How can you distinguish a flea from a louse? - briefly
Fleas are laterally flattened, possess powerful hind legs for jumping, and feed on mammalian blood, whereas lice are dorsoventrally flattened, crawl with short clawed legs, and are host‑specific parasites of birds or mammals. Their leg morphology and locomotion style provide the most reliable visual distinction.
How can you distinguish a flea from a louse? - in detail
To differentiate a flea from a louse, examine morphology, behavior, habitat, and life‑cycle traits.
Fleas
- Size: 1.5–3.5 mm, laterally compressed body.
- Body shape: streamlined, hardened exoskeleton; hind legs enlarged for powerful jumps.
- Locomotion: can leap up to 150 times body length; rarely crawl.
- Antennae: short, concealed in grooves.
- Mouthparts: siphoning stylet for piercing skin and sucking blood.
- Color: dark brown to reddish.
- Life cycle: eggs, larvae, pupae, adult; larvae develop in the host’s environment (e.g., bedding, soil).
- Host range: many species infest mammals and birds; not strictly host‑specific.
Lice
- Size: 1–4 mm, dorsoventrally flattened body.
- Body shape: flat, adapted to cling to hair or feathers; legs positioned forward for grasping.
- Locomotion: crawl continuously; no jumping ability.
- Antennae: long, visible, segmented.
- Mouthparts: either chewing (chewing lice) or piercing‑sucking (sucking lice) for feeding on skin debris or blood.
- Color: grayish, pale brown, often matching host hair.
- Life cycle: egg (nit) attached to hair shafts, nymphal molts on host, adult remains on host; entire development occurs on the host.
- Host specificity: each species usually limited to a single host species or closely related group.
Key diagnostic points
- Body compression: lateral (flea) vs. dorsal (louse).
- Leg adaptation: enlarged hind legs for jumping (flea) vs. forward‑oriented legs for crawling (louse).
- Development environment: off‑host pupation (flea) vs. on‑host egg attachment (louse).
- Host specificity: broad (flea) vs. narrow (louse).
These criteria allow reliable identification of the two ectoparasites.