IN TOUCH WITH NATURE.

Otago Daily Times, Issue 20704, 30 April 1929, Page 2

IN TOUCH WITH NATURE.

THE FROG-HOPPERS. By J. Drummond, F.L.S., F.Z.S. Correspondents occasionally send the twig of a shrub, frequently a native oleana. with a small quantity of pure white frothy substance where a leaf springs from the stem. Inside the froth, always there is a small grub. The froth is produced by the grub, which lives in it while it sucks the plant’s juices. The grub is inconspicuous, but, in the course of its marvellous metamorphosis, it develops into a small insect, about a quarter of an inch long, embellished with green and reddish marks. It is related to the cicadas, commonly called locusts, which, 111 . day’s, when the sun shines, stndulate so loudly that they make trees and shrubs resound with their music. Its family is the frog-hoppers, a title earned by the_ resemblance of at least some of them, in their. perfect stage, to frogs, ihey are known also as spittle-insects, on account of the froth, which is called cuckoo-spit, because, in the Old Country, before insects were studied seriously, there was a belief that it was the saliva of the cuckoo; Otherwise, these insects are the Cercopidte, representing their ancient Greek name. The commonest New Zealand member, just described, is Phitemua trimaculatus. There is nothing repulsive in the froth. The insect suffers an injustice by one of its popular names. - The froth is not saliva, but simply supplies of the sweet juice sucked from plants, The grub, equipped with piercing and sucking organs, presses them to the' stem of the plant. As described by an English naturalist, it gets such a rich supply of sugary sap that it overflows with sweetness. Working its body up and down it converts the overflow into a soapy mass. Utilitarian reasoning has led to the theory that the grub’s object is to keep itself moist and to protect itself from enemies, which may not know that there is a little creature inside. The protection does not seem, on the surface, to be very effective, but it is stated that few enemies will touch the froth. Professor J. A. Thomson sees in the device a means of saving life by blowing bubbles. He explains that along the under side of the grub’s body there is a runnel, which holds air. The grub works its body up and down until _ the captured air is mixed with the surplus sweet juice. It is then passed out of the foodcanal. It is whipped sap, made in the same way as a, cook makes whipped egg by _ beating air with a spoon into the white of egg. In the insect’s process, there is added a little wax from glands on the skin and a little ferment from the foodcanal. The sugary sap, the air, the wax, and the ferment are beaten up together. If it consisted of bubbles only, it would soon disappear, but Professor Thomson states that, as it is something like soap, it lasts. The life history of New Zealand’s froghopper has not been written. If it is on the lines of a relative in England—probably it is—the female, in the autumn, lays her eggs in the crevices of bark, and dies soon afterwards. The eggs hatch in the spring. Each young frog-hopper has its head bent down upon its breast. Its sharp, piercing beak is adapted to penetrating the skin of young leaves, and its legs grip the plant firmly. If it is placed on a clean leaf and is watched through a good lens, it will be seen to probe with its beak, using sharp needles in a tubelike case. Through its beak it sucks up the sugary sap. This palatable and nutritious food is very abundant. The frog-, hopper thrives. It grows and moults, and grows and moults again. Then it enters the inertia of the chrysalis stage. It grows its wings, its organs and structure change.’ Leaving the froth, it makes its final moult, and -is fully grown, fully winged, a perfect insect, a frothblower no longer. A frog-hopper grub, detached from its froth, was watched under a microscope. It kept its beak down against its breast, thrust the beak into tender shoots, and began _to suck the juices. In a little while it discharged a clear fluid from the ;end of its body. This flowed over, and the grub seemed to 'be in danger of flooding. There was no sign then of froth or bubbles, but the clear liquid was slightly sticky, and looked something like soapy water. About half an hour after the grub had been disturbed, it was seen moving its tail up and down and from side to side. _ With each downward stroke it carried into the fluid a minute quantity of air, which formed a tiny bubble. The process was repeated until the whole of the fluid was converted into froth. By the same movements, the' froth