The New Zealand Railways Magazine, Volume 6, Issue 3 (August 1, 1931)
The Living Torches of Nature
The Glow-worm of New Zealand (Bolitophila Luminosa), generally known as a “worm,” is, in the “imago” or “perfect” stage, really a “fly” of the order Diptera, family Tipulidae, and closely related to the Sandfly and Daddy Longlegs. This little insect has become enshrined in our fancy on account of the gleaming phosphorescent torch displayed during the last three stages of its existence as larva, pupa and imago.
Mr. G. V. Hudson, F.E.S., in his charming treatise on our “Living Torch,” when describing the larval web, says:
“From the lower side of the central thread numerous small threads hang down, and are always covered with little globules of water …. an unimportant part of the web.”
May not this mean—I mention “en passant”—these “globuled threads” are in reality “lures” that enable the “Glowworm” to prey upon animalcula, as does the larva of the Sandfly (Simulia Australiensis) and other of the outside world's “Living Torches.”
It is my intention to briefly instance a few “Living Torches” of the class Lampydridæ as quite distinct from Elateridæ or “Skip-jack” Beetles.
The “torch” of the Lampyridæ is placed, not at the tail tip, but under the last three rings of the abdomen, nor can it be switched “on” and “off” at will. The “flare” is produced by a slow combustion process of a secretion generated through muscular contraction. This “flare,” if subjected to oxygen, will turn from phosphorescent green to an intensive white glow.
“Lampyridæ Noctiluca” is, in the larval stage, of carnivorous habits; as an “imago,” a “flower-feeder.”
“Drilus Flavescens” has most singular habits. The male “imago,” a quarter of an inch in size, is winged; the female, from three to four inches long, retains a caterpillar form, and goes through life wingless.
The strangest part about the larva is, being parasitic to the common snail. Attaching to the snail's shell by means of a disc sucker, on getting an opening, it works its way in between the mollusc and the shell; finally devouring the “host” completely before the pupal form is entered.
Often there is a long wait before entrance is achieved by the larva. The snail, in no doubt as to the deadly menace outside, hoping against hope, postpones the fatal moment till compelled by hunger or almost suffocated, it throws open its door. The larva, grasping the opportunity, glides in, severs the tendons of the snail's foot, and enters into occupancy. On reaching the pupal state the mouth of the shell is tightly closed with the cast of larval skin, and kept sealed till the emergence of the perfect insect.
The Lampyridæ are found in most regions of the globe, and, as with our own “Glow-worm,” are objects of delight owing to the fantastic beauty effect of their lights, which blaze through the gloom of night, stabbing the darkness with fairy shafts of radiance.
There are members of this widely spread family, indigenous to the tropics, entirely devoid of light production; to them, Nature has given—shall we say, by way of compensation—brilliant colouration. In some groups the females never become “winged,” and remain in a caterpillar form through life. Here the females, by way of attraction towards the winged but torchless males, are endowed with the organs of light giving. Again, there are other groups where both sexes attain to a winged form, and are endowed with the power of light emission in an equal intensity.page 64
The Elateridæ are the Beetle Torchbearers. They are much larger, generally, than Lampyridæ, and bear brighter “lamps,” the light from which is more of “golden” flame than of a pale green phosphorescence.
The name “Elateridæ”—derived from the same Greek root as the word elastic—has been bestowed on this family—more commonly known as “skip-jack”—owing to an ability to spring up into the air; a loud and distinct “click” accompanying the performance. The “spring” is only made should the insect chance to turn over by accident, or become placed on its back. In such a case, the legs being too short to reach the ground, the insect bends the body outwards till supported on the points of the head and tail; then, straightening out sharply, and with a distinct click, the body is projected upwards in a somersault. Should failure to right itself happen the action is repeated till success is achieved.
Pyrophari, an American variety, is named by the Spanish-Americans “Cucayos.” So powerful is the “torch” of this species that a book may be easily read under the luminance. There are many tales in connection with the intensity of its lumination; two of which may be quoted, not only as illustrative, but of interest.
A native saying goes:—
“Carry away that Firefly, but fail not to return it whence thou got it.”
This has emanated from a native custom of attaching these “living torches” to the feet before passing through the dark forest undergrowth. The flares alarm and cause snakes to move out of the traveller's route.
The Creole women utilise “Cucayos” for personal ornaments; such as headdresses, armlets, ear-rings, and the like. The fireflies are attached to elaborate frame designs by means of soft wax. The most exquisite results are obtained by combining Cucayos with humming birds and diamonds.
The insects, which are very plentiful, are caught and kept in tiny cages and fed upon sugarcane. When the fete is over the “Cucayos” are taken home, freed from the frames, given a bath—which completely refreshes them—and recaged for use as a softly glowing “night light.”