How does a tick breathe when it attaches? - briefly
While attached, a tick respires through ventral spiracular openings that stay exposed to the air. These spiracles provide the only pathway for oxygen intake and carbon‑dioxide release during feeding.
How does a tick breathe when it attaches? - in detail
Ticks remain attached to a host for several days while they ingest blood. During this period they rely on a tracheal system rather than lungs. Air enters through a pair of spiracles located on the ventral surface of the idiosoma. The spiracles open into a network of fine tubes (tracheae) that branch throughout the body, delivering oxygen directly to tissues.
When the tick inserts its hypostome into the skin, the spiracles stay exposed to the external environment. The tick does not seal its respiratory openings; instead, it continues to draw air through the spiracles by passive diffusion and, to a limited extent, by muscular contractions of the body wall that create slight pressure changes.
Key aspects of the respiratory process during feeding:
- Spiracle placement: ventral position ensures access to air even when the tick is anchored to the host’s skin.
- Tracheal architecture: a rigid, non‑collapsible network permits oxygen transport without the need for a circulatory carrier.
- Diffusion-driven flow: concentration gradients between external air and internal tissues drive gas exchange; the tick’s low metabolic rate reduces the demand for active ventilation.
- Limited muscular assistance: occasional contractions of the abdomen aid in moving air when diffusion alone is insufficient, especially during prolonged attachment.
The tick’s cuticle is impermeable to water, preventing desiccation while the spiracles remain open. Waste gases, mainly carbon dioxide, exit the same spiracular openings, maintaining a steady exchange. Because the feeding period can extend up to a week, the tracheal system remains functional throughout, allowing the parasite to sustain its metabolic needs until detachment.