was distributed _all over the insect and around it, and it was again completely hidden from view. In other countries, , there are froghoppers much larger and brighter than New Zealand’s representatives of the family. The larger species have given rise to a legend that trees sometimes rain down water, or weep. The theory was, or' is, that these trees, by their roots,' draw water from hidden sources deep in the earth. The fluid is surplus moisture produced by the grubs, and dropped to the ground. In some cases, the quantities are so great that from five to six dozen grubs fill a quart vessel in an hour and a-half. Livingstone found grubs in companies of six or eight, and estimated that a single grub in s. single night produced about three pints. Frog-hoppers, in their perfect stage, leap prodigiously. In doing this they use their hind legs almost exclusively. It has been estimated that if a man could leap to the same extent in proportion to his size he would cover 400 yards. The insects are helped in these feats by sharp spines, one or two of them stout and solid, the others smaller, formed in a cluster. By using these, they can take a firm hold of the ground. The common frog-hopper in New Zealand is prettily marked, but most members of the family are inconspicuous, and, apparently, commonplace. Under a fairly powerful microscope, according to the Rev. J. G. Wood, they spring into sudden beauty, shown notably in their wings, which are a network of membranes, like the network on the wings of a dragonfly. On a February afternoon .a member of the Lands and Survey Department at New Plymouth found Mount Egruont’s crater to be swarming with active, slender insects of a very dark shiny steel blue colour, and about an inch long, harmless if not interfered with, but retaliating with a rapidly-acting sharp stiletto when handled. These proved to be a species of spider wasp, allied to the Sphex wasps. They paralyse spiders with their stings, and store the bodies in celts for their 3 r oung to feed on when they -emerge from the eggs. As there was no obvious local purpose in the crater to account for such a multitudinous invasion, the only conclusion was that the insects had drifted there unwittingly. For the time being they were, apparently, only idle tourists, with no job of any sort on their limbs or minds, although one of the surprises of the mountain top is to find occasional large dark brown rock-spiders cvendn the lava-crags of the old crater brim. Mr C. Ferris, Wainui, near Gisborne, was instructed by the elder Maoris of his tribe that the octopus is a kind of epicure, choosing dainty food, and that what it feeds upon is delicious to the human palate. His own experience bears this out. In the stomach of a particularly good specimen of an octopus he found crayfish, pawns, sea-eggs, and crabs. Each kind of food was very clean, and could be identified easily. Even the different parts of the crayfish and the crabs had been stored in the pouch by themselves. He cooked the octopus and the food it had taken, and he and a European friend who came along found that they were very tasty. He mentions that there were no shells amongst the contents. When an octopus seizes a crab it does so from behind. The crab’s claws are gripped firmly by the suckers, and are held away from the octopus’s body. The crab is bitten into by the very powerful, horny jaws, and a fluid is poured out. This soon kills it. The crab’s shell is completely cleaned out, and is discarded, There is no reason for any 1 prejudice against the octopus as food. Ah far as diet is concerned, it is more wholesome than members of the crab and the lobster ; family, which, mainly, are scavengers, feeding on plants or animals, living or dead. Although the octopus is repulsive

in appearance,_ and is greatly dreaded, Mr Ferris, being an experienced fisherman, finds ' that it is harmless if taken in the right way. His plan is a simple one. Placing his hands between the creatures eyes and its stomach, he thrusts his thumbs and fingers deep in at the back of the eyes. The octopus immediately becomes limp, as if paralysed. It may be carried high and dry, but if it is not killed, and if the grip is relaxed, it becomes active again, and tries to make for the water. Still, an octopus is not the best creature in the sea to play with. A friend of Mr Ferris, Mr J. Edwards, when fishing for crayfish amongst rocks at Young Nick’s Head, across the bay from Gisborne, had a narrow escape from being taken under a ledge and drowned. The suckers are so strong, Mr Ferris states, that they quickly draw in skin and flesh.