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February 18, 2019

Less rains now, and the dreaded housefly is back

AFRICAN TREASURE: Pastoralists with their herd of animals. Right, cows in the market. Photo/STEVE KINUTHIA
AFRICAN TREASURE: Pastoralists with their herd of animals. Right, cows in the market. Photo/STEVE KINUTHIA

The rains seem to have subsided slightly. For the last week, our area has not experienced the heavy rains that have continued to pound other areas of the country. Indeed, few areas are now reporting heavy rainfall. But the July cold has come earlier than usual. We are barely at mid June and the biting cold is already with us. I realise how difficult it is for the weatherman to be right when predicting the future for the country as far as the weather is concerned. It has become totally unpredictable. What is most predictable though is the aftermath of the long rain season, especially in our area, which borders the pastoralist Masai community. The grass has come back in plenty, the cows and goats that survived the dry season are regaining their health in style, and the people’s enemy number one – the housefly – has reappeared with so much zeal they don’t sleep at night!!

The old adage has it that none of us is exempted from death and taxes. But we, naturalists, might add another – flies. Buzzing at the sunny windows and running after their shadows, hovering hungrily over the dinner table – flies are so inevitably part of us that most people, especially those who keep domestic animals have come to accept them casually. In this part of the world where there is little pest control. This indifference costs more than we tend to assume. We pay for the indifference with diseases like cholera, dysentery, typhoid, trachoma, and others. Musca domestica, the scientific name given to the housefly, can be as deadly as we can imagine.

Our housefly starts life as a tiny egg, much smaller than a pinhead, deposited by a mature female in a pile of manure, or any rotting garbage. Within 24 hours, it hatches to a transparent, legless grub. Before a day is gone, its size has so tremendously grown that its inelastic skin cannot contain the body inside it. The skin burst open and releases the grub to crawl out and begins to grow a new skin. In three days, the process will repeat in as many times. On the fourth day, its transparent colour changes to a dull white. And it crawls out of its fourth skin and buries itself into the ground, just below the top soil.

For only three days during which the little fly is underground, it develops the pupal jacket, the striped body, the six legs, the two veined wings and the multi faceted eyes – a tremendous metamorphosis within such a short time. Then the pupa burst and out emerges the adult fly. Tunneling upward, it comes out into the sunlight ready to fly when its wings are dry and stiffened for its eight weeks of adult life.

From egg to adult takes less than 10 days. And this adult fly is ready immediately for breeding. If it is a female, in less than a week, it will lay its first batch of more than 100 eggs. This will be repeated at 10-day interval. In view of this speed of reproduction, it becomes apparent how huge the tribe would grow if unchecked. No wonder then that in a spate of a month after the first few flies are noticed within an area, it becomes a plague.

The adult housefly’s life is not a prettier spectacle than was in its infancy. Its prime concern is food. It relishes in equal enthusiasm decaying garbage or any filth it can get itself on. It flies from one kind of food to another – a disturbing fact in view of its highly specialised anatomy and physiology.

First, its body is covered in fine close growing hairs, which extends to the six legs. Second, its feet are covered with an extraordinary adhesive pad of sticky hairs. It is by this means that a fly can negotiate on smooth surfaces, even upside down on glass ceilings. And it is by the same means that it picks up and transmits myriad germs that cause diseases. Furthermore, the fly has no chewing mechanism. Accordingly, the fly has to soften anything it intends to eat, by regurgitating a drop of its last digested meal on the new food. It is this gruesome antic that the fly is performing at the dinner table when he seems to be exploring the sugar bowl, leaving behind what we refer to as “flyspecks”.

Steve Kinuthia is a veteran professional safari guide and the proprietor of Bushman Adventures Limited.





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