CICADAS—INSECT SINGERS

Evening Star, Issue 21073, 9 April 1932, Page 2

CICADAS —INSECT SINGERS

[Written by L. W. M‘C., for the ‘Evening Star,’] The warm days recently have resulted in the hatching of large numbers of our green cicada, usually known locally as locust, or grasshopper. Both local names are incorrect; the cicada is not even remotely related to either of those insects. The sudden appearance in hot weather, the mystery of the feeding habits, and the musical ability of cicadas have excited man’s interest from the mists of antiquity until the present time. Judging by the numerous requests for information Dunedin people are not uninterested in, these children of the sun. Probably in all literature no insect has had more attention paid to it, but there is still very much to learn about tho life history and habits of the New Zealand forms. Anyone may quite possibly add a further chapter to our knowledge by closely observing the local species, particularly as regards their food and natural enemies. Aristotle, the first investigator of the cicada and its habits, did his work so thoroughly that little more was discovered until the dawn of modern scientific research less than a century ago. Homer and Virgil frequently mention tho insect; some of tho Greek poets lauded it to the skies as the symbol of tho nobility of their race. “ They not only addressed poems to it and struck medals bearing its image, but they also ate it.” Aristotle declared it to be a great delicacy. It was, and still is, a common thing to keep cicadas in cages because of their song. This practice led to the early discovery that tho males also sang, information perpetuated in couplet by Xenarchus, an ungallant poet of Rhodes:

Happy the cicadas’ lives, For they all have voiceless wives.

Tho Latin writers, on the whole, paid it little attention beyond agreeing that the notes were repeated with ‘ ‘ irritating reiteration.” Tho Chinese for long have watched and admired cicadas, and have caged them the more easily to study their merit. “ They eat nothing belonging to earth and drink only doiv, proving cleanliness, purity, and propriety; they will not accept wheat nor rice, thus indicating probity and honesty; and finally (hoiv appealing to celestial conservatives) they appear always at a fixed time, showing them to bo endowed with fidelity, sincerity, and truthfulness.”

Some 1,500 species are widely distributed over the earth’s surface; those found in Now Zealand seem to be confined to this country. Any cicada may be recognised by the broad head, the torpedo-shaped body, prominent eyes, and characteristic wings, the front pair much longer than the rear. They arc usually hairless or almost so, but in New Zealand at least, where some species enjoy a wide range in altitudinal distribution, there is clear correlation between elevation and hairiness, the latter obviously a protection against the severer weather _ conditions. The mouth parts consist in the main of a tabular “ beak ” specially adapted for sucking sap, which seems to be the sole food. So f-r we have no evidence of direct injury to trees. It is possible that, whilst feeding on the sap of healthy trees, they may inject bacteria previously absorbed when feeding on diseased plants. If it were not for the song of the male few people would be aware of the presence of cicadas. This song is produced in what must be the most complicated organ of its type in the animal kingdom. If the under side of the abdomen of the male is examined a lid will readily be seen covering up the “ musical box.” On bending back the body a little a chamber becomes visible. In this chamber is a brilliant, almost transparent “ mirror,” and above tins again a tightly stretched membrane often referred to as the drum. On the drum are ridges to which are attached muscles which, if tightened, cause the drum to bend. Slackening the muscles causes the drum to spring back again with a clicking noise which, rapidly repeated, constitutes the song of the cicada. The mirror and chamber seem to act as resonators, increasing the volume of the sound. Why the males should make the sound is not known. So far as has been discovered cicadas have no cars, yet investigation in Now Zealand by Dr Myers and his wife would credit the insects with some appreciation of music. The fact that one species sings in chorus would seom to presuppose the ability to hear. Further, Dr Myers showed conclusively that a wide variety of song is uttered by closely related kinds, but that the structure of the sound organs docs not vary with the music. In other words, the chief variable factor lies not in tho instrument, but in the player. One famous, or perhaps infamous, foreign species makes a noise like a locomotive whistle. Perhaps.to the female this sounds as a whisper—“ a veritable sweet nothing.” The singing occurs mainly in the hottest hours of the day. Only one local kind (our ever sings before dawn. All others wait for the sun. Japanese species are evidently similar in this respect, as witness an Oriental poet;— “Lo! on the topmost pine, a solitary cicada Vainly attempts to clasp one last red beam of sun.” When not in use egg-laying apparatus of the female lies hidden in a groove in the abdomen. It is most efficiently designed for its special purpose of laying «ggs in the tissues of plants. As tno insect clings to a branch or loaf the ovipositor is thrust frequently through the bark, resulting in an unmistakable herringbone pattern. Many hundreds of eggs are laid at a time. Marram grass, cocksfoot, ryegrass, bracken fern, all kinds of shrubs and trees, even a hoe handle have been recorded as having eggs laid in them. In the case of the hoe the handle was so damaged that it had to ho sandpapered before being fit for use. When the young hatch they descend to tbo ground and commence a burrowing existence. They are enabled to burrow in the hardest soil by the aid of the front pair of logs, which are modified for cutting and digging soil. The length of time spent in this under-

