Parasite Population Density Research Articles

The agencies in nature that influence population trends and levels of species are so numerous, and so interdependent and complex, that the only hope of understanding them appears to lie in studying the factors separately or in small related groups. The immediate objective is to reconstruct the effective environment by a sort of synthetic process, and the ultimate objective is to make it possible to evaluate the separate agencies by statistical analyses of field data. It is, of course, well known that population changes are associated with nutrition, with weather, with competition, with inherent changes in fecundity, and with the incidence of disease, parasites, and predators. The results of a considerable amount of research in these fields have been recorded. The writers will not undertake to discuss here these advances, as it would lengthen the paper unduly. Those interested in the causative agencies in population dynamics should refer to the various papers by: Thomas Park and associates on the effect of nutrition, and of competition, both interand intra-specific; Raymond Pearl, R. N. Chapman, V. Volterra, Janet Boyce, John Stanley, D. S. MacLagan, and A. C. Crombie on competition; F. S. Bodenheimer, James Davidson and associates, B. P. Uvarov, V. E. Shelford, L. C. Birch, and W. F. Cook on weather; and Paul Errington, G. F. Gause, A. J. Nicholson, W. R. Thompson, G. Salt, Marjory Walker, and Joyce Laing on

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