What does a tick that hasn't fed look? - briefly
An unfed tick is a tiny, oval arachnid about 1–2 mm long, with a pale reddish‑brown or ivory exoskeleton and clearly defined segmentation. Its legs are long and slender, and the body lacks the swollen, balloon‑like shape observed after a blood meal.
What does a tick that hasn't fed look? - in detail
An unfed tick is a small arachnid, typically measuring 2–5 mm in length, depending on species. Its body consists of two distinct regions: the anterior capitulum, which houses the mouthparts, and the posterior idiosoma, which contains the legs and internal organs. The dorsal surface is generally smooth and light‑colored—ranging from pale brown to reddish‑orange—allowing it to blend with leaf litter and vegetation.
Key morphological features include:
- Four pairs of legs: each leg ends in a claw, enabling the tick to grasp hosts. Leg length exceeds body length, giving the animal a “spider‑like” appearance.
- Capitulum: a short, box‑shaped structure bearing chelicerae and a hypostome with backward‑pointing barbs. In the unfed state the hypostome is retracted, making the mouthparts appear compact.
- Scutum: a hard plate covering the dorsal shield of the male and, in many species, a portion of the female’s dorsum. The scutum is often darker than the surrounding cuticle, creating a contrasting pattern.
- Eyes: two simple eyes located near the anterior margin of the scutum; they are small and may be absent in some species.
- Sensory organs: Haller’s organs on the first pair of legs detect heat, carbon dioxide, and movement, facilitating host detection.
Sexual dimorphism is evident before feeding. Males retain a fully developed scutum that covers the entire dorsal surface, resulting in a flatter, more rigid appearance. Females possess a partial scutum, leaving much of the abdomen exposed; this area expands dramatically after engorgement, but in the unfed condition it remains a soft, flexible membrane.
Coloration varies among species. For example, Ixodes ricinus exhibits a reddish‑brown hue with a darker scutum, while Dermacentor variabilis appears darker overall with a lighter, patterned scutum. In all cases, the unfed tick lacks the swollen abdomen characteristic of a blood‑filled individual; the abdomen appears flat, with visible segmental plates and fine setae.
The combination of a compact capitulum, smooth dorsal shield, elongated legs, and modest size distinguishes a tick that has not yet taken a blood meal from its engorged counterpart.