Physiological traits of invertebrates entering cryptobiosis in a post-embryonic stage

Cryptobiosis is the state when the metabolic activity of an organism is hardly measurable or is reversibly at a standstill. Many groups of invertebrates have this ability, and can be divided into two types according to the developmental stage in which it occurs; embryonic (eggs) or post-embryonic stages (larvae and adults). The latter must be able to reversibly regulate the physiology and biochemistry of development and cryptobiosis. There are several reviews on cryptobiosis and its regulation, but none on the physiological mechanism of cryptobiosis in chironomids. The present paper reviews the physiological traits of invertebrates entering cryptobiosis in a post-embryonic stage. These unique phenomena, which occur in a post-embryonic stage of three groups of cryptobiotic invertebrates (insects, tardigrades and nematodes) are discussed with particular reference to; 1) the behavioural and physiological adaptations of cryptobiotic invertebrates, 2) role of trehalose in cryptobiosis and 3) regulation of cryptobiosis.