The Ways of the Earthworm

Dominion, Volume 26, Issue 302, 16 September 1933, Page 20

The Ways of the Earthworm

(By

J. Drummond, F.L.S., F.Z.S.,

~ tor “The Dominion.”)

THERE is no reason for Mr. J. M. P. Tapp, of Onehunga, to feel grieved when people poke fun at him because he is interested in earthworms. “Frankly,” •he writes, “I am sometimes called a fool, but I take it with a grain of salt.” In this case the proverbial grain of salt is not requisite. He need only claim companionship with Charles Darwin, the greatest naturalist, whose wonderful brain and patience produced a large volume on earthworms and their influence on soil and vegetation; that, is, on the value of land to the agriculturist and the pastoralist. If Mr. Tapp is a fool for being interested in earthworms, Darwin was an idiot. Since Darwin’s time further volumes have been written on earthworms, notably by Professor F. E. Beddard, of London. Several of these are masterpieces, but Darwin’s work remains pre-eminent for close observation and sane reasoning. Professor Beddard found that earthworms relish raw meat, prefer green cabbage to red, celery to both, and value onions above all othei vegetables. Their liking for onions is the cause of Mi. Tapp s complaint against them. In the middle, of last mouth he transplanted 1200 onion plants. After rain he was annoyed to discover that 160 had been pulled up. Most of<these had been dragged to earthworms’ holes In the ground. He watched earthworms on a Devonport lawn, planted recently. In parts where there were earthworms’ holes the young grass began to disappear like magic. At first he blamed snails and slugs for the whole thing. Investigating at night with a torch, he saw earthworms helping the molluscs. This surprised him greatly, and lie became more interested in earthworms than over before. He now flashes his torch on them in the vegetable and flower garden at Onehunga. He saw them reach out from their holes as far as nine inches, twist themselves around plant's, pull them out by gently tugging, and slowly drag them to their holes. He was surprised at the sizes of some of the plants and the numbers that disappeared. The earthworms seemed to do most damage during damp or rainy weather. At Devonport and Onehunga he saw big earthworms. Held by their tails, they stretched up to eighteen inches. In the King Country he saw earthworms that stretched as much as two feet six Inches. These seemed less active than the common garden earthworms. Darwin beut his powerful brain to show how earthworms form vegetable mould. To prove how they enrich the soil by burying leaves and by constantly turning iti over and exposing fresh surfaces to the air and the rain, be estimated that on one acre as much as ten tons of earth,

or a layer a fifth of an inch thick, may be brought up every year and spread by the wind and ot-her agencies. The accumulated effect, during periods and eras cannot be estimated. Professor Beddard went further In a neat sentence he wrote: “On the sides of a hill, material brought from below by earthworms would tend to roll down the slopes when dry, and would increase the debris carried to the sea by streams and rivers; and continents formerly deposited under the sea may owe no small proportion of their size to the continued work of earthworms in past ages.” Other friends of the earthworms claim that they help historians so largely by their work that many ancient buildings and monument's have been sunk in the earth and preserved. They do all this without eyes, although sufficiently sensitive to light to distinguish day from night, and without the sense of hearing. Like observers elsewhere, Mr. Tapp noted that earthworms are hypersensitive to vibrations tn the ground. His best results were obtained when he approached very carefully and flashed bis torch. Some that he touched responded quick and lively, darting back into their holes like pieces of elastic stretched and let go. The rapidity with which earthworms dive into their boles when the ground is shaken by a blow or a heavy footstep has astonished many people. Earthworms kept by Darwin took no notice whatever of shrill notes from a metal whistle repeatedly sounded close to them, or of the deepest and loudest notes of a bassoon. When pots in which they lived were placed on a piano they were very sensitive to vibrations caused by notes sounded on the piano. The explanation is that earthworms cannot bear, but they perceive vibrations that pass through a solid body. New Zealand has about fifteen genera of earthworms, divided into about, fifty species, including seven species of Maorldrilus, in which some of the big earthworms are placed. In addition, about twelve species of intro duced earthworms have been recorded. One family is represented in New Zealand and India, but not in intermediate countries. A small family is widely distributed in temperate countries, occurring in New Zealand. South Australia, West Asia, North America and South Africa. Earthworms inhabit every part of the earth except the Far North and the Far South. There seem to be more in the temperate regions than in the tropics. The most widely distributed genus, Notiodrilus, includes five New Zealand species, also species in Patagonia, the islands of the Southern Ocean, South Africa. America, and Australia. A family plentiful in New Zealand, Patagonia. South Africa, and Kerguelen Land, and present In New Caledonia, India ami the West Indian Islands, is almost, absent from Australia and Tasmania.