How do fleas bite? - briefly
Fleas penetrate the skin with razor‑thin stylet mouthparts, inject saliva containing anticoagulant and anesthetic compounds, and draw blood through the same canal. The puncture typically produces a small, itchy papule.
How do fleas bite? - in detail
Fleas obtain blood through a specialized feeding apparatus that penetrates the host’s skin. The mouthparts consist of a hardened, needle‑like structure called the proboscis, which houses a pair of slender stylets. When a flea lands on a suitable mammal or bird, it searches for a thin area of skin, often near hair follicles, using sensory receptors that detect heat and carbon‑dioxide.
The feeding sequence proceeds as follows:
• The flea positions its body so that the proboscis can be driven downward.
• Muscular contraction forces the stylets through the epidermis and into the dermal capillary network.
• One stylet functions as a hollow canal that draws blood, while the second injects saliva containing anticoagulant compounds such as apyrase and anticoagulant peptides.
• Saliva prevents clot formation and numbs the immediate area, allowing continuous flow of blood.
• The flea ingests the fluid, which is stored in its distensible abdomen; a single blood meal can increase body weight by up to 50 %.
During this process, the flea’s rapid, repetitive movements create a characteristic “twitch” that may be felt as a small, painless bite. The host’s immune response often produces a localized inflammatory reaction, resulting in itching and a raised welt. Repeated feeding can transmit pathogens such as Yersinia pestis or Bartonella henselae, underscoring the medical significance of the flea’s biting mechanism.