INTELLIGENCE.

Waikato Times, Volume 102, Issue 17133, 21 June 1927, Page 10

INTELLIGENCE.

HAVE INSECTS GOT IT? ADDRESS TO FRUITGROWERS. The extent to which it is advisable to apply the world’s collected science tiflo knowledge to New Zealand, in regard to plants, insects, and animals, is so limited, in fact, that local research alone can supply facts upon which it is safe to work. With Dr. Marsden at its head, the new Government Department of Scientific Research has an immensely wide held to cover, but the value of the -work will be more apparent to future generations than it is at present, because "the foundations will have been laid for the compilation of facts which will enable students to commence investigations in narrower fields, with more hope of ultimate success.

If all scientists could present their problems with, the same raciness and breezy humour as Professor Tiltyard, public sympathy with research would undoubtedly assist more in promoting it than it does at present. Ilis description of the difficulties experienced in introducing a suitable parasite for the earwig, when he addressed the Fruitgrowers’ Goafcrence on Wednesday, contained all the elements of a successful novel, and was half detective story, half romance. Earwigs, like .many other insects and things, have thriven in New Zealand enormously, and constitute almost a plague to orchardists in Canterbury and Otago through their fondness for the best of ripe fruit. Common methods of destruction fail to keep down their numbers, and so a parasite was sought. It was in the adventures of Professor Tillyard, the earwigs, and the parasites that both humour and the interest which attaches to all deadly struggles, with a little domestic touch thrown in, provided a thoroughly entertaining tale. Launched Out on New Lines. New Zealand has launched out on new lines in many directions, compared with tiie Old World, and almost any set of statistics can be used to show that the innovations have resulted in improvements on the Old and hitherto accepted methods tried here and discarded, chiefly because local conditions differed widely from those in older countries, but. in the field offering the highdfct opportunities for fresh discoveries, that of scientific research, it is only recently that the importance of investigation of the possibilities has been recognised. What research has been done has proved conclusively that New Zealand conditions vary widely frorp those in which scientists have hitherto carried out their work, and that introduced insects, animals, and plants adapt themselves so rapidly lo New Zealand conditions that, while existing information, and the methods by which it was acquired, are helpful, they all too frequently turn out either not to apply at all or to merely indicate closed avenues.

Leaving out the names of the parasites, which Professor Till yard certainly pronounced, a sentence at a time, hut wisely forbore to spell, as his time was limited, it appeared that Micro were two parasitic flies which had proved of value in Europe in diminishing the number of earwigs. One of these laid an egg, in the orthodox way, but the other laid a live larva. The first showed a remarkable instinct or intelligence in its plan of campaign. Smelling fully round, it selected a fruit or leaf, dandelion leaves being a special delicacy to earwigs, which had been already nibbled by earwigs, and laid its tiny black nothings, on the nibbled spots. Later along came the earwigs, and nibbLed the leaf or fruit, gobbling up the eggs in the process. Once inside the earwig the egg, particularly immune from digestion by the punyintestinal efforts, of the earwig, hatched out into a fierce and ravenous larva, which forthwith proceeded to eat its host out until only the hard shell remained. The other parasite with an endless chain name laid instead of an egg, the live larva itself, and Ihe latter was equipped with a special boring plant for the purpose of feloniously entering the earwig through its shell, which accomplished, it proceeded in i manner similar to the first.

The method of testing out the efficacy of the parasite, which had given excellent results in Europe, was to introduce the earwigs to slices of apple or potato, allow them to feed, and then remove them and introduce the parasite flics to the same cage. Later the earwigs were again introduced to the cage, and the eggs had almost invariably been, gobbled up with the food.

Marvellous Intelligence.

The European earwigs in New Zealand showed an intelligence that was marvellous. Though, as a race they had been separated from the ravages of these particular flies for a long time, not in one instance did they eat the eggs deposited by the flies in the experiments. Each egg, miscroscopic though it was, was carefully eaten round, and left standing on a little pyramid.

Failing- in this, the larvae of the fly which laid the live larva was introduced to a cage of some thousands of earwigs. They immediately evinced the greatest l'ear, running madly about to escape the larvae, and the Cawt.hron scientists left the situation to develop, feeling satisfied that a goodly percent:age of casualties in the earwigs would follow. But there was not one. Whether the earwigs, which are elastic-bodied creatures, and gymnastically quite capable of picking a larva off any part of their bodies in their jaws had killed the larvae, or whether, owing to the discrepancy in the laying seasons of the flies in New Zealand, the larvae found the shells of their victims too tough, on account of their more advanced age, could not he determined, but the attempts were a failure. An attempt will be made to retard the development of the insects so that the requisite softness of the earwig shell may coincide with the arirval at adolescence of the rapacious larvae, and if it is discovered that earwigs arc then susceptible to this gentle persuasion, the larvae may prove useful after all.

“Have insects intelligence ?” asked the Professor. “If you put a difficult problem to two children, and one of them, same to light .with an ingenious solution, and the other remained dumb, you would say that one of them had intelligence and the other had not. What can one say in the case of the earwig, which so far has resisted our attempts with these two parasites so well that the results have been far from satisfactory. If the earwig has more intelligence than the Department of Research, then it will win. What it has demonstrated so far proves it a worthy foe.”