How are chewing lice different from sucking lice?

Chewing lice and sucking lice are both wingless, parasitic insects belonging to the order Phthiraptera, but they differ significantly in their mouthparts, feeding habits, and host interactions.12

Mouthparts and Feeding

• Chewing Lice (suborders Amblycera and Ischnocera): These insects possess mandibulate (chewing) mouthparts. They feed primarily on skin debris, secretions, feathers, and occasionally tissue fluids or blood. They are not considered bloodsuckers, though they can cause significant discomfort to their hosts.213
• Sucking Lice (suborder Anoplura): These lice have specialized piercing mouthparts consisting of three fine, eversible stylets. They feed exclusively on blood, injecting saliva to prevent coagulation while they feed. They also feature a strong pump associated with the esophagus to assist in sucking blood.243

Physical and Biological Differences

• Anatomy: Sucking lice have all three thoracic segments fused into a single unit and possess a single claw on their legs, which acts as a hair-clasping organ. Chewing lice exhibit more varied thoracic structures and typically have two claws when inhabiting birds.4
• Host Range: Chewing lice parasitize both birds and mammals, but they are not human parasites. Sucking lice are found on mammals, including humans.12