Why does a flea jump on the bed? - briefly
Fleas jump on a mattress to locate a warm blood‑feeding host and to avoid being crushed by movement. Heat, carbon dioxide and the soft fabric trigger their powerful hind‑leg thrust.
Why does a flea jump on the bed? - in detail
Fleas possess a specialized protein called resilin in their hind‑leg pads. This elastic material stores energy when the pads are compressed and releases it in a fraction of a millisecond, generating acceleration up to 100 g. The rapid release propels the insect upward and forward, allowing it to clear distances many times its body length.
Several stimuli trigger the leap onto a sleeping surface:
- Heat from a human or animal body raises the flea’s metabolic rate.
- Carbon dioxide exhaled by the host signals proximity.
- Vibrations caused by movement in the bed sheet stimulate the flea’s mechanoreceptors.
- Moisture retained in bedding maintains the flea’s hydration and enhances grip.
A mattress provides an optimal landing zone. The fabric and padding retain warmth, creating a microclimate that matches the flea’s preferred temperature range (≈30 °C). The close contact with a host supplies a continuous source of blood meals, while the soft surface reduces the risk of injury upon impact.
The physics of the jump can be summarized:
- Energy stored in resilin ≈ 0.5 µJ.
- Force generated ≈ 10 µN.
- Acceleration ≈ 100 g.
- Jump height ≈ 15 mm; horizontal distance ≈ 20 mm.
These parameters enable the flea to bridge the gap between the floor and a bed, even when the host is covered by blankets.
Effective control focuses on disrupting the flea’s life cycle: regular washing of bedding at ≥ 60 °C, vacuuming to remove eggs and larvae, and treating pets with approved ectoparasitic agents. By eliminating the environmental cues that stimulate jumping, the likelihood of fleas reaching the sleeping area is markedly reduced.