IN TOUCH WITH NATURE

Otago Daily Times, Issue 20918, 7 January 1930, Page 2

IN TOUCH WITH NATURE

WASPS AND THEIR WAYS. By J- DRUMMOND. F.L.S., E.Z.S. New Zealand’s shiny black mason wasp, Pison, is often wrongly named the masonbee. It belongs to the same interesting and famous order as the bees, the Hymenoptera, characterised by stiff membraneous wings, coupled together in flight by a series of minute hooks, and, in the females, by a complete egg-laying instrument, often specialised as a sting; but it is not a bee. It does not belong to the family of a common English wasp, Vesper,, nor of the hornet. This family, the Vespid®, has no representative in New Zealand’s native insects.

To counterbalance this somewhat strange lack, there has been accidentally introduced into the North Auckland district an Australian, Polistes, a genuine member of the Vespidas, living socially ~nd making beautiful papery nests. This uninvited guest from the Commonwealth evidently likes the kindly sunshine of the north, which doubtless reminds it of its native country. It is reported to be spreading south rapidly, although it does not seem to have crossed the boundary of Auckland province. Its original domain is a large part of Australia and the whole of Tasmania. For years it had for its second name “ Tasmaniensis.” In the latest insects “Who’s Who?” Dr R. J. Tillyard gives the second name as “ Hutnilis.”

New Zealand’s mason wasp, which is plentiful, has been brought under notice again by Mrs L. M’Connell. Prospect terrace, Milford, Auckland. “One of these insects,” she states, “ built its nest between two folds of canvas on a swing bed on my balcony. I heard a buzzing there during the past week, and finally discovered the nest. I asked my husband to destroy it, as we did not like to use the bed while it was there, and I did not know if the owner would sting or not. We then found that the nest was of clay, about five inches long, with compartments, and these, to my surprise, were filled with long-legged spiders. The hind part of the spiders’ Jodies was almost opalescent, like a tinted pearl bead. The spiders did hot seem quite alive. They merely moved their legs very freely when touched. They could not walk. When we shook thorn all out of the nest, two ordinary brown furry spiders were disclosed amongst the strange ones, and they also were comatose. The owner of the nest has returned, and is searching over the bed anxiously for iits home. Why were the spiders there? ”

It is easy to answer Mrs O’Connell’s question. The spiders were placed in the nest by the female wasp in order that when the eggs inside hatched the young wasps should have a supply of good fresh food. For this reason, the spiders were not killled, hut paralysed. The wasp favours the kind of spiders represented by the largest number in the nest. Failing to catch sufficient of these, she took no risks in regard to her young going hungry. She provided two spiders of another species. Her action in placing her favourite spiders in her nest is described as instinct; her_ action in catching spiders of another species as discernment; and in this _ faculty of discernment there is seen possibility of improvement in wasps’ position in the world. All wasps do not store Some store caterpillars, others store flies, but in their far-sighted-ness they generally work on the same principle, keeping mainly to the class of creatures they feel are best suited for their young.

There are a few species of wasps that provide their young with. dead food. They bring a little at a time,, returning with fresh supplies at intervals. Mrs O’Connell might have asked another question: Why does the mason wasp store paralysed spiders? The answer is that it believes that spider food is essential to its young, and that the food must not be dead. If it ,took home a live, vigorous spider, and went off to get another, the first spider, probably, would have walked off by the time the wasp got back. A judicious sting, which paralyses, but does not kill, ibieets the case. As Mrs O’Connell states, the spiders she saw could move their legs feebly; they could not walk, hut their bodies were as fresh and juicy as if they had just come from their own homes. In that condition, if undisturbed, they would have remained until the young wasps made their ' horrible meals on living creatures. Each spider would have lingered in torture until a large part of it was devoured.

Wasps seldom depart from the particular kind of living food they store. A wasp that stores spiders does not store flies or caterpillars; a wasp that stores flies does not store spiders or caterpillars; a wasp that stores caterpillars does not store flies or spiders. The explanation offered is that adult wasps' habits, to some extent at least, are dictated by memories associated with their youth. It has been suggested—the suggestion might be followed up in New Zealand as profitably as in any other country—that the explanation might be tested by rearing some young wasps on food different from the food provided by the parent, and discovering if the young, when they are grown-ups. will store their homes for their own young with the kind of food on which they were reared, or if they will observe the ancestral preference for spiders, caterpillars, or flies. Young wasps are not very fastidious. A mother s solicitude, not a preference by the young for a particular kind of food, causes the selection. Experiments in England show that young wasps will readily eat almost any kind of insect or spider food, if it is sufficiently soft.

An English mason wasp was seen making its clay cells, moistening the clay to make it plastic. Under close observation the wasp was seen to stop its work in order to visit the edge of a pond and renew its supply of water, which was carried in ite crop. At other times, it obtained moisture by sucking drops of dew and the white froth known as cuckoospit, produced by a beetle, which lives inside the froth. In this case, minute, transparent pale yellow wasps were hatched from the eggs. Each egg-shell spat along the'side. A little wasp, wriggling out, fell on or amongst the paralysed Caterpillars in the cell. It fixed itself on one by driving its very fine, sharp claws through the skin, and immediately began its bloodsucking operation.

A young wasp of this species, Odynerus callosus, changes its colour according to the colour of the caterpillar. If the caterpillar is green, the y« cua wo

comes a beautiful pale transparent green. If the caterpillar is brown, the youne wasp becomes a transparent amber colour. If a green young wasp transfers itself from a green caterpillar to a brown cater, pillar, it first becomes the colour of mud, and. in a few lionr.-;. amber The blood of a green caterpillar is green, and the blood of a brown caterpillar is amber. A young wasp’s colour is caused by the colour of its blood, which is seen through the wasp’s transparent skin. The colouring matter of the blood passes from the caterpillar to the wasp. In other words, the blood of the victim becomes the blood of the blood-sucker.

A Christchurch correspondent has sent a note on a brilliant reddish wasp, Salius wakefieldi, not a mason, but one of the spider-hunters, and the most brilliant wasp in New Zealand. “I watched it collecting a fat spider for its larder,” this correspondent writes- “ I did not sec the first attack on the spider, but was an interested spectator of the process of haulage over an asphalted length of 30ft. The wasp, pulling a weight obviously heavier than the weight of its own body, gripped the spider and pulled backwards at a fast rate. I stopped the wasp, which released the paralysed spider and walked round it with head high in the air. Then it gripped a leg and dragged the spider to the garden. It made a reconnoitre again with its head proudly held. It disappeared into a cleft in the ground, stayed there a minute, came out and grabbed the spider, but ignored the cleft. Once more he reconnoitred and finally dragged the spider into a small hole, from which emerged many wood-lice."