Question

What are the specializations that fleas have developed as ectoparasites?

Answer 1

Fleas are ectoparasites which move by hopping and jumping. They do not carry disease-causing agents; they are, instead, the direct cause of disease.These ectoparisites have undergone morphological specialisations for life on the host by developing specific means of attachment to the host.

Small and wingless, fleas are parasites that survive by ingesting the blood of warm-blooded hosts like cats, dogs, and humans. A flea’s entire body is designed to maximize eater—the head is surrounded by sharp spikes, and mouths are adept at piercing through a host’s skin and sucking out blood. The lateral flattening of fleas is a morphological adaptation to life in the covering layers of the host. Flattening also allows them considerable freedom of movement though the hair or feathers and helps the flea evade the host's grooming activities.

Some permanent ectoparasits effect an even stronger attachment to the host. One such specialisation are the tarsal claws used for gripping the hair or feathers of the host. The sticktight fleas have anchoring mouthparts which allow them to attach firmly to the host for long periods.  Burrowing fleas tunnel through the skin.

Ectoparasites have also adapted their body shape to minimise the damage from hair and feathers which form an abrasive and intrusive environment. For this reason reduction in the size of antennae is common in permanent ectoparasites.