Some flea species include:
Over 2,000 species have been described worldwide.
[2]
[edit]Morphology and behavior
Fleas are wingless insects (1/16 to 1/8-inch (1.5 to 3.3 mm) long) that are agile, usually dark
colored (for example, the reddish-brown of the cat flea), with tube-like mouth-parts adapted to
feeding on the blood of their hosts. Their legs are long, the hind pair well adapted for jumping:
a flea can jump vertically up to 7 inches (18 cm) and horizontally up to 13 inches (33 cm).
[3]
This is around 1200 to 2200 times their own body length, making the flea one of the best jumpers of
all known animals (relative to body size), second only to the
froghopper. According to an article
in
Science News, "researchers with the University of Cambridge in England have shown that fleas
take off from their tibiae and tarsi—the insect equivalent of feet—and not their trochantera, or knees.
The researchers report their conclusion in the March 1 Journal of Experimental Biology."
[4]
It has been known that fleas do not use muscle power but energy stored in a protein named
resilinbut
the researchers used high-speed video technology and mathematical models to discover where
the spring action actually happens. Their bodies are laterally compressed, permitting easy movement
through the hairs or feathers on the host's body (or in the case of humans, under clothing).
The flea body is hard, polished, and covered with many hairs and short spines directed backward,
[5]
which also assist its movements on the host. The tough body is able to withstand great pressure,
likely an adaptation to survive attempts to eliminate them by mashing or scratching. Even hard
squeezing between the fingers is normally insufficient to kill a flea. It is possible to eliminate them
by pressing individual fleas with adhesive tape or softened beeswax (or "cheese" wax) or by rolling
a flea briskly between the fingers to disable it then crushing it between the fingernails. Fleas also can
be drowned in water and may not survive direct contact with anti-flea
bristles covering its worm-like body, lacks eyes, and has mouthparts adapted to chewing. The larvae
feed on various organic matter, especially the feces of mature fleas. The adult flea's diet consists solely
of fresh blood.
[6] In the pupal phase, the larva is enclosed in a silken, debris-covered cocoon.
[edit]Life cycle and habitat
Fleas are
holometabolous insects, going through the four
life cycle stages of
egg,
larva,
pupa, and
imago
(adult). The flea life cycle begins when the female lays after feeding. Adult fleas must feed on blood before
they can become capable of reproduction.
[5] Although reproduction is normally asexual, for at least one
specie, under stress conditions, female fleas produce male fleas.
[7]. Eggs are laid in batc
hes of up to 20 or so, usually on the host itself, which means that the eggs can easily roll onto the ground.
Because of this, areas where the host rests and sleeps become one of the primary
habitats of eggs and
developing fleas. The eggs take around two days to two weeks to hatch.
[3]
Flea larvae emerge from the eggs to feed on any available organic material such as dead insects, feces,
and vegetable matter. They are blind and avoid sunlight, keeping to dark places like sand, cracks and
crevices, and bedding. Given an adequate supply of food, larvae should
pupate and weave a
silken cocoon
within 1–2 weeks after 3 larval stages. After another week or two, the adult flea is fully developed and ready
to emerge from the cocoon. They may however remain resting during this period until they receive a
signal that a host is near - vibrations (including sound), heat, and
carbon dioxide are all stimuli indicating
the probable presence of a host.
[3] Fleas are known to
overwinter in the larval or pupal stages.
Once the flea reaches adulthood, its primary goal is to find blood and then to reproduce.
[8] Adult fleas only
have about a week to find food once they emerge, but after that they can survive two years to three years
between meals. Flea populations are evenly distributed, with about 50% eggs, 35% larvae, 10% pupae,
and 5% adults.
[3] Their total life cycle can be as short as one year, but may be several years in ideal conditions.
Female fleas can lay 5000 or more eggs over their life, allowing for phenomenal growth rates.
Adult female rabbit fleas,
Spilopsyllus cuniculi, can detect the changing levels of cortisol and corticosterone,
hormones in the rabbit's blood that indicate she is getting close to giving birth. This triggers sexual maturity
in the fleas and they start producing eggs. As soon as the baby rabbits are born, the fleas make their way
down to them and once on board they start feeding, mating, and laying eggs. After 12 days, the adult fleas
make their way back to the mother. They complete this mini-migration every time she gives birth.
