Tick larva — what does it look like? - briefly
A tick larva is a minute, translucent or pale oval measuring roughly 0.2–0.4 mm and bearing six short legs. It lacks the enlarged, darkened body of nymphs and adults, making it easily missed on hosts.
Tick larva — what does it look like? - in detail
Tick larvae are the earliest free‑living stage of ixodid and argasid ticks. They emerge from eggs as microscopic, six‑legged organisms that can be seen only with magnification. Typical dimensions range from 0.1 mm to 0.5 mm in length, depending on species and whether the larva is unfed or partially engorged.
The body consists of a smooth, rounded capitulum and a compact idiosoma. The dorsal surface is usually translucent to pale amber, allowing internal organs to be faintly visible. Ventral coloration may be slightly darker, often matching the substrate on which the larva rests.
Key morphological features include:
- Six legs: three pairs attached near the posterior margin of the idiosoma; each leg ends in a small claw for grasping host hair.
- Capitulum: equipped with chelicerae and a short hypostome; the mouthparts are not yet visible from the dorsal view.
- Eyes: absent in most larval species, relying on sensory organs in the palps for host detection.
- Scutum (if present): a narrow, lightly pigmented shield covering part of the dorsal surface; in some genera the scutum is absent.
- Spiracular plates: tiny openings on the ventral side for respiration, often indistinct without magnification.
When a larva feeds, its abdomen expands dramatically, turning from translucent to a darker, blood‑filled appearance. Engorged larvae can increase their volume tenfold, reaching up to 1 mm in length. After feeding, the larva detaches, drops to the ground, and molts into a eight‑legged nymph.
Differentiation from nymphs and adults relies primarily on leg count, size, and the proportion of the scutum to the body. Nymphs possess eight legs and a larger scutum, while adults have more robust mouthparts and distinct genital openings.