and in the peculiar combination of their pellets of clay, they were the exact counterpart of the Mud-dauber’s. But the curious funnel-like arrangement of leaves on the inside, so strikingly characteristic of the Megachilidæ, was evidence of the most positive kind that Pelopæus had nothing whatever to do with their putting together. It bespoke a piece of work that was entirely beyond the highest capability of her being to execute.
Each of the included leafy cells was one and one-eighth inches in length, and just barely exceeding one-fourth in width. Elliptical pieces of Spiræa, less in size than those previously described, but arranged in a similar manner, composed the several structures. Within each, a dead but perfectly-formed Megachile, encased in a cylindrical bag of silk, was found, so that there could be no possible doubt of the builder. That this inner fabric was the labor of some mother Megachile admits not of a scruple, for no other bee is known to construct a nest of like character. But what of the outer enveloping fabric of mud? It was clearly impossible for the skill of a Megachile, who, while certainly fitted for tunnelling the ground and for snipping circular and elliptical pieces of suited dimensions from leaves with all a tailor’s precision, would find herself wofully unadapted for the making of mortar and the building of nests, in imitations of tunnels, out of pellets of mud that had to be moulded into consistency and shape by the jaws of the builder. Pelopæus alone, of all hymenopters, possesses the ability and means of making such structures. Megachile, who is known to occasionally build under the boards of the roof of a piazza, might sometimes in her quest of a place appropriate the discarded cells of some pre-existent Pelopæus for nesting purposes, but she runs a very great risk in so doing, for the Mud-dauber does not always build a fresh home for her treasures, save when there is a lack of the last year’s structures. Old nests, when found, are put in speedy repair and made to do as invaluable a service.
BATTLE BETWEEN ANTS.
Whilst reclining one beautiful May afternoon in the shade of an oak that stood on the outskirts of a thicket, my attention was arrested by the activity and bustle presented by a colony of yellow ants, which proved to be the _Formica flava_, so common everywhere.
Scattered indiscriminately about were numberless larvæ in various stages of growth, and not a few immobile pupæ, that had been brought up from subterranean domiciles by thoughtful nurses, while here and there were a dozen or more ants, but recently escaped from their mummy-cases, basking in the sun’s warmth, preparatory to entering upon the duties of the formicarium.
The very picture of restlessness and anxiety were these full-grown neuters. That something was transpiring, or was about to transpire, seemed not unlikely, for ovæ, larvæ and pupæ were being quickly carried to places of concealment in the earth, or hustled away among the entangling and interlacing grasses.
Looking about for the cause of all this excitement, the truth at once became painfully apparent. Three large, burly ants, representatives of _Formica subterranea_, a black species that is everywhere abundant in wooded regions, had intruded their obnoxious presence into the happy colony, bent, as it was evident, on pillage or slaughter.
Were plunder the inspiring motive, these giant invaders were not slow to learn that their weaker kin, though lacking their strength, could more than match them in cunning and stratagem.
Not daring to attack the foe, and being unwilling that any of their number should be led into slavery, or suffer aught at the hands of others, they immediately set to work to destroy all whom it was impossible to protect.
Detailed as most of the neuters seemed to be in looking after the wants of the immature, there were a few observed running hither and thither and seizing in their jaws the newly-developed, not to bear them out of the reach of danger, as was at first supposed, but to kill them so as to prevent them from falling a living prey into the hands of the enemy.
Knowing the sympathy and affection which the nurses are ever wont to cherish towards the objects of their care, this act of cruelty struck me as something very astonishing and peculiar.
Prompted by curiosity to know the nature of the wounds thus inflicted, I placed upon the palm of my hand one of the wounded ants, and made, by means of a microscope, a careful examination of its injuries. Above and below the abdomen, between the second and third segments, two deep wounds, which met each other in the interior, were plainly to be seen.
Several cases of the kind were afterwards noticed. These were not accidental occurrences, made through efforts to carry the young to places of shelter. Possibly, through inexperience, accidents might happen once in a long time, but to suppose that insects, accustomed to handling their young as the neuters assuredly are, would be likely to make such blunders, is too unreasonable to be entertained. Admitting for argument’s sake that such things might occasionally occur, would successive repetitions be expected? I apprehend not. But on the supposition that a purpose was thereby subserved, the object had in view warrants, it would seem, the means employed for its accomplishment.
What the purpose was it will now be my aim to show. That many animals, tame as well as wild, are wont to destroy disabled and wounded companions, is well established by history. In many instances the destruction is justified to preserve the herd or pack from the close pursuit of enemies. “Instinct or reason,” as Darwin says, “may suggest the expelling an injured companion, lest beasts of prey, including man, should be tempted to follow the troop.”
Audubon, in writing of the wild turkey, so abundant in his day, observes substantially that the old males in their marches often destroy the young by picking the head, but do not venture to disturb the full-grown and vigorous. The feeble and immature being an encumbrance, it is obvious that the watchfulness and attention which they would require, were sympathy and affection the emotions by which the males are actuated, would necessarily retard progress, and lead to the destruction of the entire flock. Instinct or reason here operates for individual and family good.
Granting that instinct or reason does sometimes act for individual and family preservation in the manner described, I am not willing to admit that in every case that may arise in which the weak and disabled are sacrificed, that it is done for the material benefit of the physically able and robust. How the destruction of the weak and nearly-developed ant can result in good to the colony, in view of the fact that not the slightest effort to escape the danger by flight is undertaken, the sole object being the hiding of the young, it is most difficult to conceive.