[9]
Newly emerged adult fleas live only about one week if a blood meal is not obtained. However, completely
developed adult fleas can live for several months without eating, so long as they do not emerge from their
puparia. Optimum temperatures for the flea's life cycle are 70°F to 85°F (21°C to 30°C) and optimum humidity
is 70%.
[9]
[edit]Classification
Fleas are related to
mecoptera,
[10] winged insects with good eyesight. The flightless
boreid (snow scorpionfly)
with its
rudimentary wings seems to be close to the common ancestor of the 2000 or so known varieties
of flea.
[10] Their evolution continued to produce adaptations for their specialized parasitic niche, such that
they now have no wings and their eyes are covered over. The large number of flea species may be attributed
to the wide variety of host species they feed on, which provides so many specific
ecological niches to adapt to.
In the past, it was most commonly supposed that fleas had evolved from the
flies (
Diptera), based on
similarities of the larvae. (Some authorities use the name
Aphaniptera because it is older,
but
names above family rank need not follow the
ICZN rules of priority, so most
taxonomists use the
more familiar name).
Genetic and morphological evidence indicates that they are descendants of
the
Scorpionfly family
Boreidae, which are also flightless; accordingly it is possible that they will
eventually be reclassified as a suborder within the
Mecoptera. In any case, all these groups seem
to represent a
clade of closely related insect lineages, for which the names Mecopteroidea and
Antliophora have been proposed.
Flea
systematics are not entirely fixed. While, compared to many other insect groups, fleas have
been studied and classified fairly thoroughly, details still remain to be learned about the
evolutionary
relationships among the different flea lineages.
- Infraorder Pulicomorpha
- Superfamily Pulicoidea
- Superfamily Malacopsylloidea
- Family Malacopsyllidae
- Family Rhopalopsyllidae—hosts
- Family Vermipsyllidae—hosts: carnivores
- Superfamily Coptopsylloidea
- Superfamily Ancistropsylloidea
- Infraorder Pygiopsyllomorpha
- Superfamily Pygiopsylloidea
- Family Lycopsyllidae
- Family Pygiopsyllidae
- Family Stivaliidae
- Infraorder Hystrichopsyllomorpha
- Superfamily Hystrichopsylloidea
- Family Hystrichopsyllidae—hosts: rats and mice. Includes Ctenopsyllidae, Amphipsyllidae
- Family Chimaeropsyllidae
- Superfamily Macropsylloidea
- Superfamily Stephanocircidoidea
[edit]Relationship with host
Fleas attack a wide variety of
warm-blooded vertebrates including dogs, cats, humans, chickens, rabbits,
squirrels, rats, ferrets, and mice.
[edit]Direct effects of bites
Fleas are a nuisance to their hosts, causing an
itching sensation which in turn may result in the host
attempting to remove the pest by biting, pecking, scratching, etc. in the vicinity of the parasite. Fleas
are not simply a source of annoyance, however. Some people and animals suffer
allergic reactionsto flea
saliva resulting in
rashes. Flea bites generally result in the formation of a slightly raised, swollen itching
spot with a single puncture point at the center (similar to a
mosquito bite). The bites often appear in
clusters or lines of two bites, and can remain itchy
and inflamed for up to several weeks afterwards. Fleas can also lead to hair loss as a result of frequent
scratching and biting by the animal, and can cause
anemia in extreme cases.
[11]:126
[edit]As a vector
Fleas that specialize as parasites on specific mammals may use other mammals as hosts; therefore
humans are susceptible to the predation of more than one species of flea.
[15]
A misconception concerning the carrying/transmission of the HIV/AIDS by fleas has been debunked by
the Centers for Disease Control and Prevention (CDC 2003), which stated that fleas cannot carry the virus
and spread it to other humans.
[edit]Flea treatments
[edit]For humans
[edit]For pets
Modern flea control is approached using
Integrated Pest Management (IPM) protocols at the host (pet) level.
