干旱区生态环境知识资源中心

Ecdysis in scorpions has some common features in all species in which it has been examined. Immature scorpions about to molt become less active, and the cuticle changes in appearance. When humidity and other conditions are suitable, the animal begins ecdysis with cheliceral and pedipalpal movements and internal processes that tear the pleural membrane just ventral to the anterior and lateral edges of the carapace. The carapace is pushed upward from within, and the animal starts to emerge through the opening made by the elevated carapace. This is usually done in the prone position. As the anterior body emerges, the pedipalps and walking legs are stretched posteriorly with their distal ends temporarily confined within the old exoskeleton. The buthid scorpions Androctonus australis and Parabuthus transvaalicus become supine before they begin to emerge. Ecdysis is completed lying supine, and the animal rights itself shortly thereafter. A turnover from upright to supine is not seen at any other time in scorpions. After prone or supine extraction, the exuvium includes the cuticle of booklungs, bristles, and sensilla and is relatively intact except for the wedge-shaped opening at the anterior end.