What happens to a tick that has become full of blood? - briefly
When a tick becomes engorged, it detaches from the host, digests the blood, and then proceeds to lay eggs before eventually dying.
What happens to a tick that has become full of blood? - in detail
When a tick completes a blood meal, its abdomen expands dramatically, increasing volume up to 100 times the unfed size. The cuticle, a flexible exoskeleton, stretches to accommodate the influx, while internal muscles relax to prevent rupture. Blood is stored in the midgut lumen, where digestive enzymes break down proteins, hemoglobin, and lipids. The tick’s metabolic rate rises sharply, converting nutrients into energy for reproduction and development.
During this phase, the salivary glands continue to secrete anti‑coagulants and immunomodulatory compounds into the host, facilitating prolonged feeding and enhancing pathogen transmission. Pathogens acquired from the host, such as Borrelia, Rickettsia, or viruses, migrate from the midgut to the salivary ducts, positioning them for injection into subsequent hosts.
Key physiological processes include:
- Hemolymph dilution: Blood mixes with the tick’s own fluid, reducing osmotic stress.
- Hormonal regulation: Ecdysteroids trigger the cessation of feeding and initiate the detachment reflex.
- Excretion: Excess water and waste are expelled through Malpighian tubules, concentrating nutrients for storage.
- Reproductive activation: In females, engorgement stimulates ovarian development; eggs mature within days.
After the engorged state, the tick drops off the host, often seeking a protected environment. It then undergoes a rapid molt (larva → nymph, nymph → adult) or, for adult females, proceeds to oviposition, laying thousands of eggs in the surrounding substrate. The engorged tick’s lifespan ends shortly after egg laying, as the energy reserves are exhausted.