IN TOUCH WITH NATURE

Otago Daily Times, Issue 19531, 14 July 1925, Page 2

IN TOUCH WITH NATURE

BENEFICENT BEETLES. By J. Dbttmmond, F.L.S., F.Z.3. A very tiny, but very handsome beetle, which ran over the paper on which an Onehunga lady was writing a question as to a plant in her garden, is a beneficent Australian. This member of the great coleoptera, the hard wings, belongs to a family famed in the Old Country’s legends and folk-songs, known to entomologists as the Coccinellidffi, and to ordinary people as the lady-tods, a pretty title, the origin of which is not obvious. Lady-birds are not merely harmless insects; unlike some of the pernicious woodborers and other beetles, they do much good by attacking the aphis and all sorts and conditions of scale-insects. This particular benefactor is the steel-blue ladybird, Orcus ohalybeus. It is so small, about an eighth of an inch long, and almost as broad, that a lens is required to disclose its beauty. It is uniform deep metallic steel-blue. It came across tire Tasman Sea to check scale-insects in citrus orchards in the Auckland Province. Some beetles are vegetarians in the grub stage of their lives. All ladybirds have the advantage of being carnivorous in that stage and in the adult stage, in which they are most conspicuous. This little Australian favours warm climates, and cannot stand the winters of New Zealand’s “sunny south.” In this respect, its tastes coincide with those of another Australian member of the ladybird family, a long-named one—Cryptotemus montrouzieri—which gives particular attention to the moaly-bug. Its body is uniform black, but its head, its thorax, and the tips of its wing-cases are picked out with light yellow. Still another Australian in New Zealand, Leis conformis, a bright yellow lady-bird, checks the aphis on cabbages and melons. The commonest lady-bird in New Zealand is a European, CoccineHa punctata, introduced from England. Its usefulness is beyond question, out limitations are imposed on it by a parasite.-

Invitations to lady-birds in other Gauntries are necessary because New Zealand’s own lady-birds are small and_ not very abundant. On© of them, in size, shape, and spots, is somewhat like the elevenspotted lady-bird of Europe, just referred to. Fifty years ago, New Zealand children held lady-birds, apparently natives, on their open hands, and watched them fly off in baste in response to the warning :

Lady-bird, lady-bird, fly away home. Your house is on Are, your children are gone.

The rhyme, and the warning it expresses, are believed to have arisen in the hopfields of Kent, where fixes were lighted after the picking to burn hop plants, in which lady-birds had their homes. Economic entomologists have not given much attention to lady-birds in New Zealand because they do not occupy a prominent place in the dominion’s insert fauna. Tin world has more than 2000 species of them. Of the total, Australia has more than. 100, New Zealand a comparatively few. Efforts to establish a useful Californian lady-bird in New Zealand have been unsuccessful. The most successful Australian lady-birds in New Zealand are the blue one, Rhizobius ventralis, invited originally to help lemon and orange growers in the Auckland Province, and later turned on to scale-insects on blue gums in the South Island, and Novius cardinalis. credited with absolutely controlling the cottony cushion-scale.-Dr R. J. Tillyard estimates that 30 per cent, of the economic damage dom by insects to the food supply of New Zealand may be placed at the door of native species. The chief offenders are the grass-grubs, the subterranean grossgrubs, and their allies. Many ox the worst insect pests introduced are mealybugs and aoaJe-insects. He regards the Australian paper-nest wasp. Polistes, which is spreading all over North Auckland, as a valuable ally of the orchardist, as it attacks the pear-alug and the caterpillars of moths and butterflies, masticating them and using them as prepared food for ifa grubs. The Hymenoptora, to which the bees, the wasps and 'their allies belong, is a great order, but it is very poorly represented by natives in New Zealand. Most of the members of that order are highly beneficial, and Dr Tillyard sees in New Zealand’s poverty in respect to them a difficult problem in entomology. He suggests that economic entomologists in New Zealand should sot themselves the task of wisely filling the gap in the Hymenoptora with the greatest beneficial effect on the dominion’s food supplies. Miss Rosalind Moss has a good deal to say about Now Zealand and the Maoris in “The Life after Death in Oceania.” She traces the connection between burial customs and beliefs in a future life in Indonesia, Melanesia, and Polynesia, threading her way through a maze of ceremonies that surround the disposal of the dead. She finds in the Maoris’ description of their Reinga a oloso resemblance to the underworld of South Melanesia, as it is beneath the earth, is, on the whole, a gloomy place, but not a place of punishment, is reached from a leap-ing-off place, and has a guardian or an ordeal. She can find no trace in Polynesia of widows being slain with their husbands. All over Melanesia it was the custom to bury a widow with her husband or strangle her at the grave; and in traces in New Zealand of Hie practice of killing widows with their husbands she sees -some evidence of the Melanesian element in Maori culture, although human sacrifices amongst the Maoris followed Polynesian ideas. Belief in a long and well-defined journey to the afterworld is ascribed by Miss Moss to the actual migrations of ancestors of people who hold the belief. The canoecoffin originally was a vestige of migrations but in some places it has been transformed into a soul-boat, to carry the soul to the land of the dead. Miss Moss has used extensively stores of knowledge accumulated by Messrs Elsdon Best, J. Cowan, E. Tregear, A. Shand, H. D. Skinner and earlier New Zealand scholars. Her book is indispensable to a complete study of the Maoris and other peoples of the Pacific. A copy has been sent by Mr Humphrey Milford, publisher, to Oxford University, with the compliments of tlie delegates of the Clarendon press. “Some strange forms of life, known to biologists as Myxogastres, occur near Christchurch,” Mr J. B. Armstrong writes. “They were at one time generally believed to belong rather to the animal kingdom than to the vegetable kingdom, but their mature state so clearly approaches to the structure of puff-balls that little doubt is left as to their being plants. They differ from the majority of fungi in their spores, on germination, producing bodies capable of spontaneous movements which combine together to form a plasmodium. This varies in appeamce on different lost plants. The commonest species in New Zealand occurs on grasses, especially introduced grasses, and the so-called Spumaria alba. When the fungus is mature and ready to release its spores, it looks like one of the spider tents common on low bushes. The mass usually takes in several blades of grass for support. It is pulpy at first, but later it dries up and contains a dusty mass of spores and broken threads.” One of the Myxogastres, Mr Armstrong adds, causes a disease known as finger-and-toe on cabbages, turnips and other vegetables. A few years ago it was epidemic, and was very destructive in many gardens in and near Christchurch. The root of a victimised plant is the part most liable to attack. The spores enter by root-hairs and fill the plant’s cells with plasmodium, producing large swellings and causing complete rottenness, which results in failure of the crop. He believes that the disease is always most prevalent where much Chemical manure has been used, acids in the manure, apparently, supplying food for the fungus. Ho describes another Myxogastres, a common one, found amongst sawdust,

rotten wood and dead leaves. It is yellow or white. It sometimes spreads over the soil in neglected flower-pots and destroys the plants in them. Officially it is Euligo varius. -Another species of those fungi, known as “corky scab” or “dry scab,” sometimes very destructive, has been found amongst potatoes after lifting. Mr Armstrong concludes : “In addition to the species 1 have mentioned there are in our forests some beautiful little fungi which authors refer to the Myxogastres, but which seem to me to be better placed in a different division of the fungi. All of these have their spores enclosed in beautifully reticulated network, or oapalitium.”