IPM is achieved by targeting fleas during at least two separate life stages, with at least two separate molecules.
This is typically achieved using an
adulticide to kill adult fleas and an insect development inhibitor (IDI),
like
lufenuron, or insect growth regulator (IGR), like
methoprene, to prevent development of immature stages.
Flea adults, larvae, or eggs can be controlled with
insecticides.
Lufenuron is a veterinary preparation
(known as
Program) that attacks the larval flea's ability to produce
chitin, necessary for the adult's
hard
exoskeleton, but does not kill fleas. Flea medicines need to be used with care because many
of them also affect mammals.
Flea and tick ointment is hazardous to humans; the label of a commercial preparation warns:
“First aid: If on skin or clothing, take off contaminated clothing, rinse skin immediately with plenty
of water for 15 – 20 minutes; call a poison control center or doctor for treatment advice. . . Although
(the product is) applied only between the shoulder blades and at the base of the tail, the dog’s skin
and hair oils carry the product over the entire body . . . Wash thoroughly with soap and water after handling . . .”
[18]
Cedar oil, a non-toxic natural substance, has been proven effective in the eradication of infestations in pets.
Cedar oil is being used to treat sand-flea infestation of
US Military forces in the Persian Gulf.
[19]
Since more than three quarters of a flea's life is spent somewhere other than on the host animal, it is
not adequate to treat only the host; it is important also to treat the host's environment. Thorough vacuuming,
washing linens in hot water, and treating all hosts in the immediate environment (the entire household, for example) are essential and
if possible on a regular basis.
[20]
Contemporary commercial products for the topical treatment of flea infestations on pets contain
pesticides such as
imidacloprid,
permethrin, and (S)-
methoprene. All flea control products are recommended
to be used at least half-yearly because the
lifecycle of flea and tick can last to up to 6 months, and by using
one of the flea and tick control products for so long, the infestation is highly prevented and, in the end, stopped
.
Although all these products are effective in fighting against flea and tick infestations, they have different active ingredients and, because cats cannot metabolize
some of the compounds of the product, care must be taken in their use.
[edit]For the home
Combatting a flea
infestation in the home takes patience because for every flea found on an animal,
there could be many more developing in the home. A spot-on insecticide will kill the fleas on the pet and in
turn the pet itself will be a roving flea trap and mop up newly hatched fleas. The environment should be treated
with a fogger or spray insecticide containing an insect growth regulator, such as pyriproxyfen or methoprene to kill eggs and pupae,
which are quite resistant against insecticides. Frequent vacuuming is also helpful, but the vacuum bag must be disposed of immediately
afterwards.
Flea "dirt" in the fur of a cat is actually excess blood from the host consumed by the adult flea and passed as feces
Diatomaceous earth can also be used as a home flea treatment in lieu of
acetylcholinesterase
inhibitory treatments or insecticides which carry with them a risk of poisoning for both humans and
animals. However, Diatomaceous earth is at least potentially dangerous to pets and people when inhaled,
so care in use is recommended. Application is effective on both the interior and exterior of one's property,
but the efficacy of Diatomaceous earth is diminished when introduced to water.
[21] Because Diatomaceous
earth is commonly available in food grade quality, it is also possible to leave it exposed in areas typically
vulnerable to fleas and other insects.
Dried
pennyroyal has been suggested as a natural flea control,
[22] but is not recommended in homes with
pets due to its high toxicity to mammals.
[23]
Borax is sold as a "Natural Laundry Booster" and can also be used as another home treatment for
flea infestations. Borax contains
sodium boratewhich kills fleas by dehydrating them, but its safety for
pets is untested.
[24]
Using
dehumidifiers with
air conditioning and
vacuuming all may interrupt the flea
life cycle. Humidity is
critical to flea survival. Eggs need relative humidity of at least 70–75% to hatch, and larvae need at
least 50% humidity to survive. In humid areas, about 20% of the eggs survive to adulthood; in
arid areas,
less than 5% complete the cycle.
