Abstract: For most species, diapause is a developmental option and individuals have the capacity to determine whether or not they enter that state by monitoring changes in environmental and internal conditions through the mediation of endocrinological mechanisms. Diapause intervenes in all the major stages of the life cycle, and the egg stage is one of the most suitable stages for diapause. This paper is a review on insect diapause，with special emphasis on egg diapause in the following areas of research: individual ecology, environmental physiology, endocrinology, biochemistry and molecular biology.

Key words: insect, diapause, embryonic stage