Experimental studies in insect parasitism. I.—Introduction and technique

Abstract

It is a matter of common knowledge that the numbers of most animals are partially regulated by carnivorous and parasitic species that prey upon them. But, although the simple fact is well known, and although the amount of regulation exercised by the parasitic animals has in some oases been measured, the precise nature of that regulation—the numerical interaction that goes on generation after generation between the parasite and its host—is still very imperfectly understood. The reason is not hard to find. Experimental data that might serve as a basis for that understanding are almost entirely lacking. In their absence, mathematical consideration of the subject by Volterra, Thompson, Bailey, and others, has necessarily been based upon field observation. But such information is not amenable to the strict analysis that the problem requires: it is the result of unknown environmental conditions; its quantities are samples; it deals with only one or two successive generations. Consideration, no matter how inspired, of such data can result only in conjecture. The solution of a problem so essentially dynamic must be supported by experimental evidence.