pedipalp

Pedipalp is the second pair of appendages located near the mouth in chelicerates, a group that includes spiders, scorpions, pseudoscorpions, harvestmen, and mites. They are typically leg-like but are often specialized for feeding, sensation, prey capture, or reproduction. The pedipalps arise from the prosoma and usually have multiple segments, ending in a sensory or grasping distal segment. Their form and function vary widely among groups, reflecting different ecological roles.

In spiders, pedipalps resemble small legs and serve multiple roles. In males, the distal part of the pedipalp is highly modified into a reproductive organ—featuring a palpal bulb and often an embolus—that stores and transfers sperm to the female during mating. In both sexes, pedipalps can assist with sensory perception, prey handling, and courtship behaviors, and they frequently contribute to species-specific identification in taxonomy.

In scorpions, pedipalps are the large pincers or chelae, used for grasping, securing, and crushing prey, as well as for defense. The structure and strength of the pedipalps vary markedly among species and can influence prey choice and combat performance.

Other chelicerates, including pseudoscorpions, harvestmen, and many mites, also possess pedipalps that function in feeding, manipulation of objects, and sensory perception. Across these groups, pedipalps represent a key site of morphological diversity and play a fundamental role in feeding ecology, reproduction, and interaction with the environment.