When do ticks settle on a host? - briefly
Ticks attach during the questing stage when they detect host cues such as heat, carbon‑dioxide and movement, usually within minutes to a few hours after contact. Engorgement starts once the mouthparts penetrate the skin and the tick secures its position.
When do ticks settle on a host? - in detail
Ticks attach to a host during the “questing” phase of their life cycle. After molting into the active stage—larva, nymph, or adult—each tick climbs vegetation and extends its forelegs to detect carbon dioxide, heat, and movement. The questing period begins when environmental conditions reach a threshold of temperature (generally above 7 °C) and relative humidity (above 70 %). Under these parameters, the tick’s metabolism is sufficient to sustain activity, and the risk of desiccation is minimized.
The timing of attachment is closely linked to host behavior:
- Diurnal activity – Many species are most active in the early morning and late afternoon, coinciding with the peak movement of mammals and birds.
- Seasonal patterns – In temperate zones, larvae and nymphs appear in spring, while adults are most abundant in late summer and early autumn. In subtropical regions, questing may continue year‑round if humidity remains high.
- Micro‑habitat selection – Ticks position themselves at heights matching the typical gait of their preferred hosts (e.g., 30–50 cm for small mammals, 1–1.5 m for larger ungulates).
Attachment occurs when a host brushes against the questing tick. The tick grasps the host’s hair or fur with its forelegs, inserts its chelicerae, and begins a slow blood meal. Feeding phases differ by stage:
- Larval attachment – lasts 2–4 days; the tick engorges on a small mammal or bird before dropping off to molt.
- Nymphal attachment – lasts 3–7 days; typically occurs on medium‑sized mammals, providing the primary window for pathogen transmission.
- Adult attachment – females feed for 5–10 days, acquiring a large blood volume necessary for egg production; males may remain attached for only a few hours while seeking mates.
Factors that accelerate or delay attachment include:
- Host density – higher densities increase encounter rates, shortening the questing interval.
- Vegetation structure – dense understory offers more questing sites, extending the period before successful attachment.
- Weather fluctuations – sudden drops in humidity or temperature force ticks to retreat to the leaf litter, pausing questing until conditions improve.
In summary, ticks commence host attachment when temperature and humidity support active questing, during periods when hosts are most likely to encounter vegetation at appropriate heights, and continue feeding for stage‑specific durations that enable development and reproduction.