Abstract: Differences in body shape and size, as well as differences in body coloration between male and female of same species are called as sexual dimorphism (SD). Sexual difference in body size or in other words, sexual size dimorphism (SSD), attracts a lot of attention of researchers. SSD is a common phenomenon for animals, which reflects the different adaptation of male and female under the selection pressure of the environment. There are three main hypotheses for the causes of SSD, i.e., sexual selection pressure, fecundity selection pressure, and ecological niche divergence. SSD is a very common phenomenon for amphibians and reptiles. Due to the lifelong growth, the individual sexual size dimorphism of amphibians and reptiles is the result of the comprehensive effects of various factors. Therefore, amphibians and reptiles are the ideal models for studying the evolution of sexual dimorphism, being researched widely and deeply. This paper reviewed the research progress on the SSD of amphibians and reptiles, with the focuses on the definitions, patterns, and evolution mechanisms of SSD. Aiming at the present status and existing problems in our related researches, some suggestions for the further research of the SSD of amphibians and reptiles were proposed.

Key words: multi-pesticide resistance, ecological equilibrium., pesticide, target enzyme