How can you tell that fleas are dead? - briefly
A dead flea stays motionless despite gentle prodding, heat, or carbon‑dioxide exposure. Its body appears limp and often darkens in color.
How can you tell that fleas are dead? - in detail
Fleas that are no longer alive exhibit distinct, observable characteristics. Visual inspection is the quickest method. A dead specimen appears limp, with the abdomen flattened and the legs curled inward instead of extending outward. The body loses its glossy sheen and may become dull or slightly desiccated.
Absence of movement confirms mortality. Gently tapping the surface where the flea resides should produce no reaction; live fleas will attempt to jump or crawl away. Applying a fine brush or a gentle puff of air will elicit a rapid escape response from a living flea, while a deceased one remains motionless.
Respiratory cues are also reliable. Living fleas display tiny, rhythmic abdominal movements that indicate breathing. Under magnification, the presence of clear, unobstructed spiracles—small openings used for gas exchange—suggests vitality; blockage or collapse of these structures typically accompanies death.
Temperature testing can provide additional evidence. A living flea maintains a temperature slightly above ambient due to metabolic activity. Using an infrared thermometer or a touch-sensitive probe will reveal a cooler temperature in a dead insect.
Chemical stimulation offers another verification step. A drop of ethanol or a small amount of CO₂ will cause a live flea to become active. Lack of response after exposure indicates that the flea is no longer viable.
In summary, to determine that a flea is dead, observe for:
- Limp, flattened body and curled legs
- No movement when disturbed (tapping, brushing, air puff)
- Absence of abdominal respiration
- Reduced body temperature relative to surroundings
- No reaction to chemical stimulants (ethanol, CO₂)
These criteria, applied individually or in combination, provide a definitive assessment of flea mortality.