How does a blood‑sucking tick look? - briefly
A blood‑feeding tick is a tiny, oval arachnid about 2–5 mm long when unfed, with a smooth, reddish‑brown body and four pairs of legs. After engorgement it expands to a soft, balloon‑like shape up to 10 mm or more, becoming pale gray.
How does a blood‑sucking tick look? - in detail
A blood‑feeding tick undergoes dramatic morphological changes as it fills with host blood. In its unfed state, the organism measures 2–5 mm in length, possesses a reddish‑brown dorsal shield (scutum) that covers the entire back in males and only the anterior portion in females, and displays a smooth, oval body shape. The ventral side bears the capitulum, a forward‑projecting structure that houses the hypostome, chelicerae, and palps; these components are adapted for piercing skin and anchoring to tissue.
During engorgement, the tick’s abdomen expands up to tenfold, reaching 10–12 mm in females and 6–8 mm in males. The cuticle stretches, becoming translucent and taking on a swollen, balloon‑like appearance. Color shifts from brown to a pale, bluish‑gray as the blood dilutes the original pigmentation. Legs remain proportionally short (four pairs, each ending in clawed tarsi) and retain mobility, allowing the tick to cling to the host’s hair or fur.
Key visual characteristics:
- Capitulum: elongated, visible from the ventral aspect; hypostome covered with backward‑pointing barbs.
- Scutum: hard, shield‑like plate; smooth surface, no distinct pattern.
- Eyes: absent in most species; sensory detection relies on Haller’s organ located on the first pair of legs.
- Legs: four pairs, each bearing sensory setae; movement limited but sufficient for attachment.
- Engorged abdomen: markedly distended, thin‑walled, semi‑transparent; surface may appear glossy due to blood pressure.
The transition from a flat, compact parasite to a bloated, soft‑bodied organism provides a reliable visual cue for identification and underscores the physiological adaptation that enables prolonged blood extraction.