NATURE NOTES.

New Zealand Herald, Volume LXIII, Issue 19406, 14 August 1926, Page 1 (Supplement)

NATURE NOTES.

BATS AMD THEIR WAYS.

BY J. DRVMMOND, F.L.S.. F.Z.S

A bat, caught near a forest on the Coromandel Peninsula, is a member of Nfew Zealand's long-tailed species. The species is not plentiful, but is more plentiful than this Dominion's only other species of bat, which has long ears and a short tail. The long-tailed species has a far-flung connection with other bats; the short-tailed species is isolated, and belongs to New Zealand alone, but has been reported from both islands. It usually has been found singly, but one large colony was discovered many years ago on the Little Barrier Island. It probably is there still. , ■

New Zealand's short-tailed bat is particularly interesting to zoologists, as it occupies a unique position among the enormous number of species of bats known. Hardly any observations have been made of its habits. Some of these may be guessed, as they are suggested by its physical peculiarities. Its adaptations seem to show that, in addition to hunting for insects in the air, like ordinary bats, it also searches for them on the branches and leaves of trees. It is able to do this with ease by using sharp claws, peculiarly shaped. An additional joint in the middle finger enables it to fold its wings in a very small space. The conclusion that the short-tailed bat's special adaptations give it facilities for crawling on branches and trunks is justified by the general observation that creatures which live in forests often have special structures suited for getting along among branches. The feet of monkeys, squirrels, sloths arid tree frogs illustrate this. Many typical forest animals, as flying foxes and flying squirrels, sail or glide in the air. Some caterpillars that feed on the leaves of forest trees spin threads and descend on them to the ground to enter their chrysalis stage.

One of the strangest bats, so far as j habits aire concerned, is a largo bat of the Caribbean region, which eats fishes, flying close to the surface of the sea like a petrel and coursing backward and forward looking for its prey Some bats catch small birds, or suck the blood of large animals. Some, notably flying-foxes, are fruit-eaters. As most bats feed on insects, alj have the same style of flight. They neither soar nor glide like some birds, but all are remarkably quick in turning, ' twisting and doubling. Glowworms give themselves away at night to bats, whose uncanny appearance sometimes is increased by fiery teeth, the result of raids on luminous insects. Bats are almost the only mammals that, can fly, if men with their artificial inventions of these days are excluded., About twothirds of the known creatures of the world can fly or glide through the air There are about 600 species of bats, all good fliers, 60 species of flying fish, 20,000 species of flying birds —New Zealand's quaint kiwi and lovable weka are among those that' cannot fly—and more than 400,000 species of flying insects. Compared with the size and weight of the body, insects have much larger wings than bats or birds. For each pound of body weight in a mosquito there is a wing area of more than four square yards. For each pound of body weight in an average butterfly there is a wing areal of moxe than three square yards.

" Ever since I was a boy," the Rev. W. J. Elliott writes from Cambridge, " I have watched the peculiar habits of the-borer. I .am still a-little puzzled, over its strange appearance and subtle ways of working. As a New Zealander I am very familiar with our .fine variety of useful trees'; and as there is nothing like practical experience for either confirmation or disillusionment, one is able from this viewpoint to confirm a good deal of what Mr. D. Miller, Government Entomologist, stated in your column recently. He suggests a sort of sixfold defence against the attacks of the borer, but the various shields are by no means impregnable. Even the store timber in stacks is frequently attacked now. During a recent visit to the King Country I made some observations. I found that two or three different kinds of borer are very busy there. A friend told me that he saw a lot of . timber in a stack where it had only been some six weeks sawn. It was simply riddled. This was somewhat mysterious. My friend was curious, so he carefully examined fired tree trunks standing nearby. There he found the enemy. Some.of, them had wings. He caught two or three of the winged ones and placed them in a box with a hard piece of sawn timber. .They very soon bored several hples in it. I am sure that these Winged ones are very prolific. If their rapid multiplication is to be restrained some more drastic remedies must be discovered."

A lady in Hamilton, writing on the scents of flowers, asks if any native plants of New Zealand as well as the tea-tree or manuka have a strong aromatic scent. Perhaps some other correspondents can supply the information. The'aromatic scent of the tea-tree, and of its larger cOusiri, the manuka, is unmistakable. It belongs to a group of flower scents that includes the scents of aniseed, vanilla, cloves and cinnamon. The scent of the tea-tree Is never so strong as to be unpleasant. Some of the most highly developed flower scents, and some of the sweetest, become unpleasantly heady. The scent from a gorse hedge may be decidedly so. A complaint has been made that the syringa, plentiful in New Zealand gardens, is "too sweet, troubling and molesting tho head in a strange manner." A lady writer found that the scent of a bunch of jasmine, another garden favourite, on a very hot night. gave rise to the suspicion of a dead rat under the floor. The common convolvulus of the Northern Hemisphere, an unwelcome and obstinate guest in many a New Zealand field and garden, has a scent in which bitter almond predominates. New Zealand's own convolvulus, which is closely related to it, may have a similar scent.

Sir. H. W. A, Wilkinson, Wanganui, has asked if there are any light-producers, or luminous creatures, in New Zealand, except the glow-worms seen in caves, forests, and road-cuttings. These are the most conspicuous producers of artificial light in this Dominion, not counting gas companies and hydro-electric schemes,' but, doubtless, there are many others. Mew Zealand's glow-worms, as explained in this column previously, are flies, that is. members of the diptera. In .other countries, glow-worms are members of tne order of the beetle. Luminescence is found in jellyfish, sea-pens, brittle-stars, molluscs, squids and fishes, but, it is stated, not in any creatures that live in fresh water. Most luminescent organs flash only when stimulated, and the light organs often are controlled by nerves.

Some creatures are luminous during the breeding season only. The light usually is of low intensity; the light of the American firefly has a strength of from 0.02 to 0.0025 candle-power. While luminescence seems to serve definite purposes in some cases, no generalisation can be made as to its usefulness. It may he a .signal between the sexes; may be a lantern; may be to lure prey to the owners of light-producing organs; or may keep schools of members of marine creatures together. There is no obvious reason why the grubs, and even the eggs, of some insects should be luminous. Some luminescent creatures are blind; a deep-sea. crustacean has luminescent organs inside its i bronchial chamber.