The South African Bont tick is a hard tick that transmits diseases to livestock (ruminants). During feeding, the tick has a rapid growth phase in which the cuticle expands to create a 10 fold larger volume. How does it do that?
The Bont tick is capable of generating some of the highest pressures measured for any animal. During expansion, the cuticle thins by half and is permanently deformed by about 40%. Like all arthropods, ticks have an exoskeleton made from protein and reinforced by strands of the polysaccharide chitin. The cuticle structure is resistant to tearing and deformation. Cuticle in which the proteins and chitin are not cross linked is more pliable and can expand. Some expansion is common in blood feeding insects as well as ticks. Hydraulic pressure may have a role in these expansions but the pressure is not as great.