ground stage varies and is naturally difficult of accurate determination. In the case of a well-known American species it is seventeen years. When fully developed the nymph leaves the ground and climbs up into tho sunlight, where it commences life. All soil is carefully cleaned ofl the claws and the nymph feels about on tho back of tho tree, grasping now here, now there till a firm hold is obtained. The skin cracks on the thorax, tho head is pulled back, and soon the perfect insect emerges, leaving the skin stuck on the tree. Several of these empty cases may be seen on the large hornbeam tree near tho bridge over Lindsay’s Creek in the Gardens. ' The adults have many enemies. In spite of their apparent strength they frequently _ fall victims to _ spiders through being caught in their webs. The larger dragon flies also prey on them. It is a spectacular sight to watch a giant dragon fly swoop and catch in mid-air a large cicada of much heavier build. Thanks to their slow, conspicuous flight, they make easy prey for birds. In the adult stage kingfishers and mackerel gulls among the native birds eat them, and kcas aro very partial to the nymphs. The sparrow, soon after its introduction, played havoc with cicadas, so much so that their extinction near towns seemed inevitable, But within recent years tho cicadas seem to be returning. Perhaps wo have here another example of the restoration of the balance of Nature, an accommodation to new conditions, a new wariness on tho part of modernised insects as regards bird enemies unknown sixty years ago.

To the Maori the cicada or tarakihi was tho sweetest singer of all the song birds. It was also known as the “ Bird of liehna,” this god being the lord of kindness and plenty—an allusion to tho fact that cicadas are more numerous in a hot summer, a time of good harvest. “ Like cicada chirping in the eighth month ” was the translation of a proverb meaning “ When there is much food there is also much talking.” One of the best known of /Esop’s fables is that of the cicada and tho ant. Those who believe in the common origin of folk-loro will find support in the Maori fable, especially when it is realised that we have no harvesting ants in New Zealand. “ When tho eighth month of the Maori year conies it is then that Tarakihi comes and clings to his ancestor Tane (trees).” In numbers countless they come and aro seen basking in the sun, while the clamour of their song is like unto the crackling of a reed fire. “ What truly is niy delight? It is idling and basking in tho sun on a tree branch and just clapping my wings.” Somewhere down at the base of tho tree is a very' soft song wing by Popokorna the ant. In the beginning tho ant had spoken to tho cicada in this wise: “ 0 friend, let us bo diligent and collect much food during tho warm season even that we may retain life when the cold of winter comes.” But the cicada replied: “ Nay! Let us rather bask on the sun-warmed bark of tho trees and sing a merry lilt.” When in after days the warmth went out of the sun, when ice covered the waters and frost the ground, then it was that tho cicada perished of cold and hunger. But the ant, how snug is ho in his sheltered home well stocked with food.