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#56: Fleas


Litinsects #56: Fleas

If you have pets, you may have already recognized this... It’s a flea! Fleas are wingless external parasites that feed on the blood of mammals and birds. They make up the order SIPHONAPTERA, from the Greek „siphon“ meaning “tube/pipe” and „aptera“ meaning “wingless” (I love it, another perfectly fitting name!)

-Adaptations to the parasitic lifestyle include piercing/sucking mouthparts, claws to hold on to their hosts, and LATERALLY FLATTENED bodies (narrow when viewed from above), which makes it easier to move through host fur or feathers. They are also covered in tiny backwards-pointing hairs, which help anchor them to a host

-Though they have no wings, fleas are able to jump a distance of 50-200x their body length, which is how they get onto a host. The jump is faster than any muscle is capable of contracting. Instead, energy is stored in an elastic pad of protein called RESILIN. The pad is compressed and held in place by a tendon and can be released to rapidly extend the hindlegs, similar to a bowstring

-Fleas are HOLOMETABOLOUS, meaning they go through complete metamorphosis from egg to larva to pupa to adult. This life cycle is pretty flexible so fleas can actually wait until conditions are ideal for them to move onto the next life stage

-Fleas are usually able to feed on multiple animal species but some are host-specific breeders

-The oriental rat flea is a VECTOR (spreading a disease-causing agent) of the bacterium responsible for plague, which in the 1300s caused one of the deadliest pandemics in human history. While you may be quick to demonize fleas, they actually die from this process as well. First, the digestive tract of an infected flea become physically blocked by bacteria leading it to desperately bite more and more hosts to try to feed (thereby spreading the bacteria) but in the end the flea starves to death

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