There seems to be one of two theories, in the writer’s judgment, that will, in anything like a satisfactory manner, account for this strange, abnormal habit upon the part of an insect that has been proverbially distinguished for its kind and affectionate disposition towards the tender beings committed to its trust; either to attribute it to an unwillingness and dislike to see its offspring made the servants of a hostile race or the subjects of ill-treatment and abuse, or to the survival of a habit of the past when its ancestors were a migratory, or nomadic, species.
That a feeling of repugnance does sometimes take possession of animal nature when the objects of parental care and solicitude are, or are about to be, reduced to slavery or confinement, and impels to actions of cruelty, will be patent from what follows:--
A friend, several summers ago, having procured a pair of young robins, placed them in a cage, which he hung from a tree-branch close to his dwelling, where the parent-birds could have an opportunity to feed them. All went well for a few days, when the parents, who had busied themselves in the intervals of feeding in attempts to secure their release, finding their efforts unavailing, flew away, but only to return with something green in their bills, most probably poisonous caterpillars, which they fed to their offspring. A few minutes later and they lay in the bottom of the cage dead, but the parents, as if conscious of what would result, flew away, and never came back.
May it not be that the parents, finding all efforts to restore their young to freedom ineffectual, sought this method of saving them from a life to which death must assuredly be preferable? Instances of like character might be adduced by the hundred, but enough has been written to show that, in the case of _Formica flava_, an unwillingness to allow the humblest of the colony to be taken into bondage was the motive which prompted the sacrifice.
NEST-BUILDING FISHES.
Not alone in color do fishes resemble birds. In the home-life and love of offspring a close resemblance obtains. Many are nest-builders, erecting structures quite as complicated as those of some birds, and hardly less elaborate in design and finish.
Floating along some woodland stream, or strolling along its grass-fringed margin, we have watched the domestic life of the Sun-fish, the _Eupomotis vulgaris_ of writers, that mottled, bespangled beauty that seems always on hand to be caught by the angler in default of more noble game.
Where delicate grasses grow, and floating lily-pads cast their shadows, there among the winding stems the Sun-fish builds its home. Moving in pairs in and out among the lilies near the shore, as if jointly selecting a site for a nursery, they may be seen. The spot is generally a gravelly one, and, once determined upon, no time is lost in pushing the work to a speedy conclusion. For several inches around the space is cleared of stems or roots, and these are carefully carried away. The smaller roots are swept aside by well-directed blows of their tails, or by mimic whirlpools which the fishes, standing over the nest, create by their fins. The stones are next taken up, the smaller ones in their mouths, the larger being pushed out bodily, or fanned away by the sweeping process, until an oval depression, with a sandy bottom, finally appears. About the sides the stems of aquatic verdure, which seem to have been purposely left, may be seen standing, and these now naturally fall over, oftentimes constituting the nest a perfect bower, with walls bedecked with buds, while the roof is a mat of white lilies floating upon the surface. Here the eggs are deposited, the male and female alternately watching them.
While the Sun-fish is always recognized as the most peaceful of the finny tribe, and only chasing in wanton playfulness its neighbors, it is otherwise when the passions are wrought to a high pitch of excitement through the play of amatory influences in the spring-time. Let a stranger, a bewhiskered cat-fish, approach the bower, and war is at once declared. The little creatures snap at the intruder with anger and defiance. Their sharp dorsal fins stand erect, the pectorals vibrate with repressed emotion, while the violent movements of their powerful tails evince a readiness and determination to stand by their home at all hazards. Indeed, so vigorous is their charge, that even large fishes are forced to retreat, and, as the Sun-fishes build in companies, the intruder often finds himself attacked by a whole colony of them.
Nearly all the Sun-fishes are nest-builders, some forming arbors, as we have seen, others scooping out nests on sandy shoals, while one, the Spotted Sun-fish, is more democratic, affecting muddy streams, where, on the approach of cold weather, it makes a nest in the muddy bottom, and there it lies dormant till the coming spring.
Who has not made friends with the Dace--_Rhinichthys atronasus_? He is a veritable finny jester. We have watched him in his watery retreat, and, perhaps unseen, have played the spy upon his domestic proceedings.
Life is a gala time to these little fishes. They have seemingly never a care or a bother. In jest they join in the chase of some curious minnow that intrudes upon their presence, suddenly changing their course to dash at some resplendent dragon-fly that hovers over the leafy canopy of their home, and as quickly darting off again to attack some bit of floating leaf or imaginary insect.
All is not play, however, even among the Dace. The warm days of June usher in the sterner duties, the nesting-time. Male and female join in the preparation, and a locality, perhaps in shallow water in some running brook, is selected. Roots, snags and leaves are carried away, both fishes sometimes found tugging away at a single piece, taking it down-stream, and working faithfully and vigorously until, in a few hours, a clearing over two feet in diameter is the result.
There the first eggs are laid. The male, who has retired, soon appears from up-stream, bearing in his mouth a pebble, which is placed in the centre of the clearing. Now they both swim away, but soon returning, each bearing a pebble, that is also dropped upon the eggs. Slowly the work proceeds, until a layer of clean pebbles apparently covers the eggs. A second layer of eggs is now deposited by the female, and these are covered by pebbles as the others had been, the industrious little workers scouring the neighborhood for them, seemingly piling up eggs and stones alternately until the heap attains a height of eight inches or more. These heaps vary in shape, some being pyramidal, and others dome-shaped.