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Cediopsylla simplexblokha

By Eric Knapp

Geographic Range

Cediopsylla simplex requires rabbits for various aspects of its life. Therefore, it is distributed in the same manner as its host. The widely known cottontail rabbit (Sylvilagus floridanus) and its relatives are preferred hosts (Rothschild and Ford 1972). These rabbits are most heavily concentrated in the eastern United States. (Rothschild and Ford, 1972; Strohlein and Christensen, 1983)

Habitat

Cediopsylla simplex lives on rabbits. Therefore, it can be concluded that these fleas are found in habitats that are suitable for rabbit populations. These fleas can live on rabbits or in the rabbits' nests, though they require host contact for food and reproduction. Specifically, Cediopsylla simplex prefers to inhabit the ears of rabbits, possibly because of favorable temperatures at the ears (Rothschild 1965). The larvae inhabit newborn rabbits and the nest, where fecal deposits serve as a food source. (Rothschild and Ford, 1972; Rothschild, 1965)

Physical Description

Fleas are small, just visible to the naked eye. To see the features of the flea body, low power light microscopy is suitable. However, for fine details, electron microscopy is necessary (Amrine and Lewis 1978).

All fleas lack wings. There are six legs, and the back pair is specialized to facilitate an incredible jumping ability. The mouthparts are specialized for a piercing-sucking feeding behavior. The mouthparts consist of paired laciniae which surround the epipharynx, forming the food channel. Labial palps protect the mouthparts, while maxillary palps aid in sensory aspects of feeding (Amrine and Lewis 1978). Cediopsylla simplex also has a genal ctenidium. This is a comb-like structure on the side of the head that prevents the insect from being moved through the hair of its host. The vertical orientation of the genal ctenidium helps distinguish this species from other species of fleas, including cat fleas, Ctenocephalides felis, and dog fleas, Ctenocephalides canis.

Flea larvae resemble tiny white maggots. They are eyeless and legless, covered in short bristles, and possess mandibles for chewing. Flea pupae spin silken coccoons that are often studded with debris picked up from the nearby area. (Amrine and Lewis, 1978; Roberts and Janovy, 1996)

Development

The flea life cycle consists of three distinct stages, characteristic of complete metamorphosis: larva, pupa, and adult. Larvae develop within the eggs for anywhere from two days to over a month, depending on temperature and humidity. There are three larval stages, or instars; overall, the larval period lasts anywhere from 9 to 200 days, also depending on temperature and humidity. The pupal stage can last up to a year in unfavorable conditions. Maturation of adult Cediopsylla simplex is closely tied to hormone fluctuations of host rabbits; cortisol and corticosterone released by pregnant female rabbits stimulate adult fleas to develop sexually. (Roberts and Janovy, 1996)

Reproduction

Mating takes place on newborn rabbits. Not much else is known about the mating systems of this species. (Roberts and Janovy, 1996)

The reproductive behavior of Cediopsylla simplex has earned it much attention from the research community. These fleas have evolved a reproductive schedule that precisely coincides with that of its rabbit host (Rothschild and Ford 1972). This coordination is achieved through hormonal control. Pregnant rabbits present an increase in hormones such as cortisol and corticosterone to the blood stream, from which the fleas feed (Roberts and Janovy 1996). The fleas have evolved the ability to detect these hormones, and the fleas only reach sexual maturity when they are detected. Therefore during the rabbit pregnancy the fleas reach sexual maturity, and by the time the baby rabbits are born the female fleas have ripe eggs (Rothschild 1965). When newborn rabbits come in close contact with the head of their mother, the fleas are able to relocate from the mother onto the young rabbits. While on the young rabbits, the fleas feed heavily and they detect the hormone somatropin from the baby rabbits, which stimulates the fleas to mate and lay their eggs (Roberts and Janovy 1996). Like all flea eggs, the eggs of C. simplex are not sticky and thus fall into the nest of the host. While on the young rabbits the adult fleas also defecate at a highly increased rate, creating a food source for the larvae that will soon emerge from the eggs (Rothschild 1965). The fleas then return to the adult rabbit. (Roberts and Janovy, 1996; Rothschild and Ford, 1972)

  • Breeding interval
    The breeding interval is tied to the breeding interval of the host; for Sylvilagus floridanus, this is every month or so during the spring and summer, depending on latitude.
  • Breeding season
    These fleas breed when their hosts do, during the spring and summer.
  • Range gestation period
    2 to 30 days

Female fleas provide nutrients to their eggs before laying them; after that, there is no further involvement on the part of the parents. (Roberts and Janovy, 1996)

  • Parental Investment
  • pre-fertilization
    • provisioning
    • protecting
      • female

Lifespan/Longevity

Although no specific information is available on the lifespan of C. simplex, other flea species have been known to live two to three years given a steady food supply and favorable climate. (Roberts and Janovy, 1996)

Behavior

Cediopsylla simplex spends more time in association with its host than many fleas do. It attaches itself to the ears of rabbits and hangs on for long intervals, leaving only to breed. Many flea species must leave their hosts when not feeding because mammalian body temperatures are too high; perhaps C. simplex can hang on longer because the temperature of the rabbit's ears is more tolerable than the rabbit's core body temperature.

