IN TOUCH WITH NATURE

Otago Daily Times, Issue 21984, 20 June 1933, Page 2

IN TOUCH WITH NATURE

COLOUR SCHEMES HOW THE BUTTERFLIES USE THEM. By J. Drummond, F.L.S.. F.Z.S. Mr G. V. Hudson, in his large and beautifully illustrated volume on New Zealand’s moths and butterflies, has a clever chapter on the remarkable colours of these insects. Their wing patterns, he explains, are so varied that they resemble almost every possible environment, including bark, moss, dead leaves, lichens, twigs, seeds, and petals of flowers. He finds it almost impossible to draw the line between merely ornamental colours and colours that are useful for protective purposes, enabling the insects to hide from enemies. The. males often, by no means always, are more brilliant than the females. The most important explanation of bright colours in insects and in all other creatures is Charles Darwin’s theory of sexual selection. This sets out that in most species there are more males than females. On account of the greater numbers of males, the females, when mating, have a choice. They may mate with males they prefer, jilting males they do not prefer or dislike. They exercise sexual selection. The females ,-ye influenced in their choice by the males’ bright colours, and by frills, tqfts, and other ornaments, but mostly by the colours. The colours and the ornaments are charming in the females’ eyes. They excite them, to the disadvantage of the plainer males. The theory of sexual selection took the world by storm when Darwin first put it forth. In these days of worldwide investigation it is somewhat discredited or brushed aside. A long, careful, and extensive study of New Zealand’s moths and butterflies has left Mr Hudson convinced that sexual selection has exercised a profound influence on the evolution of species. He knows of no theory except sexual selection that explains adequately the extraordinary colours, marks, and structures in many male insects. Opponents of sexual selection argue that an impossible measure of intelligent discrimination is attributed to females when they are credited with ability to choose the most brilliant males. The critics ignore the fact that insects know much more than human beings give them credit for. In any case, Mr Hudson points out that even man seldom exercises his high intelligence when he mates with the opposite sex. Human beings are no better than the insects when mating is concerned.

. A new theory is offered by Major R. W. G. Kingston in, a book of 400 pages entitled “ The Meaning of Animal Colour and Adornment.” He is a naturalist with unusual powers of observation. His work is original. His first contribution to science was “ A Naturalist in the Guiana Forest,” charmingly written, and delicately illustrated. He followed this with an absorbingly interesting study of instinct and intelligence. His latest book is profounder than the others. His theory is that males’ colours are rather an expression of fear and anger, associated with members of their own sex, and used in their conflicts for females. Fear and anger, he argues, are the dominating emotions in all creatures, from mammals to insects. They are expressed externally by two opposing colour patterns. One of these helps them'to conceal themselves from enemies. The other is threatening. If fear predominates, the concealing pattern predominates in the colour scheme, and the creature blends more closely with its environments. In anger, colours and ornaments become conspicuous.

Elsewhere, Major Kingston has noted the same butterflies’ _ characters as Mr Hudson has noted in New Zealand’s butterflies. He has seen many butterflies that resemble dead leaves, not only_ in colour and markings, but also in mimicking midribs and cross-veins. He has seen moths with wing colours that harmonise perfectly with rocks, stones, leaves, sticks, lichens,’ and bark. Butterflies are the most gaily-coloured creatures in the world. According to Major Kingston, male butterflies fight with their 4 colours only. As colours are their weapons, they. require colours in a high degree. They are supreme in the splendour and profusion of their war paint. Male moths and female moths do not differ greatly in colours. The explanation offered is that male moths compete mainly by smell, and that in their case difference in colours from females is unnecessary. Major Kingston's theory has not been subjected to the test of "investigation and criticism. It will be adjudicated upon later. In the meantime, Darwin’s theory stands as the simpler one and the most probable.

This book throws light on antics and gesticulations in courtship, _ and on the significance of song. A bird’s song is regarded as an act of rivalry. One bird tries to emulate another, to shout it down. Chaffinches sing against each other, their efforts ending in combat. Song-thrushes answer one another. Major Hingston describes song as a gesture between male and male. If it is a gesture between male arid male, he asks what is behind the gesture except threat and hostility? It may be said that males compete with each other in order that a listening female can choose the most melodious. . This is dismissed as impossible, because the songsters almost always are far apart; one male is close to the female in the male s own territory; the other male is remote. If both competed for the female’s favours, both would go close, or would sit at equal distances from her. The rivalry agrees with the view that its utterance is a threat. Song i_s the males’ long-range artillery in action. A copy of Major Kingston’s book, full of information about insect, birds, and mammals, has been sent by the publishers, Messrs Edward Arnold and Co., London. Price, 18s net.

A few years ago Mr H. Cundall, of Broadway avenue. Timaru, reading about the sufferings of birds in the winter, fastened two kerosene tins on a post m a quiet corner of hie garden. After breakfast every morning He put out a few handfuls of crumbs. It was not long before there was a number of visitors, including 24 white-eyes or wax-eyes. Year after year they came, probably the same individuals. . This year’there are only 20, darting and twittering, and very pretty in bright olive, dark grey, yellow, white, and chestnut. First comes a magpie at dawn, then a blackbird and a songthrush. The white-eyes are afraid of all other birds except sparrows, which they chase away. As many as 10 white-eyes get on to the tin at one time. Mr Cundall reports that they are so gentle and sprightly that even a bed-ridden person would be interested and amused bv them if the bed were near the window and if somebody rubbed a piece of stale ■bread ou a grater and offexed the ciumbs to the visitors. One night a few weeks ft „ o Mr Cundall heard a noisy twittering. He thought that his little friends had returned. Although tlic night was too dark to sec, the volume of sound seemed to show that there were hundreds. Only 24 attended for breakfast, but Mr Cundall was pleased to find that his visitors had not deserted his place.

In " The Life Histories of New Zealand Birds ” Mr E. F. Stead describes the white-eyes’ usual note ns a sharp, highpitched whistle, a single syllable repeated at intervals, but much more quickly when the white-eyes are about to fly and when they are in flight. The males' songs m spring and summer ring on his ears with charm —“ a soft, melodious warble of four or five notes, repeated frequently, always ending with three or more of the ordinary shrill notes.” Mr Stead heard them sing in this way when they perched with their mates by their sides, also when alone, sitting absolutely still, usually in the sun and facing it, often preening their feathers in the pauses of the songs.

Early in November Sir Walter Buller stopped to observe white-eyes amongst the small, white, bell-shaped, fragrant flowers of the kohia creeper, the native passionflower. Being full of nectar, the flowers attracted little golden butterflies and swarms of other insects. White-eyes sipped the nectar and caught the insects, finding there meat and drink. They littered sharp, plaintive notes, repeated at short intervals. On the wing they had a rapid, twittering note. During the nesting season Sir Walter r Buller heard males producing a low, musical strain, exquisitely sweet, but subdued, as if the songster was singing to itself or to please only its mate.