IN TOUCH WITH NATURE

Otago Daily Times, Issue 21990, 27 June 1933, Page 2

IN TOUCH WITH NATURE

THE LAMPREYS THEY SPAWN IN THE RIVERS. By J. Drummond, F.L.S., F.Z.S. A Waiiganui correspondent has challenged a statement by Mr B. T. Booker that lampreys go up rivers to spawn. " I happened to discuss ths question with a local Maori last winter," this correspondent writes. "He stated emphatically that lampreys do not go up the river to spawn, but that they go up the rivers early in winter and return in February on their way to the sea, spawning there. Maoris catch them in large numbers and they are full of spawn. 1 should like to have a full account of lampreys' movements, as Webster's dictionary states that ' these Ash go up the rivers to spawn.' "

All authorities support Mr Booker. The best authority, Dr Starr Jordan, states that the eggs are laid in brooks away from the sea. Another American expert Professor Surface, reported on lampreys in inland waters: " When physical changes take place, lampreys. turn their heads against the current and set out on their long journeys to sites favourable for spawning. These may be from two to eight miles from a lake. They are likely to crowd up all streams flowing into the lakes, inspecting the beds of the streams aB they go. They do not stop until they reach favourable spawning sites. If there are insurmountable obstacles in the way, such as vertical falls or dams, they turn around and go down stream until they find another stream, and they go up it. About a mile from the mouth of one stream there is a vertical fall more than 30 feet high. Lampreys cannot surmount this. They have never been seen trying to do so. After clinging with their mouths to stones at the foot of the falls for a few days, they work their way down stream, carefully inspecting all the bottom for spawning sites.

Dr C. Claue, of Vienna, simply notes that lampreys ascend rivers in the spring to spawn. " The Standard Natural History," published recently by Messrs Frederick Warne and Co., has the following account of lampreys breeding habits:—-"During the winter those that spend part of their time in the sea migrate to the rivers. They make their way up by fixing themselves with their suctorial mouths to fishes, or to the bottoms of boats, or by swimming with easy, eel-like movements. On arrival at a suitable place they pair off. Each pair makes a groove on the bottom of the river. They surround this with a palisade of stones, transported one at a time by the use of the mouth-suckers. The eggs are partly covered with sand or mud. Spawning saps their vitality, and at the end of the breeding season they are exhausted. They drift down stream in a moribund condition. It is doubtful if many survive to reach the sea again."

The latest English work on fishes, a comprehensive history by Mr J. R. Norman, published by Ernest Benn, has the following details: —"Young lampreys, called prides or niners, are hatched some 10 or 15 days after fertilisation of the eggs. They remain in the nest for about SO days. They then wander down stream. Having selected a suitable place,, they burrow in the sand or in the mud. They live in tubes for three or four years, quite blind and toothless, feeding on minute organisms or on organic matter in the mucf. Minute particles of food are carried through the mouth into the pharynx by currents of water produced by special hairy cells working in unison. The particles become entangled in strings of mucus and bands of tiny filaments , sweep them into the stomach. At the end of from three to five years a metamorphosis occurs, and the young lampreys suddenly assume the characters of adults. Eyes appear first.. The mouth _is contracted and takes on the suctorial disclike form characteristic of lampreys, the tongue and horny teeth are developed. At the same time, important changes take place in the form of the skeleton, gillpouches, alimentary canal, and kidneys, the whole process taking about_ .two months." The remarkable mouth is developed last. When it is complete, the lamprey has an equipment " with which it attaches itself to its victims, takes its food, carries stones, builds up and tears down its nest, and holds its position in a strong current."

There seems to be.no doubt that lampreys at least die after spawning. Henry Thoreau, author of "Walden Pond," many years ago made a note of this. Later observers bear him out. He wrote: "It is thought by fishermen that they never return to their spawning places in streams, but waste away and die, clinging to rocks and to the stumps of trees for an ihidefinite period, a tragic feature in the scenery of river bottoms worthy to bo remembered with Shakespeare's description of the sea-floor."

Taiko is the name Maoris use for an all-black petrel that lives mostly • in the northern parts of New Zealand. A letter from Mr C. Seymour, 135 Edgeware road, Christchurch, seems to show that on the Chatham Islands the name is used for another species of petrel, with a white breast, smaller than the common mutton bird, but, according to Mr Seymour, better eatingl Firty-three years ago he went out with a party of Monoris, including Mr Horomona Rehe, father of the late Mr Tame Horomona Rehe, t>> Tuku, on the south-west of the Chathams. Going .inland for about Ahree miles, on April 2 they came to a place called Moeahi, where they camped. In peaty ridges there they found taikos. They had to work very hard from daylight to dark to get 10 birds in a day. Mr Seymour had had some experience with taikos previously, having found a few isolated ones in limestone gullies on the Chathams. In the peaty soil he saw a ponga tree-fern 12 or 15 feet high, which had grown from a small ponga used to plug up the entrance to a tiko's burrow.

The 6trange vegetable caterpillar, inject at one stage of life, fungus at a later stage, is found in several other countries, as well as in New Zealand. Dr W, H. Weston, jun., Harvard University, haa reported it from Barro Colorado Island, in Gatun Lake, Panama Canal. In an article in the latest number of The Scientific Monthly, New York, on the fungi of that island, he does not give much information about the vegetable caterpillar, which he refers to by its scientific name Cordiceps, but he has a photograph showing the stem of a fungus arising from the dead body of a beetle which the fungus destroyed, and he describes this vegetable caterpillar as slender and beautiful.

Clearly and graphically he records other fungi on the island. In genera] terms he writes: "Their remarkable diversity of form, structure and method of growth, their rapid and surprisingly efficient methods of development, their relation to plants, to animals, even to man, commend them to attention. Without their activities, this great cycle of jungle growth could not go on, as the whole vast machinery of plant life and of animal life dependent upon it is prevented from being clogged with accumulated materials by the activities of fungi, which break down complex, elaborate substances into raw materials again." This journal published by the Science Press, ranks amongst the best popular scientific literature in the world. The articles are easily read, but are profound, in most caßes practical, always full of information. The present number deals with better live stock, earthquakes, cancer and other subjects. A small white-winged moth, sent by Mr J. W. Shannon. Tvemnera. Auckland, is not the small cabbage white butterfly which has sprung info notoriety in New Zealand. The cabbage-white is easily recognised by its dull white wings, each wing bearing a black dot. From tip to tip, its out-stretched wings have a spread of about two inches. Mr Shannon's specimen, which he feared might be the cabbage-white, is less than half the size of the cabbage-white, and is a native of New Zealand, belonging to a group of delicate moths, characterised by a lack of gay colours but by great beauty.

Patricia Lees, Kitchener road, Milford, is watching the development of a big caterpillar found burrowing into sandy soil on a public road. If it is still alive and is allowed to bury itself, it will slowly be transformed into a fat mahogany-coloured chrysalis, about two inches long, with a peculiar process springing from its head and bent down

under the head. It will remain an inert chrysalis through the winter; but in November or December, quickened by summer warmth, it will be transformed into a large and handsome perfect insect, a hawk-moth, Sphinx con.volvuli, a species with such a wide range that it is almost cosmopolitan.