1.3 Larval Source Management

The interest in mosquito populations originated from an academic discussion, in 1904, that critiqued a larval source management program in Mian Mar. One fact that clearly irked Ross was the lack of any good method for measuring mosquito populations accurately. The problem at hand:

Suppose that we have to deal with a country of indefinite extent, every point of which is equally favorable to the propagation of gnats (or of any other animal); and suppose that every point of it is equally attractive to them as regards food supply; and that there is nothing, such for instance as steady winds or local enemies, which tends to drive them into certain parts of the country.- Then the density of the gnat population will be uniform all over the country. Of course, such a state of things does not actually exist in nature; but we shall nevertheless find it useful to’ consider it as if it does exist, and shall afterwards easily determine the variations from this ideal condition due to definite causes. Let us next select a circumscribed area within this country, and suppose that operations against the insects are undertaken inside it, but not outside it. The question before us is the following: How far will these operations affect the mosquito density within the area and immediately around it?

Ross’s question was:

How large must that radius be in order to render the center entirely mosquito-free?