Recent Advances in Entomology

Abstract

The avoidance of disease-carrying insects and their effective destruction or control by the most economical means demands an intimate knowledge of their life-history or, as it is usually called to-day, their ecology. Important aspects of ecology with which the medical entomologist is constantly faced concern the effects of climate, of temperature, moisture and drought, or the effects of nutrition, upon the prevalence of insects as determined by their rates of multiplication and power of survival. Much can be learned from an empirical study in the laboratory of the effects of the various ecological factors upon individual insects or populations of insects; particularly if such a study is checked and compared at every stage by observations in the field. That is the technique which at the present time is leading to a far better understanding of many groups of insects, notably the tsetse-flies and the plague-carrying fleas. But when the analysis is pressed further, these ecological factors can exert their effects on the insect populations only by their influence upon the physiology of individual insects. So that for the proper understanding of ecology we need a thorough knowledge of insect physiology. Indeed, were the physiology of a given species sufficiently well known, many of its ecological responses to the environment could be predicted. And as ecology is based on physiology, so of course is physiology based on morphology. These inter-relations between medicine and agriculture on the one hand and academic entomology on the other are well illustrated in Imms' " Recent Advances in Entomology, " the second edition of which has just been published. This edition is larger than its predecessor by 56 pages; but it deals with the same range of subjects: morphology, metamorphosis, palaeontology, sense organs and behaviour, coloration, many aspects of ecology and their practical application, parasitism and biological control. On the applied side, most of the examples are from agriculture. There is an account of the biological races of mosquitoes, which is perhaps not better than can be readily found elsewhere; but it is of undoubted value to the medical entomologist to see this problem related to the question of biological races in general. V. B. Wigglesworth.