What paralyzes a tick? - briefly
Acaricidal chemicals like permethrin, organophosphates, or carbamates cause paralysis by interfering with the tick’s nervous transmission. In laboratory settings, neurotoxic peptides derived from spider or scorpion venom can also immobilize ticks rapidly.
What paralyzes a tick? - in detail
Ticks become immobile when their nervous system is disrupted by chemicals, extreme temperatures, or dehydration. Synthetic acaricides act on neurotransmission. Permethrin and deltamethrin open sodium channels, causing uncontrolled firing and paralysis. Amitraz stimulates octopamine receptors, leading to loss of muscle coordination. Fipronil blocks GABA‑gated chloride channels, preventing inhibitory signals and resulting in spasms followed by collapse. Ivermectin binds glutamate‑gated chloride channels, producing hyperpolarization and flaccid paralysis. Organophosphates inhibit acetylcholinesterase, allowing acetylcholine accumulation and continuous stimulation of muscles until they cease function.
Environmental factors also induce immobilization. Exposure to temperatures below −10 °C or above 45 °C denatures proteins and disrupts ion gradients, halting movement. Prolonged desiccation removes hemolymph water, reducing turgor pressure and preventing leg extension. Physical compression, such as crushing or pinching, directly damages the cuticle and underlying musculature, leading to immediate loss of motility.
Biological agents contribute additional paralysis mechanisms. Entomopathogenic fungi (e.g., Metarhizium anisopliae) release proteases and secondary metabolites that degrade cuticular proteins and interfere with neural signaling. Nematodes of the genus Steinernema inject bacterial toxins that block neuromuscular transmission, rendering the tick immobile before death.
In summary, immobilization of ticks results from:
- Neurotoxic chemicals targeting sodium, GABA, octopamine, or glutamate receptors.
- Temperature extremes causing protein denaturation and ion imbalance.
- Severe dehydration leading to loss of internal pressure.
- Direct mechanical damage to the exoskeleton and musculature.
- Pathogenic fungi and nematodes producing neurotoxic substances.
Each method interferes with the tick’s ability to generate coordinated muscle contractions, producing a state of paralysis that precedes mortality.