Information about Fleas

fleas siphonaptera information about

Fleas are insects from the order Siphonaptera. They are known as external parasites of warm-blooded animals, living off the blood of mammals and birds. They are flattened sideways to enable them to move through their host’s fur or feathers, and have strong claws to prevent themselves from being dislodged. They are wingless insects, with mouthparts adapted for piercing skin and sucking blood and hind legs adapted for jumping.
There are over 2,500 species of fleas worldwide, many of which are little studied. Around 94% of species are associated with mammalian hosts, and only about 3% can be considered to be specific parasites of birds, although they are believed to have originated from mammalian fleas. The most common categories of fleas are: the cat fleas, the bird fleas, and the dog fleas. Exclusively human fleas are extremely rare, though humans can become infested by cat or dog fleas.

fleas siphonaptera information about

Description and distribution of fleas

Adult fleas are small insects, barely measuring between 1,5 – 3,3 mm. They have flattened bodies, which allow them to move easily through the the hairs/feathers, or under the clothing of the hosts, and which can withstand great pressure: an adaptation meant to allow survival against scratching by the host. They have mouthparts that are designed to pierce skin and draw blood, but they do not have the compound eyes generally characteristic to insects; instead, they have simple eyespots with a single biconvex lens, or, in the case of some species, they do not have eyes at all.
Fleas have long legs that are designed to jump and that end in strong claws meant to grasp the host. A flea is actually able to jump vertically up to 18 cm and horizontally up to 33 cm, meaning it is able to jump up to 50 times its own body length, a feat that is second only to froghoppers. To help in comprehending this: if humans could jump as much as fleas, a 1,8 m person could jump 90 m long and 49 m high. Research suggests that fleas are capable of doing this not by means of muscle power, but by means of releasing, all at once, a protein names resilin. They do not have wings, but they are nonetheless very agile. Coloring is generally reddish-brown, but you may see fleas that are light yellow, yellowish black, brown black or jet-black, depending on the species.
Each species of fleas is more or less a specialist in its host, never feeding or breeding on other hosts. Ceratophyllus gallinae, for example, affects poultry and wild birds. Furthermore, some families of fleas are exclusive to a single group of hosts. For example, the Malacopsyllidae family can only be found on species of armadillos, the Ischnopsyllidae only on species of bats, the Chimaeropsyllidae only on elephant shrews. However, some species of fleas will readily infest different hosts if the opportunity arises. Interestingly, it has been found that avian fleas that exploit more than one host actually actively choose species with low immune systems.

A great number of endemic species and genera are distributed in East-Asian, Central-Asian, West-American, Patagonian, Papuan (New Guinean), and East-African zoogeographical sub-regions. It is possible that forest foothills with temperate and subtropical climate present the most favorable conditions for the fleas.
If you are dealing with a flea infestation indoors, it is important to note that not only will fleas infest your pets, but, if conditions are favorable enough to cause the population to grow exponentially in a short period of time, they can easily branch out to living on you, your carpets, your bedding, and can even come to infest your yard. It may also be important to note that it is not necessary to have a pet to contract fleas; humans often become infested by simply being in an environment infested by fleas, since it is estimated that around 95% of eggs, larvae, and pupae live in the environment, as opposed to on an actual host.

