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Tsetse fly

life science Maturity 5-7 Next article →

The tsetse fly belongs to the genus Glossina. These insects are large biting flies found in tropical Africa and the Arabian Peninsula.

Tsetse-BKF-2
Tsetse-BKF-2

They are classified as obligate parasites. This means they must feed on the blood of vertebrate animals to survive. Tsetse flies are scientifically important because they act as biological vectors. A vector is an organism that carries and transmits a disease.

Trypanosoma sp. PHIL 613 lores
Trypanosoma sp. PHIL 613 lores

Specifically, they transmit trypanosomes. These tiny organisms cause human and animal trypanosomiasis. This disease has major impacts on public health and the economy in sub-Saharan Africa.

Adult tsetse flies have a very specific body plan, or bauplan.

Dipteran-fly-structure
Dipteran-fly-structure

You can identify them by four main physical features. First, they have a long, thin proboscis. This mouthpart is attached to the bottom of the head by a distinct bulb and points directly forward.

tsetse head-proboscis
tsetse head-proboscis

Second, they have unique wings. When resting, they fold their wings completely over their abdomens. One wing rests directly on top of the other.

tsetse foldedWings
tsetse foldedWings

Third, the wing has a discal medial cell with a hatchet shape. This looks like a meat cleaver or a hatchet.

tsetse hatchetCell
tsetse hatchetCell

Finally, their antennae feature an arista with branched hairs.

tsetse aristaHairs labeled
tsetse aristaHairs labeled

The anatomy of the tsetse fly is built for heavy feeding. Like all insects, the body has a head, a thorax, and an abdomen. The large thorax holds three pairs of legs and two wings. The abdomen is wide and short. It can change size dramatically during a meal.

Dipteran-fly-structure
Dipteran-fly-structure

The tsetse has a large crop, which is a part of its digestive system. This allows the fly to consume a blood meal equal to its own body weight. These flies are physically tough. They are much harder to crush than common houseflies.

Tsetse flies have an unusual life cycle called adenotrophic viviparity.

Gándulas de la leche de Glossina
Gándulas de la leche de Glossina

Most insects lay many eggs, but a female tsetse fertilizes only one egg at a time. She keeps the egg inside her uterus. The offspring develops internally through three larval stages. During this time, the mother feeds the larva a milky substance from a modified gland. This process relies on the high quality of the mother's blood meals. After the third larval stage, the larva leaves the mother. It crawls into the ground and forms a hard puparium. Inside this shell, the insect undergoes metamorphosis. It emerges as a full adult after about 35 days.

There are 23 known extant species of tsetse flies. Scientists often group them into three categories based on where they live and how they behave. These include savannah flies, forest flies, and riverine or lacustrine flies.

The morsitans group contains savannah flies. The fusca group contains forest flies. The palpalis group includes riverine flies.

Each group has different hosts. For example, some species feed heavily on warthogs or bushbuck. Others may feed on birds or even crocodiles.

History shows that tsetse flies have existed for a very long time. Fossilized specimens have been recovered from Paleogene rocks. These fossils were found in both Germany and the United States.

glossina palpalis morsitans
glossina palpalis morsitans

In more recent history, the term "tsetse" became common in English during World War II. This happened because of a British de Havilland aircraft called the Tsetse Mosquito. In 2014, scientists achieved a major milestone by sequencing the genome of Glossina morsitans. This helps researchers understand their genetics and how they interact with their environment.

Tsetse flies are also studied for their relationship with other organisms. They have at least three bacterial symbionts. The primary symbiont is called Wigglesworthia. It lives within special cells called bacteriocytes. They also host Sodalis and Wolbachia. These bacteria are part of the fly's complex biological system. Understanding these connections helps scientists manage the diseases the flies carry.

Tsetse-BKF-3
Tsetse-BKF-3
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🖼️ Images & Media (16)
File:tsetse head-proboscis.jpeg
tsetse head-proboscis.jpeg
File:tsetse foldedWings.jpeg
tsetse foldedWings.jpeg
File:tsetse hatchetCell.jpeg
tsetse hatchetCell.jpeg
File:tsetse aristaHairs labeled.jpeg
tsetse aristaHairs labeled.jpeg
File:Gándulas de la leche de Glossina .gif
Gándulas de la leche de Glossina .gif
File:Dipteran-fly-structure.jpg
Dipteran-fly-structure.jpg
File:glossina palpalis morsitans.jpg
glossina palpalis morsitans.jpg
File:Geographic distribution of the morsitans group, subgenus Glossina s.s., as reported in scientific papers – Publication period 1990–2020.png
Geographic distribution of the morsitans...
File:Geographic distribution of the fusca group, subgenus Austenina, as reported in scientific papers – Publication period 1990–2020.png
Geographic distribution of the fusca...
File:Geographic distribution of palpalis group, subgenus Nemorhina, as reported in scientific papers – Publication period 1990–2020.png
Geographic distribution of palpalis...
File:Geographic_distribution_of_tsetse_flies,_genus_Glossina,_in_Africa_as_reported_in_scientific_papers_%E2%80%93_Publication_period1990%E2%80%932020.png
Geographic_distribution_of_tsetse_flies,_g...
File:Trypanosoma sp. PHIL 613 lores.jpg
Trypanosoma sp. PHIL 613 lores.jpg

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