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The New Zealand Railways Magazine, Volume 5, Issue 5 (September 1, 1930)

Glimpses Into Nature's Treasure Trove

page 62

Glimpses Into Nature's Treasure Trove

Nature is limitless in delight, stupendous in intensity! Marvel upon marvel unfolds itself. What is apparently perfection is everlastingly being improved upon to meet the exigencies of living and survival. “Mimicry” in its two forms, “protective” and “aggressive,” are beyond wonder; the result of centuries of evolution.

New Zealand, comparatively, furnishes few instances of “mimicry,” but in more tropical countries this form is most abundant. Our “stick insect” (Acanthoderus horridus) and “leaf insect” (Xiphidium maoricum) are both perfect examples. The former is more generally known than the latter; which is not only remarkably timid, but also exactly like a green leaf when quiescent. The insect's presence is advertised by a peculiar chirping note, produced by rubbing the wing cases together, sharply; but, to see or to catch it is quite another and difficult problem, for it becomes silent, motionless and invisible on being approached.

The leaf butterfly of Queensland, Australia, and many other countries, is another magnificent mimic. A flash of vivid colour arrests the eye, then … it has mysteriously vanished! Some instinct of danger has warned the insect, and it has sought sanctuary—a bush covered in dry leaves. Keen eyes indeed will be necessary to discover it …. the bush may be violently shaken, but without any result. The wings, vividly coloured on the upper surface, are, when closed, exactly like a dry leaf in shape, colour and vein markings. There the insect will sit motionless, head drawn up between the fore-wings, the “swallowtails” of the lower pair resting against a twig in perfect resemblance of a leaf-stalk. As long as the butterfly does not move it remains invisible and safe.

Apart from “mimicry” many other remarkably clever designs are utilised to conform with the paramount law of Nature—to eat and avoid being eaten! One that is really interesting in the extreme, is worthy of mention.

In the arid deserts of Africa, the centipede utilises the “prickly pear” as a means of self preservation. Before going to sleep, during the day, it constructs a circular “zareba” of small spiney portions of the plant that are fallen to the earth, the walls about an inch and a half high, enters this enclosure, closes the entrance and retires. One of the centipede's most deadly foes is the black tarantula (Niger Lacosa), and it is against this danger the “‘zareba” is made. The tarantula arrives at the dormitory and immediately seeks to find an entrance. Round and round he works in vain; but he is a “stayer” and will not abandon the enterprise.

A loud buzzing sound draws rapidly nearer and nearer—a big solitary wasp is attracted to the scene—the tables are turned—the hunter becomes the hunted! The wasp, too, instinctively knows a tarantula may be prowling round the centipede's dormitory—the great spider is necessary as an incubator for two of the eggs she has to lay.

If the tarantula has not been too engrossed in dining upon the centipede he hears the wasp's approach and loses no time in vanishing … to be seen is certain death … the winged huntress will readily follow the spider into its lair! On the other hand, should Lacosa not discover the wasp's approach in time to vanish, the shrift is indeed short. The spider is soon stung in a nerve centre, rendered comatose, and carried off to the wasp's burrow. There, two eggs are deposited just below the skin, which in due time hatch into larvae that feed on their host, pupate in the—then—empty shell, and finally emerge, as male and female imago, ready to take the nuptial flight.