Ugly But Harmless

New Zealand Herald, Volume LXXIII, Issue 22498, 15 August 1936, Page 10 (Supplement)

Ugly But Harmless

New Zealand's Giant Wetas WINGLESS RELATIVES OF THE CRICKETS Specially written for the New Zealand Herald

By R. A. FALLA

INSECTS are much the same all the world over, and except for the greater size and brighter colours of many tropical species, they show a conservative similarity in temperate zones. The butterflies, beetles, flies, ants and bugs of New Zealand all have their counterparts in the Northern Hemisphere. Here and there an insect may show distinctive features like the long proboscis on our giraffe weevils, and one or two primitive families have their headquarters hero. Conspicuous among these aro the large and

of this kind is unlimited, for in the ease of tho wetas alone only a mere outline of lifo histories has been rt> corded. Tho species of weta so far mentioned aro of medium sizo, an inch or two in body length, and several inches including hind logs and Smaller stages will also bo found in any species for in the primitive ordei to which wetas belong the young insect hatches from tho egg as a small edition of the adult and grows by successive stages. One or two species, however, are veritable giants among insects. A heavily armoured largo kind is th* 1

ugly insects which we call by their Maori name, weta. If relationship for the wetas is sought among the world's insects it is to be found with the crickets, the Australian king cricket and the New Zealand wetas being giant wingless representatives of that family.

rugose weta found in the Cook Strait region, and it is exceeded in size by the great forest weta of more northerly distribution. This one has an over-all length of about a foot, and is said to have been an agile tree climber. It if now many years since a specimen wa* reported, and it seems only too likely that this interesting species has been exterminated by some one of the man) imported animals, probably by rata.

The common species in tho Auckland district is the-big-headed weta, a name that is more appropriate to the male than to the female. The male has a disproportionately large head and powerful jaws, but in spite of his fearsome appearance he is a comparatively harmless insect When tunnelling in a treestem he probably works in advance of the female, leaving her little actual boring to do. It is usual to find pairs of wetas together in the same tunnel, where they remain throughout the day, pursuing their normal feeding activities at night. Vegetation provides their principal food, both leaves and shoots being eaten. Loft to themselves wetas on the move are deliberate and leisurely in movement, exploring the field ahead with their long waving antennae and dragging themselves along as if with difficulty. But at times the situation calls for more agilit.v and wetas can then leap with ease This habit often lands them through open windows at night, and at daybreak, seeking shelter, tho insects may hide themselves in tho nearest cavity, which happens so often to bo the toe of somebody's convenient shoe

A year or two ago the writer was one of a party visiting the Poor Knights Islands, off the north-east coast of New Zealand, and on that occasion we found large wetas like the giant forest species Here and there we found them perched motionless on branches of teatree, and they offered no resistance when captured. It is only fair to add that the peaceful specimens captured on this occasion were all males, and that two females taken on the same island two years later showed much more enterprise in their attempts to escape. The Poor Knights weta turns out on examination to differ slightly from the species once found on the mainland It is to be described as a new species, and the giant forest weta remains to be rediscovered.

All the wetas described above are vocal to a slight extent. The common species makes a grating sound by rubbing the thighs of the hind legs, which have a granular surface, against o small series of ridees on the third abdominal segment. The so-called cave wetas, however, are deaf and dumb as well as wingless. These exceedincK long-legged insects belong to a different family from the true wetas, and would be better distinguished by the name cave-locusts, which is applied to them in Australia They associate in largp numbers in caves, old tunnels and in hollow trees, and it would bo interesting to know how they live. Very little seems to be known about them, even on the simple subject of their diet and feeding habits In the first place ii would probably be found that the des cription 'deaf and dumb" is not accurate, for although they have neither ears nor sound-producinjr apparatus, the respective functions of these organs may well be performed by the antennae, which are of exceptional length and consist of more than 550 segments.

The herbivorous feeding habits of wetas have generally been accepted as universal, but Mr. W. W. Smith, of New Plymouth, than whom there is. in New Zealand no more observant naturalist, has recorded carnivorous habits in one of the ground wetas. Some years ago on the Mount Egmont Forest Reserve he happened to notice a weta crossing a shingly path carrying a large native blue-bottle fly. Testing his observation by experiment, as every observer should do when possible, Mr. Smith captured several wetas and provided them with both plant food and more blue-bottles. All the latter were caught and eaten, but only at night or on wet days when they were slucgish; the vegetation was eaten as well The field for olisorvational work