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Rhodnius prolixus

By Ramy Kurdi

Geographic Range

Rhodnius prolixus are found in northern South America and Central America. (Roberts and Janovy, 2000)

Habitat

Rhodnius prolixus hide by day in cracks and crevices, principally in domestic areas. (Roberts and Janovy, 2000; Tobie, 1965)

Physical Description

Rhodnius prolixus are large bugs, up to 34 mm in length. They have concave wings on top of the abdomen and are reddish-brown in color. Rhodnius prolixus have a long narrow head with slender four-segmented antennae, compound eyes, and two ocelli present behind the eyes. The clypeus at the front of the head is broad at the top. Rhodnius prolixus have sucking mouthparts which fold back beneath the head and thorax when at rest. The mouthparts consist of long stylets that include a short labrum with a long tubular labium that contains the mandibles and the maxillae. The maxillae enclose a food canal for sucking fluid, and a salivary canal that injects saliva while biting a host.

Juvenile stages of R. prolixus are called nymphs and are hemimetabolous, developing to resemble the adult more with each incomplete metamorphosis. Nymphs have compound eyes, well-developed appendages, wing buds, and develop external genitalia. There is a slight sexual dimorphism with the males being smaller than the females. (Lange, et al., 1989; Roberts and Janovy, 2000)

  • Sexual Dimorphism
  • female larger
  • Range length
    34 (high) mm
    1.34 (high) in

Development

Nymph development occurs across five instars. The first, second, and third instars are non-feeding. During the fourth instar, nymphs begin to feed on blood from host tissues and assume adult behavior. (Ampleford and Davey, 1989; Roberts and Janovy, 2000)

Reproduction

Males detect the presense of a nearby female by her fecal deposits. Mating often involves a complex behavioral pattern with many steps, including male vigilance, female advancement, gyration, copulation, and separation. (Ampleford and Davey, 1989; Roberts and Janovy, 2000)

Rhodnius prolixus lay eggs in a circadian rhythm that is influenced by light and dark cycles. (Ampleford and Davey, 1989; Roberts and Janovy, 2000)

Behavior

Rhodnius prolixus are nidicolous, nocturnal insects that frequent many different sites and feed on a diversity of vertebrate animals. Rhodnius prolixus feed by night on sleeping vertebrate subjects that often fail to detect their painless bites. (Roberts and Janovy, 2000)

Food Habits

Rhodnius prolixus are ectoparasitic solenophages that feed primarily on the blood of mammals and birds. Rhodnius prolixus have sucking mouthparts which fold back beneath the head and thorax when at rest. The mouthparts consist of long stylets that include a short labrum with a long tubular labium that contains the mandibles and the maxillae. The maxillae enclose a food canal for sucking fluid, and a salivary canal that injects saliva to help digest host tissue.

The saliva contains some anticoagulants, and the painless bites of R. prolixus are usually around the eyes and mouth of the host, where they can suck blood for several minutes. Endosymbiotic bacteria help to digest the blood ingested by R. prolixus. The bacteria are contained in epithelial cells of the triatomine gut and are found among many of its tissues throughout its growth and maturation.

Dogs, cats, and rats are important Rhodnius prolixus hosts in urban environments. Some other less common hosts include opossum, armadillos, bats, squirrels, wild rats and mice, guinea pigs and sloths. The R. prolixus population size depends on the number of hiding places and available hosts, especially in domestic areas. (Lange, et al., 1989; Roberts and Janovy, 2000; Tobie, 1965)

  • Animal Foods
  • blood

Economic Importance for Humans: Positive

There are no known economic benefits derived from Rhodnius prolixus.

Economic Importance for Humans: Negative

Rhodnius prolixus are vectors for human disease. Rhodnius prolixus are the principle vector for Trypanosoma cruzi, the agent of Chagas' disease, in northern South America. Rhodnius prolixus is also a vector for Trypanosoma (Herpetosoma) rangeli, which causes a common disease in dogs, cats and humans in Central America. The method of transmission is through feeding of, and fecal contamination by R. prolixus as it excretes its waste on the host while feeding. Millions of dollars are spent annually to eradicate Chagas' disease by improving unsanitary living conditions and screening all blood donors. (Garcia and Azambuja, 1991; Lange, et al., 1989; Tobie, 1965)

Conservation Status

This species requires no special status and is not endangered.

Contributors

Sara Diamond (editor), Animal Diversity Web.

Ramy Kurdi (author), University of Michigan-Ann Arbor, Teresa Friedrich (editor), University of Michigan-Ann Arbor.

Glossary

Neotropical

living in the southern part of the New World. In other words, Central and South America.

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 disease in humans

an animal which directly causes disease in humans. For example, diseases caused by infection of filarial nematodes (elephantiasis and river blindness).

causes or carries domestic animal disease

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

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.

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

internal fertilization

fertilization takes place within the female's body

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.

nocturnal

active during the night

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

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

sanguivore

an animal that mainly eats blood

scrub forest

scrub forests develop in areas that experience dry seasons.

sexual

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

suburban

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

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

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.

urban

living in cities and large towns, landscapes dominated by human structures and activity.

References

Ampleford, E., K. Davey. 1989. Egg laying in the insect Rhodnius prolixus is timed in a circadian fashion.. J. Insect Physiology, 35: 183-188.

Garcia, E., P. Azambuja. 1991. Development and interactions of Trypanosoma cruzi in insect vector.. Parasitology Today, 7: 240-244.

Lange, A., I. Orchard, F. Barrett. 1989. Changes in the hemolymph serotonin levels associated with feeding in the blood-sucking bug, Rhodnius prolixus.. J. Insect Physiology, 35: 393-400.

Roberts, L., J. Janovy. 2000. Foundations of Parasitology 6th edition. New York: McGraw-Hill.

Tobie, E. 1965. Biological factors influencing transmission of Trypanosoma rangeli by Rhodnius Prolixus.. J. Parasitology, 51: 837-841.

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