[25] Fleas thrive at higher temperatures, but need 70° to 90°F (21° to 32°C)
to survive. Lower temperatures slow down or completely interrupt the flea life-cycle. A laboratory study done
at the
University of California showed that vacuuming catches about 96% of adult fleas. A combination of
controlled humidity, temperature, and vacuuming should eliminate fleas from an environment. Altering even
one of these environmental factors may be enough to drastically lower and eliminate an infestation.
[edit]See also
[edit]References
- Notes
- ^ Huang, D., Engel, M.S., Cai, C., Wu, H., Nel, A. (2012).
- "Diverse transitional giant fleas from the Mesozoic era of China". Nature, in press. doi:10.1038/nature10839.
- ^ Fleas: What They Are, What To Do D. L. Richman and P. G. Koehler, University of Florida
- IFAS Extension. Accessed 10 December 2010
- ^ a b c d [1] Crosby, J.T. What is the Life Cycle of the Flea. Accessed 6 August 2012
- ^ http://www.sciencenews.org/view/generic/id/69664/title/Fleas_leap_from_feet%2C_not_knees
- ^ a b Fleas. P.G. Koehler and F. M. Oi. Printed July 1993, revised February 2003. Provided by the University of Florida
- ^ Order Siphonaptera – Fleas – BugGuide.Net Accessed 28 December 2006
- ^ http://www.cals.ncsu.edu/agcomm/magazine/spring05/sex.htm
- ^ http://edis.ifas.ufl.edu/IG087
- ^ a b Piper, Ross (2007), Extraordinary Animals: An Encyclopedia of Curious and Unusual Animals,
- Greenwood Press.
- ^ a b Grimaldi, D. and Engel, M.S. (2005). Evolution of the Insects.
- Cambridge University Press. ISBN 0-521-82149-5.
- ^ a b Mullen, Gary R.; Mullen, Gary; Durden, Lance (2009). Medical and Veterinary Entomology. Academic Press. pp. 637. ISBN 978-0-12-372500-4. Retrieved 2010-04-09.
- ^ a b c Krasnov, Boris R. (2008). Functional and evolutionary ecology of fleas: a model for ecological parasitology.
- Cambridge University Press. pp. 593. ISBN 978-0-521-88277-4. Retrieved 2010-04-09.
- ^ [|Sherman, David M.] (2002). Tending animals in the global village: a guide to international veterinary medicine.
- Wiley-Blackwell. p. 209. ISBN 978-0-683-18051-0. Retrieved 2010-04-09.
- ^ Stein, Ernst (2003). Anorectal and colon diseases: textbook and color atlas of proctology. Springer.
- p. 478. ISBN 978-3-540-43039-1. Retrieved 2010-04-09.
- ^ Barnes, Ethne (2007). Diseases and Human Evolution. UNM Press. p. 253. ISBN 978-0-8263-3066-6.
- Retrieved 2010-04-09.
- ^ Scott, Susan; Thomas, Craig (2000).
- Pests of Paradise: First Aid and Medical Treatment of Injuries from Hawaii's Animals. University of
- Hawaii Press. p. 58. ISBN 978-0-8248-2252-1. Retrieved 2010-04-08.
- ^ Jacoby, David B.; Youngson, R.M. (2004). Encyclopedia of Family Health. Marshall Cavendish. p. 647.
- ISBN 978-0-7614-7486-9. Retrieved 2010-04-08.
- ^ Label of Bio Spot spot on flea and tick control for dogs. 2007, 2010. Phoenix, AZ: Farnam Companies, Inc.
- ^ "Lights Out For Bed Bugs as "BEST YET" Cedar Oil Solution Solves International Bed Bug Dilemma".
- http://www.prweb.com/.+2008-11-25. Retrieved 2010-04-08.
- ^ ntp.niehs.nih.gov/ntp/htdocs/Chem.../cedarwood_oil.pdf
- ^ How to Get Rid of Fleas: Redux
- ^ Natural Flea Control, 1987, Mother Earth News, Retrieved 2007-12-18
- ^ Warnings About Essential Oils
- ^ Fleas
- ^ Fleas Management Guidelines. Univ. of California Division of Agriculture and Natural Resources,
- Nov. 2000.
[edit]External links
