Builders, Borers And Biters SUMMER INSECTS II.

Auckland Star, Volume LXX, Issue 35, 11 February 1939, Page 7 (Supplement)

Builders, Borers And Biters SUMMER INSECTS 11.

Last week we mentioned that the absence this summer of really hot days had resulted in a season of comparative quietness as far as some of the better known "household" insects are concerned.

One whose absence we do not exactly deplore is the mason bee. Although commonly called a bee, the New Zealand insect is a wasp. It belongs to a class of insect known scientifically as hymenoptera (the name k derived from two Greek words meaning membrane and wings). All insects of this group have four veined gauzy wings. Another class of gauzy-winged insects has two wings. It is diptera meaning two-winged. The daddy-long-legs and the mosquito are wellknown members of this classification.

Those of us who are familiar with the energetic buzzing of the mason wasp—(l will use that name, and then we will know the insect referred to, as the more correct name of "fly" would be misleading)—l know the annoyance that usually arises from having to poke away at fairly inaccessible corners and crevices, keyholes, window-ledges and ceiling mouldings in order to dislodge the clay nest.

However, as la often the case with so-called "unpleasant" insects, the mason waep is a clever worker and builder, and a study of its habits cannot but increase our admiration for the wonderful ways in which soin? small creatures work—even though it may not increase our desire to have it building a nest on the bedroom ceiling, or 011 the door-ledge in the dining room!

'Hie wasp carries inud or clay in its inouth, and gradually builds up its home, one cell at a time, until four to six of these oval compartments have been completed. Working on the construction of one cell at a time, the wasp fills each with a collection of spiders which have been previously benumbed (but not killed) by the sting of the collector.

Into the body of just one spider in each compartment the female wasp inserts one egg, from which there later emerges a creamy-coloured grub, who now has a convenient supply of fresh food, because the spiders are not yet dead, but just benumbed. I suppose the newly-hatched insect knows what to do with the spiders that it finds packed so thoughtfully in its own little room, and it probably makes short work of the tasty provender.

After a satisfying meal, the grub prepares for the process of metamorphosis, during which it produces wings, and emerges from the silky cocoon which it spun around itself before turning into a brown "pupa." Then we know that there is at least one more mason wasp that will probably make its presence felt and heard as it proceeds to make a clay nest for itself some sunny day in the future.

8y... Olga P. Burton.

Another 6unnner visitor to houses is the hu-hu beetle, which sometimes makes its way inside during the hot months in order to lay its eggs, usually on some wooden surface. When laid out of doors the eggs are placed under the bark of trees, or in a crevice. The beetle Itself is unmistakable, being brown, and of considerable size—about two inches long and half an inch wide. If the eggs are laid on the bark of a tree, the newly-hatched grub bores its way into the tree for some inches, using its powerful jaws for the process.

If by nothing else, the unwelcome mosquito is known to all of us by the humming noise it makes at night —a sort of vibrant "pinggg," which is made as the antennae of the male of the species vibrate quickly while the insect is in flight. The unpleasant biting process, and sucking of blood that raises the well-known "mosquito bite," is the reputed work of the female, who is of quieter habits; but, when we are in bed on a hot summer evening, with windows wide, and all liplits extinguished so that too many insects are not attracted, I don't think we bother pausing to decide whether it is Mr. Mosquito or his wife who come humming and "pinggg-ing"' round our heads, so that we either pull the sheet over our heads or else make frantic and futile blows in the air in the hope of striking the unwelcome visitor.

Of course, if we arc very wise, we will be prepared and apply citronella or some other, recognised safeguard. Perhaps I have been fortunate this summer, but not once have I been troubled by the molestation of these nocturnal visitors.

Stagnant water is, of course, the recognised breeding ground of the mosquito, for the eggs are laid in clusters on the surface of still water. Froia the eggs there emerge small creatures known as "wrigglers,"' which live in the water, coming to the surface to breathe. But as the breathing apparatus is located in the tail of the wriggler, the process of

breathing consists in putting not the head but the tail above the surface of the water!

On the next stage or growth, however. the breathing organs develop, something like small ears, at the side of the head, which is now much bijrger than i*t wae iu the wriggler stage. After about a week at the second stage of growth, the potential mosquito becomes inert, floating upon the surface of the water in '"pupa form for about three days, before the fullgrown mosquito emerges. I wonder if you have ever noticed the way in which some small birds and dragon-fiie<s skim over the surface of still water? They were probably in search of either eggs or mosquito pupae, upon which they feed in large numbers, and for this reason alone (quite apart from their beauty and harmlessness) we should be pleased to see dragon-flies skimming so gracefully near the water.

11l tropical countries, constant warfare is being waged against the Anopheles mosquito, which on account of transmitting the dread disease of malaria is well known as an enemy to man's health and life. The malariologist to the Government of Zanzibar is a New Zealand doctor, and on his recent return to his native land he gave an interesting account of the steps being taken to combat the ravages of this mosquito, which breeds in swamps and must therefore be attacked there if its forces are to be reduced. Methods used in this direction included the draining of swamps, spraying the marshes with poison, oiling .the water, and clearing away undergrowth to allow winds to blow through.

By the first method, trees such as the eucalyptus are being planted, these gradually drying up swamps that had previously been as much as five feet deep; for spraying purposes, parte green, an arsenical compound in the form of fine powder is used,

while by the third method the larvae of the mosquito could be prevented from reaching maturity when a film of oil—a mixture of paraffin and crude oil—was poured on the water, thus preventing them from breathing.

As a result of these and similar activities, the malariologist states. Zanzibar had been practically freed from the dread plague of malaria, the menace to man's well-being, of the Anopheles mosquito being greatly reduced.