African Nature Notes and Reminiscences

by Frederick Courteney Selous

CHAPTER IX

NOTES ON THE TSE-TSE FLY

Connection between buffaloes and tse-tse flies—Sir Alfred Sharpe's views—Buffaloes and tse-tse flies both once abundant in the valley of the Limpopo and many other districts south of the Zambesi, in which both have now become extinct—Permanence of all kinds of game other than buffaloes in districts from which the tse-tse fly has disappeared—Experience of Mr. Percy Reid—Sudden increase of tse-tse flies between Leshuma and Kazungula during 1888—Disappearance of the tse-tse fly from the country to the north of lake N'gami after the extermination of the buffalo—History of the country between the Gwai and Daka rivers—And of the country between the Chobi and the Zambesi—Climatic and other conditions necessary to the existence of the tse-tse fly—Never found at a high altitude above the sea—Nor on open plains or in large reed beds—"Fly" areas usually but not always well defined—Tse-tse flies most numerous in hot weather—Bite of the tse-tse fly fatal to all domestic animals, except native goats and perhaps pigs—Donkeys more resistant to tse-tse fly poison than horses or cattle—Tse-tse flies active on warm nights—Effect of tse-tse fly bites on human beings.

As it is impossible for any one who had much experience with buffaloes in the interior of South Africa in the days when these animals were excessively plentiful not to have a very lively remembrance also of the tse-tse flies by which they were almost invariably accompanied, I think a few words concerning these insects will not be out of place. My remarks must, however, be understood to apply not to all tse-tse flies—for there are several distinct species of the genus inhabiting different parts of Africa—but to Glossina morsitans alone, which, so far as I am aware, is the only species of tse-tse fly as yet known to occur in Africa to the south of the Zambesi river.

In the countries farther north, men of great experience have expressed the opinion that there is no connection between tse-tse flies and buffaloes or any other kind of wild animals. Writing on this subject, Sir Alfred Sharpe has recently stated, in the course of an article published in the Field newspaper for November 2, 1907:

So far as Africa north of the Zambesi is concerned (i.e. British Central Africa, North-Eastern Rhodesia, Portuguese East Africa, the south-west portion of German East Africa, and the south-east corner of the Congo State), I am able to speak with some experience, having spent twenty years in those regions. The results of the last few years' careful observation have led me to a decided opinion that the existence of tse-tse is not dependent on wild game of any description. Tse-tse (mostly Glossina morsitans in British Central Africa), when it has the opportunity, sucks the blood of all such animals as it can get at in tracts of country in which it exists, but I think that blood is an exceptional diet (as in the case of the mosquito).

The great experience which Sir Alfred Sharpe has enjoyed in British Central Africa—which territory he has so ably administered for many years—entitles any views he may express on any subject concerning that country to the very greatest respect; but it must, nevertheless, be said that the conclusions he has arrived at concerning the requirements and life-history of the tse-tse fly (of the species Glossina morsitans), in the countries lying to the north of the Zambesi river, in which his observations have been made, are diametrically opposed to the teachings of history throughout the whole of Africa to the south of the Zambesi, where not only would it seem that these insects live entirely upon mammalian blood, but that they have become so highly specialised that they can only maintain their vitality on the blood of buffaloes; for it can be shown that wherever tse-tse flies were first encountered by the earliest European travellers in South Africa, there also buffaloes were either constantly present or visited such districts during certain months of every year; and that as soon as the buffaloes were either exterminated or driven out of any such territories, a remarkable diminution in the numbers of the tse-tse flies was at once observed; whilst in a very few years after the complete extinction of the buffaloes these insects entirely ceased to exist, even though other kinds of game remained in the country for years afterwards. A few facts bearing on this subject, which, being historical, can neither be questioned nor, I think, explained away as coincidences, are well worth enumerating.

In 1845 Mr. William Cotton Oswell—the well-known traveller and hunter—encountered tse-tse fly on the Maghaliquain river, a tributary of the Limpopo running through the Northern Transvaal, and it is an historical fact that at that time the whole of the Northern Transvaal lying between the Waterberg and Zoutpansberg ranges and the Limpopo, as well as a large area of country lying to the north of that river, was the haunt of great herds of buffaloes, and that the banks of every river draining this large territory, as well as many tracts of forest lying between these rivers, were at the same time infested with tse-tse flies.

In 1871 the well-known traveller Mr. Thomas Baines, as he has recorded in his book The Gold Regions of South-East Africa, still found the tse-tse fly numerous on the Maghaliquain river, as well as in the neighbourhood of the Macloutsie and Shashi rivers, and in many other places throughout the valley of the Limpopo.