Breeding and dietary information of fleas

Fleas go through 4 stages of development: egg, larva, pupa, and adult. Some species of fleas breed all throughout the year, whereas others will synchronize with external factors, such as the hosts’ life cycles or environmental and climatic conditions. At any given time, a flea population consists of roughly 50% eggs, 35% larvae, 10% pupae, and only 5% adults.
Eggs are small, white, and oval-shaped. Depending on the species, they will be deposited on the host itself (in which case they can easily fall off) or on the substrate of the host. Hatching time also varies according to the species, ranging from a mere 2 days to 2 weeks. The total number of eggs in a single batch depends on the species, ranging from only 2 to several dozen. The total number of eggs laid by a single female in its lifetime can range from around 100 to several thousand.
Larvae are small and pale, with bristles covering worm-like bodies. They do not have eyes, and their mouthparts are adapted to chewing. As soon as they have emerged from eggs, larvae will start to feed on any available organic material, such as feces, dead insects, and vegetable matter.
The larvae that have had access to a sufficient amount of food will pupate after 3 molts, weaving silken cocoons. Within these cocoons, they will molt one final time and undergo metamorphosis into adulthood. As is the case with the rest of their development, the exact time period depends on the species and the environmental conditions the pupae are exposed to. Transition to adult form can therefore happen in only 4 days or in many more, as the pupae are also known to have the capacity to delay emergence until a suitable opportunity presents itself. Signs of such an opportunity, which can also be called triggers, include: vibrations, heat, or increased levels of carbon-dioxide, all of which indicate the presence of a host. Completely developed adults can live up to several months without food, so long as they have not emerged from the cocoon.
Once the adult emerges, its primary goal is to find blood. This is because, in most species, both males and females need to feed on blood before becoming capable of reproduction, the first blood meal triggering the dissolution of the testicular plug in males and the maturation of the ovaries in females. After their first meal, copulation soon follows.
An adult flea’s general lifespan is of 2 months. In an ideal environment, ideal temperature of 21 to 30 degrees Celsius, and around 70% humidity, in addition to an appropriate food supply, the adult fleas have been known to live up to a year and a half. However, without a host to provide a blood meal, it can be as short as a couple of days.

As mentioned above, fleas are external parasites that feed on the blood they extract from their hosts. This includes a variety of warm-blooded animals, such as birds, cats, dogs, ferrets, mice, rats, squirrels, as well as humans. Larvae feed on a variety of organic matter, the most important of which are the feces of mature fleas, which contain dried blood. In general, host specificity decreases as the size of the host species decreases. Another factor is the opportunities available to the flea to change host species; this is smaller in colonially nesting birds, where the flea may never encounter another species, than it is in solitary nesting birds. A large, long-lived host provides a stable environment that favors host-specific parasites.

Fleas as pests

Fleas are also known to be the agents responsible for carrying and transferring the bubonic plague from rats to people, which was ultimately responsible for the death of nearly half of the population of Europe during the Middle Ages. They are obligatory blood feeders parasitizing warm-blooded vertebrates.
Fleas are a nuisance to all species they exploit, mainly because they cause an itching sensation that just worsens as the host tries to remove them by scratching, biting, or pecking. Sometimes, the skin around each bite may also become sore or painful, or may develop a rash. However, fleas are much more dangerous than that. While it is true that, generally, a flea’s bite will cause a small, swollen spot to form (which has a puncture hole in the middle, resembling a mosquito bite), in time, this ‘symptom’ worsens, as most species develop an eczematous skin disease, called flea allergy dermatitis. The bites will then form in clusters/lines and will remain itchy and inflamed over several weeks. Frequent scratching, biting, or pecking will lead to loss of hair or feathers. In extreme cases, a flea infestation can lead to anemia.
Furthermore, fleas are also carriers of many other viral and bacterial diseases, among which are murine (endemic) typhus, cat-flea typhus, myxomatosis, or tungiasis. The cat flea, which breeds on both cats and dogs, carries Yersinia pestis, the bacterium that causes bubonic plague.
Contracting most of these diseases from fleas is generally particularly difficult when it comes to humans, but that is unfortunately not the case with pets, which is one more reason why it is so important to take them to the vet and get them treatment as soon as possible.

Fleas can cause problems such as:

  • anemia in young, older or ill pets;
  • transmission of tapeworms to pets;
  • transmission of plagues to cats;
  • rashes to those (people included) who are allergic.

Fleas have a significant economic impact, as in America alone, approximately $2.8 billion is spent annually on flea-related veterinary bills and another $1.6 billion annually for flea treatment with pet groomers. Four billion dollars is spent annually for prescription flea treatment and $348 million for flea pest control. The best prevention method is by keeping a clean home, especially where a pet is present. Washing the pet’s bedding and vacuuming frequently are good practices in controlling the flea population in your house. Whether you want to use natural or chemical measures against fleas, you can check a more detailed description of how to prevent a flea infestation in your house, and also how to get rid of fleas infestation, in our related articles.

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