关键词: 昆虫, 体型, 性体型二型性, 环境因素, 地理变异

Abstract: Body size, a fundamental morphological trait in insects, affects virtually all physiological and life-history traits of an insect. Body size always shows a significant gradient change among different geographic populations of the same insect species. Many environmental factors including temperature, humidity, photoperiod, host plant, and population density contribute to this gradient change and also affect insect body size within a population. Males and females differ in their body size, a phenomenon called sexual size dimorphism (SSD). There is also geographical variation in SSD. The ways those differences formed have been comprehensively analyzed, and the formation mechanisms of these variations caused the formulation of many hypotheses, which had been proved in many insect species. In this article, we summarized the ways insect body size varies among different geographic populations, the environmental factors affecting insect body size among different geographic populations and within one population, the phenomenon of sexual size dimorphism and the geographic variation of sexual size dimorphism, the ways sexual size dimorphism forms, the ultimate cause of sexual size dimorphism, the environmental factors of geographic variation of sexual size dimorphism from the three levels of interpopulation, intrapopulation and individuals of different sex. Suggestions for future related research were also given.

Key words:  Insect, body size, sexual size dimorphism, environmental factors, geographic variation