ENEMY OF HOUSE-FLY.

Northern Advocate, 4 September 1913, Page 2

ENEMY OF HOUSE-FLY.

ARCH-ENEMY DISCOVERED IX FIJI. (By Suva Correspondent of "Sydney Telegraph.")

The little brown ant. in Fiji has at last come into his own. He has long been looked upon as a curse, but is proving to be a blessing in disguise. The remarkable freedom from houseflies in Fiji at this season is now understood. The great majority of them are destroyed by the ant while in the egg or larvae stage. The discovery is of remarkable interest and importance to all tropical countries.

The scarcity of house-flies during the present dry spell has been a matter of common remark in Fiji. The open manure pits that are to be found on every side appear to offer ideal places for the flies to breed, and still very few flies are to be found, even about the stables.

Dr. J. F. Illingworth, Professor of Entomology in the College of Hawaii, who is visitirfg the islands in the interests of the Colonial Sugar Refining Company, recently began investigations at Nadi to ascertain what was holding the Hies in check, and if some parasite could be bred, when its great value to mankind would at once be recognised. Early investigations showed that there was a remarkable scarcity of maggots, even in the unprotected manure pits. Ants, being everywhere in abundance, were not taken into account at first. Soon, however, their great numbers over the fresh manure led to closer observations and the discovery that they were carrying the eggs and newlyhatched larvae of the house-Hies. The egg or young maggot was held by one end and elevated above the head of the ant. while he was making his way over the uneven surface of the manure. It will be easy to understand why this discovery was not made before when we recognise that the egg of the fly is only about l-25th of an inch in length and the newly-hatched maggot only slightly larger.

Further observations revealed the fact that the ants destroy larger maggots of the house-fly in great numbers; in some cases even when they have reached full size. The rapid heating of the manure, or the myridas of mites which are to, be found in the manure irritate the maggots so that they come to the surface from time to time. If they appear among the ants, which are swarming over the surface, they are at once pounced upon and after a rough and tumble the superior numbers of the ants win the day, and the maggot is dragged off to their nest.

In one experiment five full-grown maggots were dropped down among the ants at one time; within 20 minutes the maggots were conquered, and in 10 minutes more were being drawn into the nests of ants.

The wonderful reproductive ability of the house-fly, even in cold countries, where they are killed off by the winter, suggests the unthinkable hordes that would plague us in a warm country like Fiji if they were not held in check. Dr U 0. Howard, in his volume on the house-fly, estimates that one female fly that escapes the winter, laying 120 eggs in April, would result in 5,598,720,000,----000 adult flies by September 10 if the conditions were perfect for reproduction. The number is unthinkable, much less can we imagine what, the increase would be in a tropical country where breeding goes on the year round. The indications are that the little brown ants are the principal factor in the destruction of the great, majority of house-flies in warm countries.