What is a tick made of? - briefly
A tick is built from a hard chitin exoskeleton that houses its internal organs, muscles, and nervous system. Its mouthparts contain salivary glands that secrete anticoagulant and immunomodulatory proteins.
What is a tick made of? - in detail
Ticks are arthropods belonging to the subclass Acari. Their bodies consist of two primary regions: the anterior capitulum (mouthparts) and the posterior idiosoma (the main body). The outer covering of the idiosoma is a hard exoskeleton composed mainly of chitin, a polysaccharide reinforced with proteins and sclerotized cuticular proteins that provide rigidity and resistance to desiccation.
Beneath the cuticle lies a thin epidermal layer that secretes the cuticular material and houses sensory sensilla. The internal cavity, or hemocoel, is filled with hemolymph—a fluid containing water, ions, sugars, lipids, and hemocytes that perform immune functions. Muscle fibers are attached to the internal surface of the cuticle, enabling movement of the legs and feeding apparatus.
The capitulum contains specialized structures:
- Chelate chelicerae for cutting skin.
- A hypostome equipped with barbs for anchoring during blood meals.
- Palps that detect host cues.
Salivary glands, located within the idiosoma, produce a complex mixture of proteins, anticoagulants, and enzymes that facilitate blood ingestion and modulate host defenses. The gut epithelium lines the midgut, where ingested blood is stored and digested; it contains digestive enzymes such as proteases and lipases.
Reproductive organs include paired ovaries in females and testes in males, surrounded by accessory glands that secrete substances for egg development or sperm transfer. In engorged females, the abdomen expands dramatically, accommodating a mass of blood that can constitute up to 100 % of the tick’s body weight.
In summary, a tick’s composition integrates:
- Chitinous exoskeleton with sclerotized proteins.
- Epidermal and muscular layers.
- Hemolymph with cellular and soluble components.
- Specialized mouthparts and sensory organs.
- Salivary and digestive glands.
- Reproductive structures.
These elements collectively enable attachment, blood feeding, digestion, and reproduction.