Like all fleas, Cediopsylla simplex is specialized for jumping. It has a highly elastic protein called resilin at the joints of its legs that allows it to launch itself high into the air while expending very little energy. This adaptation allows fleas to quickly hitch rides on passing hosts.

Fleas are not known to associate with one another, except during breeding. (Roberts and Janovy, 1996; Rothschild, 1965)

Communication and Perception

Fleas have a sensory organ called a pygidium near the rear of their bodies that allows them to detect vibrations and air currents. No information is available on how fleas communicate with one another. (Roberts and Janovy, 1996)

Food Habits

Cediopsylla simplex feeds on the blood of its host. It has piercing-sucking mouthparts consisting of a fascicle made up of three stylets. The lacinia cut the skin while the epipharynx draws blood out of a host blood vessel (Roberts and Janovy 1996). These fleas prefer to feed on the ears of their rabbit host, and once there they tend to remain with their mouthparts embedded for long periods of time (Rothschild 1965). Electron microscopy reveals three rows of teeth on the lacinia, demonstrating that they are in fact making incisions into the skin (Amrine and Lewis 1978). The larvae of Cediopsylla simplex feed on the feces of their parents, which is abundant in rabbits' nests, and on the newborn rabbits.

Though Cediopsylla simplex pierces the skin of its host and feeds on its blood, there seems to be minimal mechanical damage to the host. Little or no hemorrhage is observed when a feeding flea removes its stylets from the host (Roberts and Janovy 1996). (Amrine and Lewis, 1978; Roberts and Janovy, 1996; Rothschild, 1965)

  • Animal Foods
  • blood

Ecosystem Roles

Cediopsylla simplex is commonly known as the rabbit flea. It is a nidicolous ectoparasite of rabbits (Roberts and Janovy 1996). Various literature sources cite the cottontail rabbit (Sylvilagus floridanus) as a host (Rothschild and Ford 1972). These fleas require the rabbit hosts for many aspects of their survival. They feed on the blood of the rabbits, they live on them or in their nests, and most interestingly, they have adapted a sychronization of their reproductive cycle to that of their hosts. (Roberts and Janovy, 1996; Rothschild and Ford, 1972)

Species Used as Host

Economic Importance for Humans: Positive

Cediopsylla simplex is a vector for the virus that causes myxomatosis. The virus is fatal to rabbits, and therefore can be theoretically used to control wild rabbit populations. (Roberts and Janovy, 1996)

  • Positive Impacts
  • controls pest population

Economic Importance for Humans: Negative

Rabbit fleas do not frequently bite people. However, because they carry myxomatosis, they are potentially damaging to the domestic rabbit industry. (Roberts and Janovy, 1996)

Contributors

Allison Poor (editor), University of Michigan-Ann Arbor.

Eric Knapp (author), University of Michigan-Ann Arbor, Solomon David (editor), University of Michigan-Ann Arbor.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

agricultural

living in landscapes dominated by human agriculture.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

causes or carries domestic animal disease

either directly causes, or indirectly transmits, a disease to a domestic animal

detritus

particles of organic material from dead and decomposing organisms. Detritus is the result of the activity of decomposers (organisms that decompose organic material).

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

fertilization

union of egg and spermatozoan

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

internal fertilization

fertilization takes place within the female's body

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

metamorphosis

A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

parasite

an organism that obtains nutrients from other organisms in a harmful way that doesn't cause immediate death

saltatorial

specialized for leaping or bounding locomotion; jumps or hops.

sanguivore

an animal that mainly eats blood

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

suburban

living in residential areas on the outskirts of large cities or towns.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

vibrations

movements of a hard surface that are produced by animals as signals to others

References

Amrine, J., R. Lewis. 1978. The Topography of the Exoskeleton of Cediopsylla simplex (Baker 1895) (Siphonaptera: Pulicidae). Journal of Parasitology, 64(2): 343-58.

Roberts, L., J. Janovy. 1996. Foundations of Parasitology 6th edition. United States: McGraw-Hill.

Rothschild, M., B. Ford. 1972. Breeding Cycle of the Flea Cediopsylla simplex is Controlled by Breeding Cycle of Host. Science, 178(61): 625-6.

Rothschild, M. 1965. FLEAS. Scientific American, 213(44): 44-53.

Strohlein, D., B. Christensen. 1983. Metazoan Parasites of the Eastern Cottontail Rabbit in Western Kentucky. Journal of Wildlife Diseases, 19(1): 20-3.

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