What do fleas look like and how do they bite? - briefly
Fleas are tiny, dark brown, wing‑less insects about 1–3 mm long and laterally flattened for jumping. They bite by using needle‑like mouthparts to pierce the host’s skin and inject saliva that provokes irritation.
What do fleas look like and how do they bite? - in detail
Fleas are small, laterally flattened insects measuring 1–4 mm in length. Their bodies are covered with tiny, backward‑pointing spines that facilitate movement through host fur. The exoskeleton is dark‑brown to reddish‑black, sometimes with a lighter abdomen. Six legs end in strong, hook‑shaped tarsal claws that grip hair shafts. Compound eyes are reduced, and antennae are short, concealed beneath the head capsule. Their wings are absent; locomotion relies on jumping, powered by a resilient protein called resilin stored in the hind‑leg femur, allowing leaps up to 150 times body length.
Biting involves a specialized mouthpart called the proboscis, a needle‑like structure formed from elongated mandibles and maxillae. The process proceeds as follows:
- Detection – sensory receptors on the flea’s antennae sense heat, carbon dioxide, and movement of a potential host.
- Attachment – the flea lands on the host’s skin or fur and secures itself with its claws.
- Penetration – the proboscis pierces the epidermis, guided by saliva that contains anticoagulants and anesthetic compounds.
- Blood ingestion – a muscular pump draws blood up the proboscis into the flea’s gut.
- Detachment – after feeding, the flea releases its grip and may move to another site.
Saliva components prevent clotting and dull the host’s pain response, enabling the flea to feed for several minutes without detection. Repeated bites produce small, red, itchy papules that may develop into pustules if secondary infection occurs. The combination of compact morphology, powerful jumping ability, and efficient piercing apparatus makes fleas highly effective ectoparasites.