1500 SPECIES OF MOTH FOUND IN N.Z.

Press, Volume CXIV, Issue 33514, 20 April 1974, Page 12

1500 SPECIES OF MOTH FOUND IN N.Z.

(Contributed by the Canterbury Museum)

Of the 200,000 species of moths and butterflies known to science only 18 species of butterfly have been recorded in New Zealand. This country is rich however in moth species — 1500 are know n to occur here.

An excellent way of adding to our knowledge of moths and butterflies (collectively known by those who study insects as the Lepidoptera) is to raise them in captivity. During their life history the Lepidoptera pass through four stages: the egg. the larval or caterpillar stage, the chrysalis, and the adult. The eggs, usually button or bottle shaped, are laid singly or in clusters, often on the surface of twigs or leaves, and they take one to two weeks to hatch. The eggs hatch out into worm-like larvae or caterpillars in a phase of the life cycle that rarely lasts the Lepidopteran’s life cycle On reaching maturity the caterpillar pupates; that is. it enters the third stage of the Lepidopteran’s lifecycle —the pupal or chrysalis phase. The mature caterpillar builds a cigar or

barrel-shaped cocoon, which serves as the pupal chamber. Its walls are tough and horny and they are sometimes made up of soil particles or other materials held together by saliva.

Once the caterpillar has completed its cocoon it is referred to as a "pupa.” Although from outward appearances it seems inactive. it is undergoing many internal changes. The organs of the caterpillar are being broken down and reassembled to the adult pattern. In some butterflies (for example the monarch) the pupal stage lasts only about 10 days, while in other species it is two or more years. Plainly visible Many features of the adult are plainly visible on the pupae—the wing cases, positions of the legs and antennae, for example, and (just before the butterfly or moth emerges) the patterns and colours of the forewings. The first sign of the butterfly or moth emerging is a dorsal split in the pupa, and about an hour later the wings are sufficiently expanded, and hardened for flight.

Three things distinguish moths from butterflies. Whereas butterflies fly about in the day, moths are usually seen on the wing only at night. Butterflies usually rest with their wings held vertically above their backs so that the upper surfaces of the wings are concealed, whereas moths often rest with much of the upper surfaces of the wings exposed. And in butterflies the antennae, or feelers, are enlarged at the tips into knobs, while the feelers of moths resemble feathers. Wing colours Numerous functions have been ascribed to the colour patterns on butterfly wings In many species the disruptive colours on the wings break up the shape and outline and provide camouflage against enemies or predators. In some species there are special blobs of colour on the wings—deflection spots —to misdirect the attack of a predator. In other species the wing markings function as eye alarms to scare predators off. Some species have warning colours that advertise a repellant taste or smell.

The wide variety of butterflies on display at the Canterbury Museum illustrate some of these points. An interesting feature of the Lepidoptera is their mouth parts, which may be likened to a tube or proboscis. When the butterfly lands on a sugary solution (for example nectar), the proboscis is unrolled and the sugary solution is sucked up by the pumping action of the gullet. —G.A.T.