Glossina morsitans

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Geographic Range

Glossina morsitans is found in Africa and the Arabian Peninsula beneath the Tropic of Cancer. (Lehane M, 1991)

Habitat

Glossina morsitans can be found in savannah during the wet season, but in the dry season prefers shaded wooded areas. They always remain in the lowlands however, due to their inactivity at temperatures below 18°C. (Askew R, 1971; Lehane M, 1991; Roberts S and Javony L, 2000)

Physical Description

Glossina morsitans is 7.5 to 14 millimeters long and is brownish gray in color. its wings cross like scissors and it has recognizable branched arista on the antennae. Adults have highly specialized mouthparts used to bite and lap up blood. (Askew R, 1971; Roberts S and Javony L, 2000)

  • Range length
    7.5 to 14 mm
    0.30 to 0.55 in

Development

Copulation lasts an hour, and after fertilization the embryo is kept within the females uterus. While still in utero, the embryo develops into the first juvenile stage and hatches. The larvae pass through the first, second, and third larval instars on the first, midway through the second, and fifth day respectively. "Milk" glands from the mother's reproductive tract provide nourishment during this time. The adult female must have three blood meals in order to sustain a single progeny.

Larval respiration occurs through a pair of posterior spiracles during the first two instars and then is altered into a two-way respiration system as it moves into the third and final larval instar and prepares for birth. Upon full larval development in the third instar, lasting approximately four days, the female deposits the larva, which is nearly as big as the adult into a suitable environment of loose soil. Once here, the larva has about an hour in which to dig underground. Once under the soil the larva turns black and forms a puparium that hardens over the next four days. Pupae remain underground for about a month. Upon emergence, the adult fly is capable of flight after an hour, and begins to form sclerotized cuticle over the nine day teneral period. (Askew R, 1971; Chapman R, 1998; Lehane M, 1991; Malele I, 1999; Roberts S and Javony L, 2000)

Reproduction

The female tse tse fly is capable of mating within one day of eclosing from the puparium. She produces a pheromone in the waxy cuticle on her wings to attract a mate. Copulation lasts an hour, and after fertilization the embryo is kept within the females uterus. (Askew R, 1971; Chapman R, 1998; Lehane M, 1991; Malele I, 1999; Roberts S and Javony L, 2000)

After fertilization the embryo is kept within the females uterus. The embryo develops into the first juvenile stage, hatches, and begins life outside the egg while still in utero. (Askew R, 1971; Chapman R, 1998; Lehane M, 1991; Malele I, 1999; Roberts S and Javony L, 2000)

  • Parental Investment
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female
  • pre-independence
    • provisioning
      • female

Behavior

Glossina morsitans are diurnal, and only active between the temperatures of 18-32°C. Tse tse flies feed primarily on suids and bovids, but blood from animals as diverse as monitor lizards and hippopotami have been found in their guts. There is no sexual dimorphism in the feeding habits of G. morsitans except that the female must eat more to sustain the large larvae during pregnancy. (Lehane M, 1991; Roberts S and Javony L, 2000)

Communication and Perception

Food Habits

Glossina morsitans, commonly called the tse tse fly, is solely a daytime feeder which is attracted to moving objects visually, but also has an acute sense of smell. They respond to CO2 produced by the exhalation of animals. Both sexes feed exclusively on blood and produce anticoagulants to prevent clotting. They prefer pig blood, but also feed on livestock, wild game, and humans. (Lehane M, 1991; Roberts S and Javony L, 2000)

  • Animal Foods
  • blood

Economic Importance for Humans: Negative

Glossina morsitans is the primary vector of Tyrpanosoma brucei, the causative agent of African sleeping sickness in humans. Transmission occurs when a tse tse fly bites an infected animal and contracts the protozoan while feeding off of its blood. The parasite then rapidly moves to the midintestine of the fly and begins to reproduce. From here they move to the fly's salivary glands and remain there to mature. Once in the epimastigote form, they divide and are ready to be transmitted to a mammalian host via saliva injected into the bite. After transmission, trypanosomes cause a local infection called a chancre, and then proceed into the blood stream. From the bloodstream they can infect the brain and spinal fluid where they remain, and cause the degenerative disease. (Smyth J, 1994)

Conservation Status

This animal requires no special status.

Other Comments

The tse tse fly is a host to the causeative agent of African Sleeping Sickness and thus has become an important vector of human disease. Antelopes are the natural hosts for the causative agent, Trypanosoma brucei. The presence of the trypanosome within the gut of the fly increases the level of feeding and thus increases the vector potential of the tse tse when infected. (Lehane M, 1991; Roberts S and Javony L, 2000)

Contributors

Sara Diamond (editor), Animal Diversity Web.

Robert Fraumann (author), University of Michigan-Ann Arbor, Solomon David (editor), University of Michigan-Ann Arbor.

Glossary

Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map

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

chemical

uses smells or other chemicals to communicate

diurnal
  1. active during the day, 2. lasting for one day.
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.

migratory

makes seasonal movements between breeding and wintering grounds

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.

ovoviviparous

reproduction in which eggs develop within the maternal body without additional nourishment from the parent and hatch within the parent or immediately after laying.

sanguivore

an animal that mainly eats blood

sexual

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

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.

visual

uses sight to communicate

References

Askew R, 1971. Parasitic Insects. New York: American Elsevier.

Chapman R, 1998. The Insects Structure and Function. Cambridge: Cambridge University Press.

Lehane M, 1991. Biology of Blood Sucking Insects. London: Harper Collins.

Malele I, 1999. Mating age of Glossina austeni Newstead. Acta Tropica, 72(3): 319-324.

Roberts S, , Javony L. 2000. Foundations of Parasitology: Sixth Edition. New York: McGraw Hill.

Smyth J, 1994. Introduction to Animal Parasitology: Third Edition. Cambridge: Cambridge University Press.

Spath J, 2000. Feeding Patterns of Three Sympatric Tse tse Species in the Preforest Zone of Côte d'Ivoire. Acta Tropica, 75(1): 109-118.