"Motion" - what is it, definition of the term
«Motion» denotes the alteration of an object’s position as time progresses, quantified by displacement, velocity, and acceleration; it includes linear, rotational, and oscillatory forms and is governed by classical mechanics and, where relevant, relativistic theory, observable from the locomotion of a tick to the trajectory of a particle.
Detailed information
Ticks rely on a passive locomotion strategy. After hatching, the larva climbs vegetation and awaits a host. Contact with a suitable animal triggers a rapid forward thrust that lifts the organism onto the host’s skin. The forward motion lasts a fraction of a second, after which the tick secures itself with its mouthparts.
Bugs exhibit active locomotion driven by coordinated leg movements. Six legs generate alternating strides, allowing precise navigation across plant surfaces. Sensory hairs detect vibrations, prompting adjustments in direction and speed. Typical walking speed ranges from 0.5 mm s⁻¹ to 1 mm s⁻¹, while short bursts can reach up to 5 mm s⁻¹.
Lice perform continuous crawling along hair shafts. Their clawed tarsi grip individual fibers, enabling forward progression without slipping. The organism advances by alternating leg pairs, producing a smooth wave-like motion. Average displacement measures 0.2 mm s⁻¹, sufficient to maintain proximity to the host’s scalp.
Fleas achieve rapid jumping locomotion. Powerful hind‑leg muscles store elastic energy in a protein matrix, releasing it to propel the insect upward and forward. Jump distances exceed 100 mm, while horizontal speeds approach 1 m s⁻¹. After landing, fleas resume walking using six legs to locate a host’s fur.
Key characteristics of locomotion across these ectoparasites:
- Passive attachment (ticks) versus active crawling (bugs, lice) versus jumping (fleas)
- Leg count and specialization: six walking legs for bugs and lice; four functional legs for fleas (hind legs repurposed for jumps)
- Speed range: millimetres per second for crawlers, metres per second for jumpers
- Sensory triggers: temperature, carbon‑dioxide, vibration, and host movement
Understanding these mechanisms informs control strategies and predicts infestation patterns. «Effective management requires targeting the specific locomotion mode of each parasite».