How do ticks look? - briefly
Ticks are tiny, oval arachnids, usually 2–5 mm long when unfed, with a reddish‑brown, flattened body and eight legs. After feeding, females swell to roughly 10 mm, becoming a soft, balloon‑shaped form.
How do ticks look? - in detail
Ticks are small arachnids ranging from 2 mm to 10 mm in length when unfed. Their bodies consist of two main sections: the anterior capitulum, which houses the mouthparts, and the posterior idiosoma, which contains the legs and internal organs. The capitulum projects forward and appears as a beak‑like structure, often darkened by blood pigments after feeding.
Unengorged specimens exhibit a flattened, oval shape with a hard, chitinous exoskeleton. Colors vary among species and life stages, typically including shades of brown, reddish‑brown, gray, or black. Some species display distinct patterns, such as mottled or striped markings on the dorsal surface.
When a tick feeds, its abdomen expands dramatically, becoming spherical or balloon‑like. Engorged females can increase their body mass by up to 100 times, reaching lengths of 15 mm or more. The cuticle stretches, and the color may shift to a deep reddish hue due to the ingested blood.
Key morphological features include:
- Eight legs on the nymphal and adult stages; larvae possess six legs.
- Haller’s organ on the first pair of legs, a sensory structure used to detect hosts.
- Scutum (in hard ticks) – a rigid shield covering part of the dorsal surface; soft ticks lack this feature.
- Mouthparts – chelicerae for cutting skin and a barbed hypostome for anchoring during blood intake.
Life‑stage variations affect appearance:
- Egg – microscopic, oval, no legs.
- Larva – six-legged, translucent or light brown, approximately 0.5 mm.
- Nymph – eight-legged, darker, 1–2 mm, similar shape to adults but smaller.
- Adult – fully developed legs, distinct sexual dimorphism; females larger, especially after engorgement, while males remain relatively small and do not engorge.
Species differences influence size and coloration. For example, the American dog tick (Dermacentor variabilis) is typically reddish‑brown with white markings, whereas the deer tick (Ixodes scapularis) is smaller, dark brown, and lacks prominent dorsal patterns.
Overall, ticks present a compact, armored profile when unfed, transforming into a markedly enlarged, blood‑filled body after attachment, with species‑specific coloration and structural traits that aid identification.