Organisms often suffer from water stress or dehydration under drought, high salt or freezing conditions. They have evolved various physiological and biochemical mechanisms to survive these water stresses. The most unique and ultimate strategy against drought stress is cryptobiosis, which is the state of an organism that can tolerate extremely desiccation without ill effects and survive for an extended period. An African chironomid, Polypedilum vanderplanki, is the highest and largest multicellular animal with cryptobiotic ability. The cryptobiotic larva can tolerate not only exposure to extremely high (106℃) and low (-270℃) temperatures but also soak into pure ethanol. We found that this chironomid accumulated a large amount of trehalose (ca. 20% of the dry body weight) at the state of cryptobiosis, and cerebral regulation was not involved in the process for induction of cryptobiosis.
