CREEPING, CRAWLING

Evening Post, Volume CXV, Issue 72, 27 March 1933, Page 8

CREEPING, CRAWLING

EATING ALL THE TDIE

HORDES OF-CATERPILLARS

The present season is apparently an outstanding success from the point of view of caterpillars, native or the progeny of imported butterflies, and the reports published at intervals lately about them, being encountered in countless herds, hordes, droves, or flocks— whatever gregarious collective nova is the correct one to use for caterpillars in quantity—are in no way exaggerated. Why the caterpillars are not suffering from the depression like everyone else is a riddle of Nature. Something in the immediate past seasons may have been particularly beneficial to their multiplication; birds, usually ready for such succulent tit-bits may have temporarily gone ofi caterpillars as an article of diet; a thousand and one things may have happened to upset the normal balance of Nature. If but a tithe of these myriads of caterpillars survives* the perils that normally beset the cocoon stage, then the following butterfly and moth season should see the air crowded with these insects, and ready to start the vicious circle again— butterfly or moth, egg, caterpillar, cocoon, and back again to the beginning.

It is the caterpillar, of course, that doe's the actual damage, although the primary responsibility for it'lies with the butterfly or moth that lays the egg. The brownish-green caterpillar which is marching along the coast between Otaki and Paekakariki devouring lupins and much else in the way of green herbage that lies in its path, happens to be the offspring of a native moth and not an importation. This fact, however, does not make its depredations any the less serious. The destruction of the lupins, as has been pointed out, means the destruction of about the only vegetation which keeps the shifting sands in their proper place, and, with the lupins cleaned up, who knows to what else this caterpillar will nest turn itsiattention? That they invade the seaside cottages, and even infest the beds, is of small import compared with the invasion of garden plots and farm lands, with the resultant destruction of vegetables and crops. Hedges and even trees, it is stated, are already being denuded of their foliage, but as yet there seems no practical method of checking the caterpillars' march. UNEXPLAINED ARRIVAL. Probably much more serious for the Dominion from an economic point of view, however, is the rapid multiplication of the green caterpillar which, barring accidents or sudden death, from the beak of some early bird, is destined by Nature to turn later on in its career into what is familiarly known as the white butterfly. It is of small use now inquiring how this pest reached these shores. The -fact remains' that some eggs of it arrived in the North Island but a year or two ago (probably in some fruit from Honolulu). These eggs hatched into green caterpillars, which found abundant food for their voracious appetites, and the caterpillars after the usual larval stage metamorphosed into white butterflies, which quickly spread over the length and breadth of the North Island. They have now apparently crossed the.Straits, for a message from Nelson states'that a white- butterfly has been seen in that locality. If that is the case, one will soon be thousands. That a white butterfly has crossed the Straits under its own motive power, aided by a northerly wind, is not very probable: it is much more likely that some eggs were unwittingly transported across the narrow waters hidden on some vegetable or plant. AMAZING- APPETITE. The green caterpillar of the white butterfly has an amazing appetite for so small and slender a creature. While making short work of cabbages, rape, and such like crops—it. being on record that the caterpillars (number unstated) completely destroyed a crop of swedes covering 85 acres in five days— it is at no loss to find a meal when.its favourite vegetables axe lacking. Many a garden in the Hutt Valley can show dahlia plants' with but fragments of leaves left after but a few ,of the caterpillars have dined, and = many other plants, too, have suffered equally. Where the ravages of these caterpillars will stop it is difficult to guess. The trouble is that the white butterfly in the various stages of its existence seems to find the climate of New Zealand very congenial to the multiplication process, so much so that the cycle of its existence may be completed twice in twelve months, instead of once as is normally the case. There are apparently not enough birds to eat all the caterpillars or eggs, although the^ former must be choicer articles of diet than the more hairy native caterpillar that is consuming the lupins. Possibly the parasite which has been imported to combat the plague will triumph before long—this parasite being a microscopic wasp, not the wasp With the black v and yellow tail so well known to and cordially disliked by people in the Old Country. And possibly in the course of the next few years the white butterfly will disappear naturally, all its ea^erpillarish offspring having died of starvation owing to the unthinkable fact that every edible green leaf in the Dominion has been eaten. But, of course, before then —to paiht a black picture in as dark hues as possible—the caterpillars may have developed, a taste for stalks and tree trunks as well, in which case their reign will be prolonged. . ,