THE NATURALIST

Otago Witness, Issue 3764, 4 May 1926, Page 80

THE NATURALIST

THE EARWIG: IS IT A DAN= GEROUS PEST?

By

CRYPTOS.

(Fob the Witness.) Dunedin gardens are well supplied with a variety of pests. One which of late years has be*n increasing in abundance, much to the disgust of gardeners and housewives, is Forficula auricularia—better known as the common earwig. Although rare in most parts of the world, in Europe, and especially in England, no insect is better known, being abundant in all gardens and cultivated places. In certain seasons it not infrequently enters the houses, and falls victim to the wrathful housekeeper. In New Zealand, according (o the Hon. G. M. Thomson, the first ear'.rigs were reported from Ashburton by Mr W. W. Smith in 1900, and again in North Canterbury in 1908, while they v*.re also reported to have been observed in several places in the Wairarapa district. Since that time they have become more widespread, and are very common, es]«eeially in Dunedin, Palmerston, Christchurch, Waikari (N.C.), and Oust. For those who live in the above localities the earwig requires but li Me describing. It is an elo”gated insect some three-quarters of an inch in length, and a good type of the winged earwigs. The fore-body consists of three thoracic segments, the triangular head bearing the long, filiform antennae, two large facetted eyes, and a typical insect month, a second or middle segment bearing one pair of legs, and a third segment bearing two more pairs ot logs and covered by the folded wings which project beneath the tegmina or leathery wing covers. The abdomen, or hind body, is elongate, and formed of ten segments in the male, and eight in the female. The body is always terminated by a pair of horny, pincer-like “nippers,” vary in shape according to the sex. The colour is a metallic brown, while the wings and legs are of a paler yellowbrown. The head, too, is lighter in shade than the abdomen. Many species of earwig are wingless, those species which have wings use U'**n hut rarely. The type common row»d Dunedin does fly occasionally, however, and the writer has had at least two Casas of flight brought under his notice just recently. The wings themselves are wwtfiy of attention, both as regards their and the manner in which they are folded up in repose. When expanded they have a shape curiously suggestive of the human ear, and in structure consisting of a delicate membrane stretched between radiating ribs of a horny nature. These wings are. remarkable for their d«licacv, and are folded up in a more interesting and complicated manner than are those of any other insect. Briefly, they close first like a fan, the delicate membrane falling into folds between the ribs; next, with a transverse fold, as though the c.l..&cd fan were folded by breaking all the ribs and turning the outer edge in to the handle ; and, finally, by this being repeated in the reverse direction, and the whole tightly packed under Mie cover. It should also be remarked that no part of the delicate membranous expanse of wing is exposed when the wings are folded. Although the whole •wing does not lie under the tegmina or wing cover, the portion that projects is of a hard nature, and coloured much like the tegmina itself. it is quite a mystery why earwigs should fold, their wings in this complex lAauncr. ft is probable that the majority of individuals never use their organs of flight or even go through the complex po*»ccss <*f unfolding and folding them. I he pair of forceps with which the bodv is armed at its extremity forms another character almost peculiar to earThese forceps vary much in the aHjarent genera, and sometimes attain very large and distorted shapes. They sometimes for helping to pack the wings, but so far their greater importance to the insect is somewhat obscure. No doubt they give their possessors an imposing appearance, and may be of some little advantage on this account. They are occasionally used for cJeicnce, hut the nips they give are not of a formidable character, and probably are mei3 ,f blufT” armaments. The name “earwig” is said to be due to the idea that these creatures are fond of nenel rating into the cars of persons, preferably babies, when asleep, and hence they are often dreaded, owing to the fear that they may penetrate even into the brain. There does not appear to be on K'eord a single instance that would justify such a dread, or even the belief that they knowingly enter the ears. It is, however, a very curious fact that a superstition, of the kind we have mentioned occurs in almost every country where the common earwig is abundant. It is known as orhon-worm” in German, as “pcrccoreille” in French, and so on. The expanded wing, ns i have mentioned, is so very much like the human ear in shape, that one is tempted to suppose thin resemblance may in former ages have given rise to the notion that the earwig had some connection with the human ear, or that the name, at least, was derived from ear wing. This explanation, however, is rendered very improbable by the fact that the earwig in scarcely ever seen with its wings expanded, and that it is a moat difficult matter to unfold them artificially, ■o that it ii unlikely that the shape of

4 -he wings should have been observed l.\ •-~Uc untutored ’ , , . The earwig has a very station with the gardeners at home, who rcg*?*. it as an injurious insect, but some authorities think that it is probable that it is sometimes made the scapegoat for damage dene by other pests. Even at home there is no doubt it appears to be fond of sweet things, for it often makes its way into the interior of fruits, and nibbles the petals and other delicate parts of flowers and vegetaDies. Camerano, however, states that the specimens he kept in confinement preferred dead insects rather than the fruits he offered them. Ruhl considers the earwig to be fond of a carnivorous diet, eating larvae, small snails, etc., and only attacking flowers when these fail. It has a great propensity for concealing itself in places where there is only a small crevice for entry, and some people again consider that its presence in fruits and flowers is due to this fact, rather than to any especial fondness for the juice. In New Zealand the earwig is certainly destructive to a certain extent. In the writer’s garden they are always to be found in the corollas of a nasturtium, and the specimen in front of me at the moment was lurking in that place. The Hon. G. M. Thomson says, concerning the ■New Zealand varieties: “These insects are most destructive to vegetables, flowers, and fruits, and even penetrate into houses and devour all starchy and saccharine food materials. They are voracious feeders, and are especially fond of corollas of flowers, so that they' are a great annoyance to gardeners. Occasionally they visit flowers for nectar rheir destruction of fruit is chiefly that which has fallen on the ground, or which grows near the ground, like strawberries." Despite this, however, it may be that the destructive powers of the earwig are even in New Zealand. The tact that they are considered a dangerous pest may have resulted in blaming them for more than they deserve, and it is 1 ° f a m ore careful obsertheAr habits mi K ht res,, lf in a from the ,on « ,ist of