IN TOUCH WITH NATURE .

Otago Daily Times, Issue 20582, 4 December 1928, Page 2

IN TOUCH WITH NATURE .

THE MANTIS’S EGG BASKET. By J. DstrwifoND, F.L.S., F.Z.S. Late at night bn April 25, 1926, Hr B, D. Pritchard, Norman’s Hill road, Onehunga, had the interesting experience of watching a mantis, a large bright green insect fairly plentiful in gardens, make its egg basket. The egg basket often may be found on a twig, a stem, or a paling, stuck close to the wood. The insect, is seen less frequently, its colour giving it protection and concealment amongst foliage. Mr Pritchard caught a female mantis in a rhododendron busE at 5 p.m., placed it in a box with a glass front, kept it under observation, and wisely made notes of what he saw.

After the eggs had been laid the mantis, hanging in a horizontal position beneath a straw, and supported by the four hind legs, began to produce a white, frothy substance like whipped white-of-egg. This was allowed to come into contact with the lower surface of the straw. The fore limbs and the Wings were folded, and appendages, called the cerci, on the last segment of the abdomen were extenod sideways, as if to escape contact with the moist substance. A yellow egg soon was seen to have been laid vertically downwards. Parts of the ovipositor, an organ used for depositing eggs, went up and down the egg during deposition, as if to apply a coating of a clear liquid over its surface. Six eggs were laid and treated in this way. Three of them were placed towards the insect’s left side, and three to the right side, meeting at the middle to form a single layer. The eggs seemed to bo directed into their relative positions with the help of leaf-like projections between which they passed. The insect’s bodily stress was noticeable on the straw, which responded to the rhythmical movements of the insect’s body. One of the legs occasionally was suddenly removed from the 'straw, apparently on account of the muscular strain.

With a circular movement of the rear segment of its body, the insect continued to apply a layef of the frothy material over the layer of eggs. A series of peculiar contractions of the abdomen seemed to be connected with the formation of a prominent ridge along the top of the egg basket. One of the little projections was formed ir this way on the completion of each layer. About 12 repetitions of this sequence completed the task at about 12.30 a.m. The eggbasket then was three-quarters of an inch long, a quarter of an inch wide, and a quarter of an inch deep. The finishing of the structure was a fairly long process. Progress seemed to be slower then than previously. Finally, the body was thrust downward from the frothy material, and the insect, in a short time, crawled slowly and unsteadily from th straw. The feet were not seen to move during the building operations; the necessary forward movement was made by means of the fiexibleness of the joints of the legs. The end of the egg basket was at a point where the bind feet had been placed.

For 13 days after that activity, the mantis took no food. "During the night of the fiftieth 1 day, June 14, it made a smaller egg basket on the ridge of the first,one. It took no food during the remaining 20 days of its life. On the •eighteenth day, it held a house fly for 30 minutes, but it allowed the fly to escape. Mr Pritchard concludes that its desire to protect its eggs was stronger than its desire for food. - It died on July 6, after having been under observation for 70 days. When the egg baskets were examined on January 24, 1027, they < seemed - to he invaded by small insects. On dissection, the larger egg basket was found to contain about 70 mantids, partly developed. All were dead and- partially dried, a condition caused, possibly, by being subjected to bright sunlight and warm temperatures, ranging from 67 degrees to 90 degrees Fahrenheit on September 10, 1026. The eggs in the smaller egg basket showed signs of early decay. Apparently they were infertile, no changes being found in them, even after 224 days.

A large and very handsome slug sent by Mr F. E, Piper, Makairo, Pahiatua, has been identified by Mr E. F. Thompson, assistant curator of Canterbury Museum, as the great slug of the Old Country and of Europe, Limax maximue, which ranks amongst New Zealand’s introduced animal life. Mr Piper , found it on the door of his washhouse one evening. These slugs hide during the day under stones and dead leaves or in places that are dark and moist. As their vegetable food seems to be mould in preference to garden vegetables, they do little damage, but are carnivorous, and they have been convicted of cannibalism. When three were kept together in a box, one of them was found to have been eaten, only its tail being' left. This act was not dictated by lack of ordinary food. Other members of the species, making their way into dairies, have fed on raw beef.

Kept in captivity with a young slug of another species, a great slug attacked it repeatedly, denuded it of its slime, and gnawed pieces off its body. The great slugs’ sense of smell, probably, is the most important sense they possess. It is more important than their sense of sight. One rainy day. in the botanical gardens at Toulouse, two great slugs appreached a rotten apple from different directions. The position of the apple was changed several times. In each case it was placed at a sufficient distance to ensure that they could not see it. They always hit it off correctly, after they had raised their heads and had moved their tentacles in every direction. The apple then was held above the slugs’ heads. They soon discovered where it was, and raised their heads, lengthened their necks, and tried to find a solid body on which to climb to the apple.'

The respiratory organ of this slug, that is, its breathing organ, is on its right side. Its mouth is a horny jaw, with a cutting edge, produced- into a kind of beak in the middle. The action of its teeth has been described as like the action of a cutter on a lawn mower. The fixed jaw corresponds, to the bar against which the cutter clips off .the grass.

“ For the past two or three years,” Mr L. M. Monckton wrote from Waipukurau on November 11. “a pair of grey warblers have built their nest in the same place in the garden, in a macrocarpa trees, about 10 feet from the ground. About two weeks ago the nest contained two eggs. Then a storm broke its lashings to the bough, and it was found under the tree, full of water. We tied it on to the tree again with string. Two days later we found that it contained, four eggs. On November 10 these eggs were seen on the ground under the tree, broken. Looking into the nest, we saw one of the grey warblers sitting on the egg of a shining cuckoo. Prevously I thought that the young cuckoos evicted the grey warblers’ young. In this case, evidently, the parent cockoo left nothing to chance, and took out tha eggs of the owner of the nest to make room for her own egg. The grey warbler must have very strong maternal instincts, as nothing seems to make her desert her nest.”

Sometimes a grey warbler’s young are found in a nest with a young shining cuckoo.’ In other cases, shining cuckoos follow the practice Mr Monckton has 1 they remove the eggs of the owner and leave their own eggs to be hatched ny the foster-parents. An early observer