IN TOUCH WITH NATURE

Otago Witness, Issue 4029, 2 June 1931, Page 10

IN TOUCH WITH NATURE

A LOVELY JEWEL. By J. Drummond, F.L.S., F.Z.S. Mr G. V. Hudson’s beautiful description in “ The Butterflies and Moths of New Zealand” of the sparkling chrysalis of Danaida plexippus, a widely-distributed butterfly, not very plentiful in New Zealand, has been supplemented by Mr T. Skeates, Titirangi, Auckland, evidently an enthusiastic entomologist. This chrysalis is pale green, garnished with black and gold. “As it hangs pendant from an old fence-board, or from the under-surface of a leaf,” Mr Hudson states, “ it reminds one of a large ear-drop; but, although a jeweller . may successfully imitate the form, he might well despair of producing the clear, pale green and the ivory-black and golden marks that so conspicuously characterise it.” This is Mr Skeates’s description:—“ Lt is so beautiful that many people would not believe it was a living creature. Lt is just a lovely jewel, like polished greenstone, inlaid with pure, bright gold. It hangs from a small white silk ball which the creature, in its caterpillar stage, had made, and which it had cemented itself to 24 hours before it discarded the caterpillar skin.”

A relative of Mr Skeates, next door to him, had more than 100 of these caterpillars on a milkweed shrub, Asclepias, in her garden. She did not like the look of the black and yellow caterpillars with their tigerish aspect and horns at both ends, and she killed them as fast as she found them. While walking in her garden early one morning in February, 1930, Mr Skeates saw an object that looked like a spiral spring hanging to the same shrub. Finding that it was a caterpillar, he took it home, and fed it on leaves of the shrub. A few days later he took nine more caterpillars. He tried them on many kinds of leaves, but found that they would eat only leaves of the shrub on which they were caught.

In a few weeks each caterpillar spun a small silken mat. A silken ball wan made inside the mat. Each caterpillar placed its hind feet on each side of the ball and forced a black substance into the ball. After about six hours the substance had set hard like cement. The caterpillar then dropped and hung head downwards, retaining that uncomfortable position for 24 hours. Suddenly the skin cracked across the middle and dropped to the ground, exposing a bright green chrysalis. In the following few hours the chrysalis changed its shape, and then put on its glorious apparel, as described above.

When the chrysalids had changed into perfect butterflies Mr Skeates kept two females and four males. He liberated two pairs in a garden next door, hoping that they would lay on the shrub that had sheltered them in their caterpillar stage; but towards evening they followed the setting sun over the hills and disappeared. He kept six in a large cage made of mosquito netting, feeding them on dissolved honey sprinkled on cut flowers in jars. After two weeks a pair mated. He saw a female trying to lay on a milkweed he had bought in the city. It was not successful. A few days later it seemed to be near death, and soon died.

Feeling that it was time the mated female first mentioned began to lay, he picked it off a ffower and placed it on the milkweed. It immediately laid a batch of pale yellow eggs on the under side of a leaf. It would not lay on any plant except the one on which the caterpillars had. fed. After 16 days the eggs hatched. ‘“With seed from the original milkweed next door, he grew young plants, on which the newly-born caterpillars lived until they were almost fully grown. They devoured the plants down to bare stumps. A plant of medium size was obtained. Mr Skeates was starting the caterpillars on it when a very cold July spell came along and killed them all, although he” kept them in a warm room, with a lamp near them at night, warming them up to about 56 degrees.

The mated female particularly observed was aged two weeks when it mated, and three weeks when it began to lay. After it had laid about 50 eggs on the milkweed it became sickly and lived for only about a week after laying. Its mate, the male, lived for 14 weeks. The others lived from two weeks to five weeks. The female that tried to lay and died soon afterwards was opened up with a razorblade. In it there were 50 eggs ready to be laid; 50 would have been ready in a week; and 50 more, very small, would have been ready at the end of another week. A female of the species evidently lays about 150 eggs in one season. Each batch of 50 was in a different stage. They were all in strings. “ The eggs,” Mr Skeates writes, “ are the most wonderful pieces of small work I have seen. The are ribbed from top to bottom, and ribbed across. The enclosed sketch, will give you an idea of their beauty of construction. The empty shell is clear like glass. Under the microscope it looks like a pretty cutglass cup. Since I discovered these beautiful creatures I have become completely wrapped up in the butterflies. I am anxious to study the most beautiful species, like those of South America.”

Mr Skeates refers to his insects as Danaida archippus. There is'some confusion here, as in the nomenclature of many insects. Danaida archippus, apparently is identical with Danaidia plexippus, and in this article Mr Skeates’s observations are published, as applying to plexippus. The caterpillar and chrysalis stages have been clearly described by Mr Skeates. Mr Hudson’s description of the perfect insect shows that it has a wing expansion of from three inches and three-quarters to four inches and a-quarter. All its wings above are rich orange-brown, bordered with black. There are two rows of small white spots round the margins of all the wings, and several orange-brown spots near the point of each fore-wing. There

are similar markings on the underside, but the under-surface of the hind wings is very pale yellowish-brown.

The size, beauty of form, and brilliant colours that characterise many of the butterflies of tropical America have been the wonder of the world for more than 100 years. The Didius butterfly, with a wing expansion of six inches, is a beautiful pale moonlight blue. The Menelaus of Brazil is another blue butterfly. The Venus is brilliant glossy blue on the upper surface, with white bands and spots; on the under side of its wings it has a colour scheme of chocolate and white spdts, blotches, and rings. Sulskowsky’a butterfly, smaller than the others, its wing expansion being only about four inches, is niother-o’-pearl, but the tips of its forewings are brown. It has a tail to each hind wing, and above each tail there is a red dot. On the under side its wings are marbled with pale brown and brownish-white. All this enraptures people’s sense of beauty; but, after all, beauty is only skin deep. A butterfly’s life history, not its appearance, is the marvel, and Mr Skeates can trace the processes from egg to caterpillar, chrysalis and perfect insect, as well in the homely Danaida at Titirangi, as in the gorgeous butterflies of South America.

Messrs Benn Brothers’ popular journal of science, Discovery. London. has celebrated its twelfth birthday. Manypeople in the English-speaking ’world will wish it many happy returns of the day. Its editor. Mr John A. Benn, and its distinguished trustees, Sir J. J. Thomson, Sir F. G. Kenyon, Professor A. C. Seward, and Professor R. S. Conway, have provided the public with a very acceptable record of the advance in knowledge and the march of science. They have described scientific discoveries of the highest importance, and have discussed fresh aspects of history, archaeology, literature, and other subjects. In this mission they have obtained the help of innumerable experts, each speaking with authority on his own subject. In the birthday issue, Sir J. Arthur Thomson, of Aberdeen University, an eminent writer on popular natural history, reviews the past 12 years’ progress -in views the past 12 years’ progress in biology, emphasising the increased recognition of amelioration of human life. This is a thoughtful article, full of information that the public, perhaps, cannot get, except in Discovery's pages.