THE DARK DAYS OF INSECT LIFE
Sometimes by too close and confining study of things pertaining to the genus Homo, we perchance find ourselves complacently wondering if we have not solved almost all the problems of this little whirling sphere of water and earth. Our minds turn to the ultra questions of atoms and ions and rays and our eyes strain restlessly upward toward our nearest planet neighbour, in half admission that we must soon take up the study of Mars from sheer lack of earthly conquest.
If so minded, hie you to the nearest grove and, digging down through the mid-winter’s snow, bring home a spadeful of leaf-mould. Examine it carefully with hand-lens and microscope, and then prophesy what warmth and light will bring forth. “Watch the unfolding life of plant and animal, and then come from your planet-yearning back to earth, with a humbleness born of a realisation of our vast ignorance of the commonest things about us.”
Though the immediate mysteries of the seed and the egg baffle us, yet the most casual lover of God’s out-of-doors may hopefully attempt to solve the question of some of the winter homes of insects. Think of the thousands upon thousands of eggs and pupæ which are hidden in every grove; what catacombs of bug mummies yonder log conceals,—mummies whose resurrection will be brought about by the alchemy of thawing sunbeams. Follow out the suggestion hinted at above and place a handkerchief full of frozen mould or decayed wood in a white dish, and the tiny universe which will gradually unfold before you will provide many hours of interest. But remember your responsibilities in so doing, and do not let the tiny plant germs languish and die for want of water, or the feeble, newly-hatched insects perish from cold or lack a bit of scraped meat.
Cocoons are another never-ending source of delight. If you think that there are no unsolved problems of the commonest insect life around us, say why it is that the moths and millers pass the winter wrapped in swaddling clothes of densest textures, roll upon roll of silken coverlets; while our delicate butterflies hang uncovered, suspended only by a single loop of silk, exposed to the cold blast of every northern gale? Why do the caterpillars of our giant moths—the mythologically named Cecropia, Polyphemus, Luna, and Prometheus—show such individuality in the position which they choose for their temporary shrouds? Protection and concealment are the watchwords held to in each case, but how differently they are achieved!
Cecropia—that beauty whose wings, fully six inches across, will flap gracefully through the summer twilight—weaves about himself a half oval mound, along some stem or tree-trunk, and becomes a mere excrescence—the veriest unedible thing a bird may spy. Polyphemus wraps miles of finest silk about his green worm-form (how, even though we watch him do it, we can only guess); weaving in all the surrounding leaves he can reach. This, of course, before the frosts come, but when the leaves at last shrivel, loosen, and their petioles break, it is merely a larger brown nut than usual that falls to the ground, the kernel of which will sprout next June and blossom into the big moth of delicate fawn tints, feathery horned, with those strange isinglass windows in his hind wings.
Luna—the weird, beautiful moon-moth, whose pale green hues and long graceful streamers make us realise how much beauty we miss if we neglect the night life of summer—when clad in her temporary shroud of silk, sometimes falls to the ground, or again the cocoon remains in the tree or bush where it was spun.
But Prometheus, the smallest of the quartet, has a way all his own. The elongated cocoon, looking like a silken finger, is woven about a leaf of sassafras. Even the long stem of the leaf is silk-girdled, and a strong band is looped about the twig to which the leaf is attached. Here, when all the leaves fall, he hangs, the plaything of every breeze, attracting the attention of all the hungry birds. But little does Prometheus care. Sparrows may hover about him and peck in vain; chickadees may clutch the dangling finger and pound with all their tiny might. Prometheus is “bound,” indeed, and merely swings the faster, up and down, from side to side.
It is interesting to note that when two Prometheus cocoons, fastened upon their twigs, were suspended in a large cageful of native birds, it took a healthy chickadee just three days of hard pounding and unravelling to force a way through the silken envelopes to the chrysalids within. Such long continued and persistent labour for so comparatively small a morsel of food would not be profitable or even possible out-of-doors in winter. The bird would starve to death while forcing its way through the protecting silk.
These are only four of the many hundreds of cocoons, from the silken shrouds on the topmost branches to the jugnecked chrysalis of a sphinx moth—offering us the riddle of a winter’s shelter buried in the cold, dark earth.
Is everything frozen tight? Has Nature’s frost mortar cemented every stone in its bed? Then cut off the solid cups of the pitcher plants, and see what insects formed the last meal of these strange growths,—ants, flies, bugs, encased in ice like the fossil insects caught in the amber sap which flowed so many thousands of years ago.
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When the fierce northwestern blast
Cools sea and land so far and fast,
Thou already slumberest deep;
Woe and want thou canst outsleep. Emerson. |