leas are tiny insects from that shape the order of Siphonaptera. The fleas survive on sucking the blood of both mammals and animals. Adults are up to 3mm long and usually brown. Their bodies levelled from sideways enable them to pass through their host’s fur and feathers; strong claws avert them from being dislodged. They don’t have wings and have mouthparts adapted for piercing the skin and sucking blood. Right now over 2,500 species of fleas have been discovered globally. Fleas emerged as ectoparasites of mammals before moving to the other group of birds.
The larvae are like worms and do not have any chewing mouthparts. They feed on organic dreck. The fleas specialise in its host animals and other species. Some species of fleas do not breed at all while the others are less selective. Some families from fleas focus just on one group of host species. For example, the Malaco Psyllidae are only found on Armadillos, the ischnopsyllidae are found on bats and the Chimaeropsydillae on elephant shrews. They are wingless insects 1.5 to 3 mm long, that is agile, their skin tone varies from the reddish-brown of the cat flea. With the assistance of proboscis, or a stylet accommodated to catering by piercing the skin and feeding on their host’s blood through their epipharynx. Fleas legs end in strong claws that are designed to hold on to a host.
Unlike other insects, Fleas do not have compound eyes but instead only have simple eyespots with a simple biconvex lens. Some species even lack eyes altogether. Their bodies are laterally compact, allowing easy activity through the hair, feathers or clothing on the host’s body. The flea’s body is covered with hard plates known as sclerites. These sclerites are covered with infinite hair and short spines directed backwards, which also assists in the movement on the host’s body. The tough body is able to take in a great pressure, which is likely an adaptation to debar them from scratching.
Fleas are holometabolous insects. They cross four metamorphic stages of egg, larva, pupa and Imago (adult). In few species, neither male nor female mature fully before feeding blood as the first time consumption of blood onsets the maturation of the ovaries in females and the dissolution of the testicular plugin males. Copulation soon occurs after that. The flea population constitutes approximately 50% eggs, 35% larvae, 10% pupae and 5% adults.
Champion flea’s 12-inch leap is equal to 200 times the length of its own body. Their long jump is 13 inches and high jump is 13 inches. The high jump is 7 3/4 inches performed at will according to Guinness book of world records. Their high jump is 130 times its own height. 1 flea can jump steadily for three straight days, 600 times an hour. Their lift off-peak acceleration which is 30 times more than what was experienced by astronauts during the launch of the Saturn moon rocket. It was observed that the fleas stay put in the dark and jump in the light. When seen under an electronic microscope at flea’s leg, scientists saw that the shin and toe had gripping claws but the knee was completely smooth. Fleas push it down through the shin on to the toe. Except for the Hedgehog other flea’s too do use the same technique.
Fleas have long legs as compared to their body, the hind pair is well adapted for jumping. The flea’s jump is hefty. It exceeds the general capabilities of muscles and instead of relying on direct muscle power, fleas store the energy using a stretchy substance called ‘resilin’ before releasing it rapidly. Before the muscles deflate and disfigure the resilin pad, tardily keeping the energy in reserve. This energy can then be released very quickly to power leg extension for propulsion. To prevent the premature release of energy of the leg. Therefore the flea’s use ‘catch mechanism’. In the former stages of the jump, the tendon of the primary muscle passes slightly by the coxa trochanter joint. It generates a torque which holds the joint closed with the leg close to the body. To trigger jumping, another muscle pulls the tender forward until it passes the joint axis, generating the opposite torque to extend the leg and power of the jump by the release of stored energy.